TCS Interview Questions 2026: Real HR, Technical and Managerial Round Questions

TCS NQT — 100 ACTUAL INTERVIEW QUESTIONS WITH ANSWERS

SQL | OOPs | DBMS | OS | Networks | Coding | Behavioural | Managerial | HR

Digital & Prime Level | All Actually Asked

📋 CATEGORY MAP

🔷 SQL — Q1 to Q12

Q1. ⭐ Write a SQL query to find the second highest salary from the Employee table.

Answer:

-- Method 1: Subquery
SELECT MAX(salary) AS SecondHighest
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);

-- Method 2: DENSE_RANK (handles duplicates correctly)
SELECT salary FROM (
  SELECT salary, DENSE_RANK() OVER (ORDER BY salary DESC) AS rnk
  FROM employees
) t WHERE rnk = 2;

-- Method 3: LIMIT OFFSET (MySQL)
SELECT DISTINCT salary FROM employees
ORDER BY salary DESC
LIMIT 1 OFFSET 1;

Q2. ⭐ What is the difference between WHERE and HAVING clause?

Answer:

-- WHERE filters rows before grouping
SELECT dept, AVG(salary) FROM employees
WHERE salary > 20000
GROUP BY dept
HAVING AVG(salary) > 50000;
-- HAVING filters after grouping

Q3. ⭐ What are the different types of JOINs? Explain with example.

Answer:

INNER JOIN — Only matching rows from both tables.

SELECT e.name, d.dept_name
FROM employees e INNER JOIN departments d ON e.dept_id = d.id;

LEFT JOIN — All rows from left table + matching from right (NULL if no match).

SELECT e.name, d.dept_name
FROM employees e LEFT JOIN departments d ON e.dept_id = d.id;

RIGHT JOIN — All rows from right table + matching from left.

FULL OUTER JOIN — All rows from both tables (NULL where no match).

SELF JOIN — Table joined with itself.

SELECT a.name AS employee, b.name AS manager
FROM employees a JOIN employees b ON a.manager_id = b.id;

CROSS JOIN — Cartesian product of both tables.

Q4. ⭐ What is the difference between DELETE, TRUNCATE, and DROP?

Answer:

DELETE FROM employees WHERE id = 5;   -- removes specific row
TRUNCATE TABLE employees;              -- removes all rows, keeps structure
DROP TABLE employees;                  -- removes table completely

Q5. ⭐ What is the difference between DDL, DML, DCL, and TCL?

Answer:

DDL (Data Definition Language) — Defines structure. Commands: CREATE, ALTER, DROP, TRUNCATE, RENAME

DML (Data Manipulation Language) — Manipulates data. Commands: INSERT, UPDATE, DELETE, SELECT

DCL (Data Control Language) — Controls access. Commands: GRANT, REVOKE

TCL (Transaction Control Language) — Manages transactions. Commands: COMMIT, ROLLBACK, SAVEPOINT

Q6. ⭐ Write a query to find all employees whose name starts with ‘A’.

Answer:

SELECT * FROM employees
WHERE name LIKE 'A%';

-- Other LIKE patterns:
-- LIKE '%A'   → ends with A
-- LIKE '%A%'  → contains A anywhere
-- LIKE '_A%'  → second character is A

Q7. ⭐ What is a GROUP BY clause? Write a query to find department-wise employee count.

Answer: GROUP BY groups rows with the same values into summary rows.

SELECT department, COUNT(*) AS employee_count
FROM employees
GROUP BY department
ORDER BY employee_count DESC;

-- With HAVING to filter groups:
SELECT department, COUNT(*) AS cnt
FROM employees
GROUP BY department
HAVING COUNT(*) > 5;

Q8. ⭐ What is a subquery? What are its types?

Answer: A subquery is a query nested inside another query.

Types:

• Single-row subquery — returns one row: WHERE salary = (SELECT MAX(salary) FROM employees)
• Multi-row subquery — returns multiple rows: WHERE dept_id IN (SELECT id FROM departments WHERE location = 'Mumbai')
• Correlated subquery — references outer query: executes once per outer row
• Scalar subquery — returns single value, used in SELECT list

-- Correlated subquery example:
SELECT name FROM employees e
WHERE salary > (SELECT AVG(salary) FROM employees WHERE dept_id = e.dept_id);

Q9. ⭐ What is an INDEX in SQL? What are its advantages and disadvantages?

Answer: An index is a data structure (usually B-Tree) that speeds up data retrieval from a table.

CREATE INDEX idx_salary ON employees(salary);
CREATE UNIQUE INDEX idx_email ON employees(email);

Advantages:

• Faster SELECT and WHERE query performance
• Faster sorting and ordering

Disadvantages:

• Slows down INSERT, UPDATE, DELETE (index must be updated)
• Consumes additional disk space

When NOT to use: Small tables, columns with many NULL values, columns rarely used in WHERE clauses.

Q10. ⭐ What are aggregate functions in SQL? Give examples.

Answer: Aggregate functions perform calculations on a set of values and return a single value.

SELECT dept, COUNT(*) AS headcount, AVG(salary) AS avg_sal,
       MAX(salary) AS max_sal, MIN(salary) AS min_sal
FROM employees
GROUP BY dept;

Q11. ⭐ What is the difference between UNION and UNION ALL?

Answer:

SELECT name FROM employees_india
UNION
SELECT name FROM employees_usa;  -- unique names only

SELECT name FROM employees_india
UNION ALL
SELECT name FROM employees_usa;  -- all names including duplicates

Q12. ⭐ Write a SQL query to find employees who earn more than the average salary.

Answer:

SELECT name, salary
FROM employees
WHERE salary > (SELECT AVG(salary) FROM employees)
ORDER BY salary DESC;

-- With department-wise average:
SELECT e.name, e.salary, e.department
FROM employees e
WHERE e.salary > (
    SELECT AVG(salary) FROM employees
    WHERE department = e.department
)
ORDER BY e.department, e.salary DESC;

🟠 OOPs — Q13 to Q24

Q13. ⭐ What are the four pillars of OOPs? Explain each with a real-life example.

Answer:

Encapsulation — Wrapping data and methods into a single unit (class) and restricting direct access to data. Real-life: A medicine capsule hides its contents. You take it without knowing what’s inside.

class BankAccount {
    private double balance;          // hidden data
    public double getBalance() { return balance; }  // controlled access
    public void deposit(double amt) { if(amt > 0) balance += amt; }
}

Abstraction — Hiding implementation details, showing only what is necessary. Real-life: You drive a car without knowing how the engine works internally.

abstract class Shape {
    abstract double area();  // what — not how
}
class Circle extends Shape {
    double r;
    double area() { return 3.14 * r * r; }
}

Inheritance — A child class acquires properties and behaviours of a parent class. Real-life: A child inherits traits (eye colour, height) from parents.

class Animal { void eat() { System.out.println("eating"); } }
class Dog extends Animal { void bark() { System.out.println("Woof"); } }

Polymorphism — Same method name behaves differently based on context. Real-life: A person acts differently as a parent, employee, and friend.

• Compile-time (Overloading): same method name, different parameters
• Run-time (Overriding): child class redefines parent method

Q14. ⭐ What is the difference between an abstract class and an interface?

Answer:

abstract class Vehicle {
    String brand;                   // instance variable
    abstract void start();          // must override
    void fuel() { System.out.println("needs fuel"); }  // concrete
}
interface Electric { void charge(); }
class Tesla extends Vehicle implements Electric {
    void start() { System.out.println("silent start"); }
    public void charge() { System.out.println("charging"); }
}

Q15. ⭐ What is the difference between method overloading and method overriding?

Answer:

// Overloading — same class
class Calculator {
    int add(int a, int b) { return a + b; }
    double add(double a, double b) { return a + b; }  // different params
}

// Overriding — child class
class Animal { void sound() { System.out.println("..."); } }
class Cat extends Animal {
    @Override
    void sound() { System.out.println("Meow"); }  // same signature
}

Q16. ⭐ What is a constructor? What are its types? Can a constructor be private?

Answer: A constructor is a special method called when an object is created. It has the same name as the class and no return type.

Types:

• Default constructor — No parameters; provided by Java if no constructor defined
• Parameterised constructor — Takes arguments to initialise fields
• Copy constructor — Creates object by copying another object (C++ has it natively)

Can a constructor be private? Yes — used in Singleton Pattern to prevent external instantiation.

class Singleton {
    private static Singleton instance;
    private Singleton() { }               // private constructor
    public static Singleton getInstance() {
        if (instance == null)
            instance = new Singleton();
        return instance;
    }
}

Q17. ⭐ What is the difference between this and super keyword?

Answer:

class Animal {
    String name;
    Animal(String name) { this.name = name; }
    void display() { System.out.println("Animal: " + name); }
}
class Dog extends Animal {
    String breed;
    Dog(String name, String breed) {
        super(name);           // calls Animal constructor
        this.breed = breed;    // refers to Dog's own field
    }
    void display() {
        super.display();       // calls Animal's display()
        System.out.println("Breed: " + breed);
    }
}

Q18. ⭐ What is a virtual function? What is a pure virtual function?

Answer: Virtual function — A function in base class declared with virtual keyword. Enables run-time polymorphism — the correct overridden version is called through a base class pointer/reference.

Pure virtual function — A virtual function with no body (= 0). Makes the class abstract — cannot be instantiated. Any derived class MUST override it.

class Shape {
public:
    virtual void draw() { cout << "drawing shape"; }    // virtual
    virtual double area() = 0;                           // pure virtual
};
class Circle : public Shape {
public:
    void draw() override { cout << "drawing circle"; }
    double area() override { return 3.14 * r * r; }
private:
    double r = 5;
};
// Shape s;    // ERROR — cannot instantiate abstract class
Circle c;      // OK — all pure virtual functions overridden

Q19. ⭐ What is a destructor? When is it called?

Answer: A destructor is a special method that is automatically called when an object goes out of scope or is explicitly deleted. It cleans up resources (memory, file handles, connections) allocated by the object.

class FileHandler {
    FILE* fp;
public:
    FileHandler(const char* name) { fp = fopen(name, "r"); }
    ~FileHandler() {                  // destructor
        if (fp) fclose(fp);           // auto cleanup
        cout << "File closed";
    }
};
// Destructor called automatically when object scope ends

Key points:

• Name = ~ClassName()
• No parameters, no return type
• Called in reverse order of construction
• In Java, finalize() plays a similar role (but garbage collector handles most cleanup)

Q20. ⭐ What is multiple inheritance? Why doesn’t Java support it?

Answer: Multiple inheritance — A class inheriting from more than one parent class.

Java doesn’t support multiple inheritance for classes because of the Diamond Problem:

    A
   / \
  B   C
   \ /
    D  ← Which version of A's method should D use?

If B and C both override a method from A, and D inherits from both B and C, it’s ambiguous which version D should call.

Java’s solution: Java allows multiple inheritance through interfaces (since interfaces had no implementation in Java 7; Java 8 default methods have explicit resolution rules).

interface B { default void show() { System.out.println("B"); } }
interface C { default void show() { System.out.println("C"); } }
class D implements B, C {
    public void show() { B.super.show(); }  // explicitly resolve conflict
}

Q21. ⭐ What is the difference between composition and inheritance? When to use which?

Answer:

// Inheritance (IS-A)
class Dog extends Animal { }

// Composition (HAS-A) — preferred over inheritance
class Car {
    private Engine engine;       // Car HAS-A Engine
    private Wheels wheels;
    Car() { engine = new Engine(); wheels = new Wheels(); }
}

Rule: Prefer composition over inheritance (GoF principle). Use inheritance only when there’s a genuine IS-A relationship that won’t change.

Q22. ⭐ What is the concept of encapsulation? How is it achieved in Java?

Answer: Encapsulation = bundling data (fields) and methods that operate on data into a single unit (class), and restricting direct access to the internal state.

Achieved through:

1. Making fields private
2. Providing public getter/setter methods with validation logic

class Employee {
    private String name;
    private double salary;

    public String getName() { return name; }
    public void setName(String name) {
        if (name != null && !name.isEmpty())
            this.name = name;
    }
    public double getSalary() { return salary; }
    public void setSalary(double salary) {
        if (salary > 0) this.salary = salary;    // validation
    }
}

Benefits: Data hiding, controlled access, easier maintenance, increased flexibility.

Q23. ⭐ Is C++ a purely object-oriented language? Is Java?

Answer: C++: NOT purely object-oriented. Reasons:

• You can write functions outside classes
• Has primitive data types (int, char, float) which are not objects
• main() exists outside any class
• Supports procedural programming

Java: NOT purely object-oriented either (despite common belief). Reasons:

• Has primitive data types (int, long, double, boolean) which are not objects
• Static methods can be called without creating objects
• However, Java is MORE object-oriented than C++

Purely OOP languages: Smalltalk, Ruby — where everything including numbers are objects.

Q24. ⭐ What is the difference between a class and an object?

Answer:

// Class — blueprint (defined once)
class Car {
    String brand;
    int speed;
    void drive() { System.out.println("driving " + brand); }
}

// Objects — instances (created many times)
Car c1 = new Car();  c1.brand = "Tesla";
Car c2 = new Car();  c2.brand = "BMW";
// c1 and c2 are separate objects of the same class

🟡 DBMS — Q25 to Q36

Q25. ⭐ What is normalization? Explain 1NF, 2NF, 3NF, and BCNF.

Answer: Normalization organises a database to reduce data redundancy and improve data integrity.

1NF (First Normal Form):

• Atomic values — no multi-valued or composite attributes
• Each column has a single value per row
• Violation: Phone: 9876543210, 9123456789 in one cell

2NF (Second Normal Form):

• Must be 1NF
• No partial dependency — every non-key attribute must depend on the FULL primary key
• Applies only to composite primary keys

3NF (Third Normal Form):

• Must be 2NF
• No transitive dependency — non-key column should NOT depend on another non-key column
• Example violation: EmpID → Dept → DeptLocation (DeptLocation depends on Dept, not EmpID)

BCNF (Boyce-Codd Normal Form):

• Stronger version of 3NF
• For every functional dependency X → Y, X must be a super key

Q26. ⭐ What is the difference between a primary key and a unique key?

Answer:

CREATE TABLE employees (
    emp_id INT PRIMARY KEY,       -- primary key
    email VARCHAR(100) UNIQUE,    -- unique key
    aadhar VARCHAR(12) UNIQUE     -- another unique key
);

Q27. ⭐ What is a foreign key? What is referential integrity?

Answer: A foreign key is a column in one table that references the primary key of another table. It creates a link between two tables.

Referential Integrity ensures that:

• You cannot insert a foreign key value that doesn’t exist in the referenced table
• You cannot delete a primary key row that is referenced by a foreign key (unless CASCADE is set)

CREATE TABLE orders (
    order_id INT PRIMARY KEY,
    customer_id INT,
    FOREIGN KEY (customer_id) REFERENCES customers(id)
        ON DELETE CASCADE     -- delete orders when customer is deleted
        ON UPDATE CASCADE     -- update if customer id changes
);

Q28. ⭐ What are the two integrity rules in DBMS?

Answer: (Actual TCS Prime question — PrepInsta)

1. Entity Integrity Rule: Every table must have a primary key, and the primary key column cannot contain NULL values. Every row must be uniquely identifiable.

2. Referential Integrity Rule: Foreign key values must either:

• Match a primary key value in the referenced table, OR
• Be NULL

This prevents orphaned records — you cannot have an Order referencing a Customer that doesn’t exist.

Q29. ⭐ What is a transaction in DBMS? What are ACID properties?

Answer: A transaction is a sequence of database operations treated as a single logical unit.

A — Atomicity: All-or-nothing. If any step fails, the entire transaction rolls back. Example: Bank transfer — deduct from A AND credit to B must both succeed or both fail.

C — Consistency: Transaction takes DB from one valid state to another, maintaining all constraints.

I — Isolation: Concurrent transactions don’t interfere. Intermediate states are invisible to others.

D — Durability: Once committed, changes are permanent — survive system crashes (via write-ahead log).

Q30. ⭐ What is a view in SQL? What are its advantages?

Answer: A view is a virtual table based on a SELECT query. It doesn’t store data physically — it stores the query definition.

-- Create a view
CREATE VIEW high_earners AS
SELECT name, department, salary
FROM employees
WHERE salary > 80000;

-- Use it like a table
SELECT * FROM high_earners WHERE department = 'Engineering';

Advantages:

• Security — hide sensitive columns from users
• Simplification — complex queries stored once, reused as simple table
• Data abstraction — underlying table structure can change without affecting users
• Aggregation — precompute frequently needed aggregations

Q31. ⭐ What is the difference between clustered and non-clustered index?

Answer:

-- Clustered (primary key creates it automatically)
CREATE TABLE emp (id INT PRIMARY KEY, name VARCHAR(50));

-- Non-clustered
CREATE INDEX idx_name ON emp(name);
CREATE INDEX idx_dept_sal ON emp(department, salary);  -- composite

Q32. ⭐ What is a trigger in SQL? When is it used?

Answer: A trigger is a stored procedure that automatically executes in response to a DML event (INSERT, UPDATE, DELETE) on a table.

-- Trigger: log salary changes
CREATE TRIGGER log_salary_change
AFTER UPDATE ON employees
FOR EACH ROW
BEGIN
    INSERT INTO salary_audit(emp_id, old_salary, new_salary, changed_at)
    VALUES (OLD.id, OLD.salary, NEW.salary, NOW());
END;

Types:

• BEFORE / AFTER triggers
• ROW-level / Statement-level triggers

Use cases: Audit logging, enforcing business rules, auto-updating derived columns, cascading changes.

Q33. ⭐ What is a stored procedure? How is it different from a function?

Answer:

-- Stored procedure
CREATE PROCEDURE get_employees_by_dept(IN dept_name VARCHAR(50))
BEGIN
    SELECT * FROM employees WHERE department = dept_name;
END;
CALL get_employees_by_dept('Engineering');

-- Function
CREATE FUNCTION get_annual_salary(monthly DECIMAL(10,2))
RETURNS DECIMAL(10,2)
BEGIN
    RETURN monthly * 12;
END;
SELECT name, get_annual_salary(salary) FROM employees;

Q34. ⭐ What is a cursor in SQL?

Answer: A cursor is a database object used to retrieve and process rows one at a time from a result set (like a pointer/iterator for query results).

DECLARE emp_cursor CURSOR FOR
    SELECT name, salary FROM employees WHERE dept = 'IT';

DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN emp_cursor;

read_loop: LOOP
    FETCH emp_cursor INTO v_name, v_salary;
    IF done THEN LEAVE read_loop; END IF;
    -- process each row
    SET v_salary = v_salary * 1.10;
    UPDATE employees SET salary = v_salary WHERE name = v_name;
END LOOP;

CLOSE emp_cursor;

When to use: When row-by-row processing is required and set-based operations are not possible. Generally avoided due to performance overhead.

Q35. ⭐ What is ER (Entity-Relationship) model?

Answer: An ER model is a conceptual diagram that describes the structure of a database using entities, attributes, and relationships.

Key components:

• Entity — Real-world object (Employee, Product, Department)
• Attribute — Property of entity (Name, Age, Salary)
• Key Attribute — Uniquely identifies entity (EmployeeID)
• Relationship — Association between entities (Employee WORKS_IN Department)
• Cardinality — 1:1, 1:M, M:M relationships

Types of entities:

• Strong entity — Has its own primary key
• Weak entity — Depends on another entity (OrderItem depends on Order)

Q36. ⭐ What is denormalization? When would you use it?

Answer: Denormalization is the process of intentionally adding redundancy to a database that was previously normalized, to improve read performance.

When to use:

• Read-heavy systems where query speed matters more than storage
• Data warehouses and reporting databases
• When complex JOINs across many tables are too slow

-- Normalized: need JOIN to get product name with order
SELECT o.id, p.name FROM orders o JOIN products p ON o.product_id = p.id;

-- Denormalized: product_name stored directly in orders table
SELECT id, product_name FROM orders;  -- no JOIN needed, faster

Trade-off: Denormalization sacrifices storage efficiency and data consistency for query speed.

🟢 OPERATING SYSTEMS — Q37 to Q46

Q37. ⭐ What is an operating system? What are its main functions?

Answer: An OS is system software that manages hardware resources and provides services to application programs. It acts as an interface between user and hardware.

Main functions:

• Process Management — Create, schedule, terminate processes
• Memory Management — Allocate/deallocate RAM, virtual memory, paging
• File System Management — Organise, store, retrieve files
• Device Management — Manage I/O devices via device drivers
• Security & Access Control — Authentication, permissions, user isolation
• Networking — Manage network connections and protocols

Examples: Windows, Linux, macOS, Android, iOS

Q38. ⭐ What is the difference between a process and a thread?

Answer:

Q39. ⭐ What is deadlock? What are the four Coffman conditions?

Answer: A deadlock is a situation where two or more processes wait for each other indefinitely, each holding a resource the other needs.

Four Coffman Conditions (ALL must hold for deadlock):

1. Mutual Exclusion — At least one resource is held in non-sharable mode
2. Hold and Wait — A process holds at least one resource while waiting for others
3. No Preemption — Resources cannot be forcibly taken from a process
4. Circular Wait — A circular chain of processes, each waiting for a resource held by the next

Prevention: Break any ONE condition:

• Use resource ordering to prevent circular wait (most practical)
• Allow preemption
• Use Banker’s Algorithm for deadlock avoidance

Q40. ⭐ What is paging in OS?

Answer: Paging is a memory management scheme that eliminates the need for contiguous physical memory allocation.

• Logical memory (process view) is divided into equal-sized blocks called pages
• Physical memory is divided into equal-sized blocks called frames
• OS maintains a Page Table mapping pages to frames

Process Address Space:     Physical Memory (RAM):
Page 0 → Frame 3           Frame 0: OS
Page 1 → Frame 7           Frame 1: ...
Page 2 → Frame 2           Frame 2: Process Page 2
                           Frame 3: Process Page 0

Advantage: Eliminates external fragmentation. Disadvantage: Internal fragmentation possible; page table overhead.

Q41. ⭐ What is the Round Robin scheduling algorithm?

Answer: (Actual TCS Prime question — PrepInsta)

Round Robin (RR) is a CPU scheduling algorithm designed for time-sharing systems.

• Each process gets a fixed time slot called time quantum (typically 10–100ms)
• After the quantum expires, the process is preempted and added back to the end of the ready queue
• Next process in queue gets the CPU

Time Quantum = 3ms
Processes: P1(6ms), P2(4ms), P3(2ms)

Timeline:
P1(3) → P2(3) → P3(2) → P1(3) → P2(1) = Done

Advantage: Fair, no starvation. Disadvantage: High context switching overhead if quantum is too small; long waiting time if quantum is too large.

Q42. ⭐ What is virtual memory? What is thrashing?

Answer: Virtual memory is a technique that allows executing processes that may not be completely in memory. It uses disk space as an extension of RAM.

When a process references a page not in RAM → Page Fault → OS brings the page from disk (page swapping).

Thrashing occurs when a system spends more time swapping pages in and out of memory than executing actual instructions.

Causes: Too many processes running simultaneously with insufficient RAM. Solution: Reduce degree of multiprogramming, increase RAM, use working set model.

Q43. ⭐ What is the difference between internal and external fragmentation?

Answer:

Internal Fragmentation — Wasted space inside allocated memory blocks. Occurs in fixed-size allocation (paging). If a process needs 18KB and gets 20KB pages → 2KB wasted inside.

External Fragmentation — Wasted space outside allocated memory — enough total free memory exists but not as a contiguous block. Occurs in variable-size allocation (segmentation).

External: [USED 10KB] [FREE 5KB] [USED 8KB] [FREE 5KB] [USED 6KB]
→ 10KB total free but cannot allocate 10KB contiguous block

Internal: Process needs 13KB, page size = 4KB
→ Allocated 4 pages = 16KB → 3KB wasted inside

Q44. ⭐ What are semaphores? What is the difference between binary and counting semaphores?

Answer: A semaphore is a synchronisation primitive (integer variable) used to control access to shared resources in a concurrent system.

Operations:

• wait(S) / P(S): Decrements S; blocks if S = 0
• signal(S) / V(S): Increments S; wakes up blocked process

Binary Semaphore (Mutex):

• Value: 0 or 1 only
• Used for mutual exclusion (one process at a time)
• Equivalent to a lock

Counting Semaphore:

• Value: 0 to N
• Controls access to a resource pool of N instances
• Example: DB connection pool of 10 connections → semaphore initialised to 10

Q45. ⭐ What is context switching?

Answer: Context switching is the process of saving the state of a currently running process and loading the state of the next process so the CPU can switch between processes.

State saved/restored (Process Control Block — PCB):

• Program Counter (next instruction address)
• CPU registers
• Memory management info
• Process state (running, waiting, ready)

Cost: Context switching is pure overhead — CPU does no useful work during the switch. High frequency switching wastes CPU cycles. This is why threads are preferred over processes for concurrency (cheaper context switch).

Q46. ⭐ What is the difference between multiprogramming, multitasking, and multiprocessing?

Answer:

🔵 COMPUTER NETWORKS — Q47 to Q56

Q47. ⭐ Explain the OSI model with all 7 layers.

Answer:

Memory trick: “All People Seem To Need Data Processing” (bottom to top: Physical, Data Link, Network, Transport, Session, Presentation, Application)

Q48. ⭐ What is the difference between TCP and UDP?

Answer:

TCP 3-way handshake:
Client → SYN → Server
Client ← SYN-ACK ← Server
Client → ACK → Server
[Connection established]

Q49. ⭐ What is an IP address? What is the difference between IPv4 and IPv6?

Answer: An IP address is a numerical label assigned to each device on a network that uses the Internet Protocol for communication.

Q50. ⭐ What is a firewall? How is it different from IDS/IPS?

Answer: (Actual TCS Prime question — PrepInsta)

Firewall — Network security device that monitors and controls incoming/outgoing traffic based on predefined rules. Operates at Layer 3/4 of OSI. Blocks/allows packets based on IP, port, protocol.

IDS (Intrusion Detection System) — Monitors network traffic for suspicious activity and alerts administrators. Passive — doesn’t block.

IPS (Intrusion Prevention System) — Like IDS but actively blocks threats in real-time. Inline device.

Q51. ⭐ What is DNS? How does it work?

Answer: DNS (Domain Name System) translates human-readable domain names (www.google.com) into IP addresses (142.250.195.36).

DNS Resolution process:

1. User types www.google.com
2. Browser checks local cache — if found, done
3. Query goes to Recursive Resolver (usually ISP’s DNS)
4. Resolver queries Root Name Server → points to .com TLD server
5. TLD server → points to google.com Authoritative Name Server
6. Authoritative server → returns IP address 142.250.195.36
7. Browser connects to that IP

DNS record types: A (IPv4), AAAA (IPv6), CNAME (alias), MX (mail), TXT (verification)

Q52. ⭐ What is the difference between HTTP and HTTPS?

Answer:

How HTTPS works:

1. Client requests HTTPS connection
2. Server sends SSL certificate
3. Client verifies certificate (CA signed?)
4. Client generates session key, encrypts with server’s public key
5. Server decrypts with private key
6. Encrypted communication begins using session key

Q53. ⭐ What is a MAC address? How is it different from an IP address?

Answer:

Q54. ⭐ What is the difference between a router, switch, and hub?

Answer:

Q55. ⭐ What is the concept of subnetting?

Answer: Subnetting is the process of dividing a large network into smaller sub-networks (subnets) to improve performance, security, and address management.

CIDR Notation: 192.168.1.0/24

• /24 means 24 bits for network, 8 bits for hosts
• Hosts = 2^8 – 2 = 254 usable host addresses

Subnet Mask: 255.255.255.0 (for /24)

Why subnet?

• Reduces broadcast traffic
• Improves security (isolate departments)
• More efficient IP address usage

Network: 192.168.1.0/24 → split into 4 subnets:
Subnet 1: 192.168.1.0/26   (62 hosts) → Engineering
Subnet 2: 192.168.1.64/26  (62 hosts) → Marketing
Subnet 3: 192.168.1.128/26 (62 hosts) → Finance
Subnet 4: 192.168.1.192/26 (62 hosts) → HR

Q56. ⭐ What happens when you type www.google.com in your browser and press Enter?

Answer: (Exact TCS Digital question — very popular)

1. DNS lookup — Browser checks cache → OS cache → Router cache → ISP DNS → Root/TLD/Authoritative servers → gets IP 142.250.x.x
2. TCP 3-way handshake — SYN → SYN-ACK → ACK with server IP:443
3. TLS/SSL handshake — Certificate exchange, session key negotiation (for HTTPS)
4. HTTP GET request — GET / HTTP/1.1 Host: www.google.com
5. Server processing — Web server receives request → application server processes → DB queries if needed
6. HTTP response — Server sends HTML, CSS, JS, images
7. Browser rendering — Parses HTML → builds DOM → processes CSS → executes JS → paints page
8. Connection — TCP kept alive (keep-alive header) for subsequent resource requests

💻 CODING ON PAPER — Q57 to Q70

Q57. ⭐ Write a program to reverse a linked list. (Actual TCS Prime — paper coding)

Answer:

class Node:
    def __init__(self, val):
        self.val = val
        self.next = None

def reverse(head):
    prev = None
    curr = head
    while curr:
        nxt = curr.next
        curr.next = prev
        prev = curr
        curr = nxt
    return prev   # new head

# Time: O(n)  Space: O(1)

Q58. ⭐ Write a program to find if a number is prime. (Actual TCS TR — paper coding)

Answer:

def is_prime(n):
    if n < 2:
        return False
    if n == 2:
        return True
    if n % 2 == 0:
        return False
    for i in range(3, int(n**0.5) + 1, 2):
        if n % i == 0:
            return False
    return True

# Optimised: only check up to sqrt(n)
# Time: O(sqrt(n))

Q59. ⭐ Write a program to find all words with more than 8 characters in a sentence. (Actual TCS Digital — paper coding)

Answer:

sentence = "TCS is a multinational technology company headquartered in Mumbai"
result = [w for w in sentence.split() if len(w) > 8]
print(result)
# Output: ['multinational', 'technology', 'headquartered']

Q60. ⭐ Write a program to find the frequency of each character in a string. (Actual TCS TR — paper coding)

Answer:

def char_frequency(s):
    freq = {}
    for ch in s:
        freq[ch] = freq.get(ch, 0) + 1
    for ch, count in sorted(freq.items()):
        print(f"'{ch}': {count}")

char_frequency("programming")
# 'a': 1, 'g': 2, 'i': 1, 'm': 2, 'n': 1, 'o': 1, 'p': 1, 'r': 2

Q61. ⭐ Write a program to find the square root of a number without using sqrt(). (Actual TCS Prime — exact PYQ)

Answer:

def sqrt_binary(n):
    if n < 2:
        return n
    low, high, ans = 1, n // 2, 0
    while low <= high:
        mid = (low + high) // 2
        if mid * mid == n:
            return mid
        elif mid * mid < n:
            ans = mid
            low = mid + 1
        else:
            high = mid - 1
    return ans   # floor of sqrt

print(sqrt_binary(6096))  # 78
print(sqrt_binary(25))    # 5
# Time: O(log n)

Q62. ⭐ Print a star pattern (N rows triangle). (Actual TCS TR — paper coding)

Answer:

n = 5
# Right triangle
for i in range(1, n + 1):
    print('* ' * i)

# Output:
# *
# * *
# * * *
# * * * *
# * * * * *

# Pyramid pattern
for i in range(1, n + 1):
    print(' ' * (n - i) + '* ' * i)

Q63. ⭐ Write a program to check if a string is a palindrome. (Actual TCS TR)

Answer:

def is_palindrome(s):
    s = s.lower().replace(' ', '')   # clean input
    return s == s[::-1]

print(is_palindrome("racecar"))   # True
print(is_palindrome("hello"))     # False
print(is_palindrome("A man a plan a canal Panama"))  # True

Q64. ⭐ Write code to find the length of the Longest Palindromic Subsequence. (Actual TCS Prime — exact PYQ from GeeksforGeeks)

Answer:

def lps(s):
    n = len(s)
    t = s[::-1]                    # reverse = LCS trick
    dp = [[0]*(n+1) for _ in range(n+1)]
    for i in range(1, n+1):
        for j in range(1, n+1):
            if s[i-1] == t[j-1]:
                dp[i][j] = dp[i-1][j-1] + 1
            else:
                dp[i][j] = max(dp[i-1][j], dp[i][j-1])
    return dp[n][n]

print(lps("bbabcbcab"))  # 7 ("babcbab")
# Time: O(n^2)  Space: O(n^2)

Q65. ⭐ Write code to create an upper triangular matrix. (Actual TCS Prime — exact coding PYQ)

Answer:

def upper_triangular(matrix):
    n = len(matrix)
    for i in range(n):
        for j in range(n):
            if j < i:
                matrix[i][j] = 0
    return matrix

mat = [[1,2,3],[4,5,6],[7,8,9]]
result = upper_triangular(mat)
for row in result:
    print(row)
# [1, 2, 3]
# [0, 5, 6]
# [0, 0, 9]

Q66. ⭐ Write code for Binary Search. (Actual TCS Digital TR — paper coding)

Answer:

def binary_search(arr, target):
    low, high = 0, len(arr) - 1
    while low <= high:
        mid = (low + high) // 2
        if arr[mid] == target:
            return mid        # found at index mid
        elif arr[mid] < target:
            low = mid + 1     # search right half
        else:
            high = mid - 1    # search left half
    return -1                 # not found

arr = [1, 3, 5, 7, 9, 11, 13]
print(binary_search(arr, 7))   # 3
print(binary_search(arr, 6))   # -1
# Time: O(log n)

Q67. ⭐ Write code to detect a cycle in a linked list. (Actual TCS Prime — paper coding)

Answer:

class Node:
    def __init__(self, val):
        self.val = val
        self.next = None

def has_cycle(head):
    slow = fast = head
    while fast and fast.next:
        slow = slow.next           # move 1 step
        fast = fast.next.next     # move 2 steps
        if slow == fast:
            return True           # cycle detected
    return False

# Floyd's Tortoise and Hare Algorithm
# Time: O(n)  Space: O(1)

Q68. ⭐ Write code to implement a stack using an array. (Actual TCS Digital TR)

Answer:

class Stack:
    def __init__(self, capacity):
        self.stack = []
        self.capacity = capacity

    def push(self, val):
        if len(self.stack) == self.capacity:
            print("Stack Overflow")
            return
        self.stack.append(val)

    def pop(self):
        if not self.stack:
            print("Stack Underflow")
            return None
        return self.stack.pop()

    def peek(self):
        return self.stack[-1] if self.stack else None

    def is_empty(self):
        return len(self.stack) == 0

s = Stack(3)
s.push(10); s.push(20); s.push(30)
print(s.pop())   # 30
print(s.peek())  # 20

Q69. ⭐ Write a program to demonstrate abstraction using OOP. (Actual TCS Digital — exact coding question)

Answer:

from abc import ABC, abstractmethod

class Shape(ABC):             # Abstract class
    @abstractmethod
    def area(self):           # Abstract method
        pass

    @abstractmethod
    def perimeter(self):
        pass

    def describe(self):       # Concrete method
        print(f"Area: {self.area():.2f}, Perimeter: {self.perimeter():.2f}")

class Circle(Shape):
    def __init__(self, r):
        self.r = r
    def area(self):
        return 3.14 * self.r ** 2
    def perimeter(self):
        return 2 * 3.14 * self.r

class Rectangle(Shape):
    def __init__(self, l, w):
        self.l, self.w = l, w
    def area(self):
        return self.l * self.w
    def perimeter(self):
        return 2 * (self.l + self.w)

Circle(5).describe()       # Area: 78.50, Perimeter: 31.40
Rectangle(4, 6).describe() # Area: 24.00, Perimeter: 20.00

Q70. ⭐ Write code to find the Fibonacci series using both recursion and dynamic programming. (Actual TCS TR — exact PYQ)

Answer:

# Method 1: Recursion (simple, exponential time)
def fib_recursive(n):
    if n <= 1: return n
    return fib_recursive(n-1) + fib_recursive(n-2)
# Time: O(2^n) — very slow for large n

# Method 2: Dynamic Programming (memoisation)
from functools import lru_cache
@lru_cache(maxsize=None)
def fib_memo(n):
    if n <= 1: return n
    return fib_memo(n-1) + fib_memo(n-2)
# Time: O(n)  Space: O(n)

# Method 3: DP Tabulation (most efficient)
def fib_dp(n):
    if n <= 1: return n
    dp = [0] * (n + 1)
    dp[1] = 1
    for i in range(2, n + 1):
        dp[i] = dp[i-1] + dp[i-2]
    return dp[n]
# Time: O(n)  Space: O(n)

print([fib_dp(i) for i in range(10)])
# [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

🧠 BEHAVIOURAL + SCENARIO — Q71 to Q82

Q71. ⭐ Tell me about a time you failed. What did you learn?

Answer (STAR): Situation: In my 3rd semester, I was overconfident going into the database design exam and didn’t revise thoroughly.

Task: Score well and understand relational design concepts deeply.

Action: I failed to account for a complex normalisation question. After the exam, I didn’t make excuses — I revisited the entire topic, built a small database project from scratch, and taught it to a classmate to reinforce my understanding.

Result: In my next related exam I scored 92%. More importantly, DBMS became one of my strongest interview topics. Failure taught me that confidence without preparation is arrogance.

Q72. ⭐ Describe a project you are most proud of. Walk me through it technically.

Answer (Framework):

1. Problem statement — What problem did it solve?
2. Tech stack — Languages, frameworks, databases used
3. Architecture — How the system was designed (frontend → backend → DB)
4. Your specific contribution — Not the team’s work, YOUR work
5. Challenges faced — Technical hurdles and how you overcame them
6. Outcome/impact — Results, users, performance improvements

Sample opening: “My most proud project is a real-time attendance management system I built using Flask, SQLite, and OpenCV for face recognition. The problem was our college’s manual attendance was error-prone and time-consuming. I designed the database schema, built the REST API, and integrated face detection — which was my biggest challenge because accuracy dropped in low-light conditions. I solved it by adding image preprocessing…”

Q73. ⭐ How do you handle disagreements with teammates or a senior?

Answer: “I believe disagreements are healthy when handled constructively. My approach is to first ensure I fully understand the other person’s point — I listen completely before responding. If I disagree with a senior, I frame it professionally: ‘I see your point, may I share a concern?’ and present data or reasoning to support my view. If the disagreement is with a peer, I suggest we take both approaches to a smaller test scenario and let results decide. I’ve found that separating the idea from the person makes technical disagreements much easier to resolve. Ultimately, I defer to hierarchy when a decision must be made, but I always ensure my concern is documented.”

Q74. ⭐ Give an example where you showed leadership.

Answer (STAR): “During our final year project, our team of four had unclear responsibilities and we were behind schedule two weeks before the deadline. I recognised that nobody had taken ownership, so I stepped up — I called a meeting, mapped out remaining tasks, assigned them based on each person’s strengths, and set daily check-in deadlines. I also paired the weakest team member with myself for the database component so nothing would block progress. We submitted on time with a complete feature set. Our guide complimented the project’s quality. This taught me that leadership isn’t about authority — it’s about taking responsibility when others hesitate.”

Q75. ⭐ What would you do if you were given an impossible deadline?

Answer: “My first step would be to break the task down and get a realistic estimate of what’s achievable. I would immediately communicate transparently with my manager: ‘Here is what can be delivered by X date and here is what cannot — what is the priority?’ I would not promise something I cannot deliver and then fail silently. I believe setting honest expectations early is far better than delivering incomplete work at the last minute. I would also look for ways to optimise — reduce scope, automate repetitive tasks, or ask for temporary resources. If the deadline genuinely cannot move, I would work extended hours for a short sprint but flag that this isn’t sustainable long-term.”

Q76. ⭐ You have a bug in production that is affecting thousands of users. What do you do?

Answer: “Step one is immediate containment — if there’s a rollback available, I roll back to the last stable version while we investigate. If not, I check if the bug can be patched with a hotfix in under an hour. Step two is identification — I look at logs, error reports, and replicate the issue locally. Step three is communication — I inform the team lead immediately and provide a clear status update. I never go silent during an incident. Step four is fix and test — write the fix, test it in staging, then deploy with monitoring. Step five is post-mortem — after resolution, I document what went wrong, why, and what preventive measure stops it from happening again.”

Q77. ⭐ How do you prioritise tasks when you have multiple deadlines?

Answer: “I use a combination of urgency and importance — the Eisenhower Matrix approach. I first identify what’s truly urgent AND important (do immediately), what’s important but not urgent (schedule), what’s urgent but not important (delegate if possible), and what’s neither (drop or defer). I also consider dependencies — which task blocks others. I communicate early if I think something is at risk. In practice, I maintain a task list with deadlines and estimate time per task at the start of each day. This visual clarity prevents the feeling of being overwhelmed and ensures I’m making conscious priority decisions rather than reactive ones.”

Q78. ⭐ Tell me about a time you had to learn something very quickly.

Answer (STAR): “Situation: During my internship, I was suddenly assigned to a task that required React.js — a framework I hadn’t formally learned.

Task: Build a dashboard component in one week.

Action: I spent the first day going through the official React docs and building a mini to-do app. On day 2, I started the actual task with a simplified scope and gradually added complexity. I asked targeted questions to senior developers rather than general ‘how does React work’ questions.

Result: I delivered the dashboard component within 5 days. My manager said it was ‘production-ready’ with minor tweaks. This experience reinforced my belief that the fastest way to learn a technology is to build something real with it immediately.”

Q79. ⭐ What is your biggest strength? How does it apply to software engineering?

Answer: “My biggest strength is structured problem decomposition — the ability to take a complex problem and break it into smaller, manageable parts before writing a single line of code. In software engineering, this directly maps to system design, where rushing to code without clarity creates technical debt. When I face a difficult coding problem, I spend the first 20% of the time understanding and decomposing it — drawing the flow, identifying edge cases, planning the data structures — before I write anything. This approach consistently produces cleaner solutions. It also helps me communicate clearly with non-technical stakeholders, because I can translate a complex system into understandable components.”

Q80. ⭐ If a team member is not contributing and it’s affecting your project, what will you do?

Answer: “I would first try to understand if there’s a genuine reason — personal issues, lack of clarity on tasks, skill gaps. I would have a private, non-judgmental conversation: ‘I noticed you’ve been quiet on the project — is there anything I can help with?’ Many times, people are struggling silently. If it’s a skills gap, I would offer to pair with them. If they are simply disengaged, I would have an honest conversation: ‘Our deadline is X and we need Y from you specifically.’ If the issue persists and starts genuinely risking the project, I would escalate to the team lead — not to get them in trouble, but because the project’s success and the entire team’s effort deserves protection.”

Q81. ⭐ Are you comfortable working in a team or alone? Which do you prefer?

Answer: “I work effectively in both environments and adapt based on what the situation demands. For creative and exploratory tasks — like architecting a solution or debugging a tricky problem — I do my best thinking independently. For execution, review, and iteration — sharing code, discussing approaches, catching each other’s blind spots — a team is far superior. In a professional setting, both skills are essential. My internship gave me experience in a cross-functional team of 6, and I’ve also completed significant solo projects. I’m genuinely comfortable in both modes.”

Q82. ⭐ How do you stay updated with technology trends?

Answer: “I have a structured approach. For daily updates I follow specific newsletters — TLDR Tech, The Pragmatic Engineer. For deep dives I use official documentation, YouTube channels like Fireship, and read tech blogs from companies like Netflix Engineering, Uber Engineering, and Google Research. I try to build something small with any new technology I read about — theory without practice is forgettable. I’m also active on GitHub, where I explore popular open-source repositories to understand how production-level code is structured. Recently I’ve been tracking developments in vector databases and RAG systems for AI applications.”

📊 MANAGERIAL ROUND — Q83 to Q91

Q83. ⭐ What is your opinion on Work From Home vs Work From Office?

Answer: “Both modes have genuine strengths. Office work is invaluable early in a career — the informal knowledge transfer, mentorship, and cultural absorption that happen organically in an office are very difficult to replicate remotely. For a fresher joining TCS, the office environment would accelerate my learning significantly. Remote work, on the other hand, offers focused deep-work time, eliminates commute, and can be more productive for autonomous tasks. I believe a hybrid model captures the best of both. I am completely adaptable to whatever model TCS requires for my project, and I’ve already practiced self-discipline through online learning and solo project work.”

Q84. ⭐ If we give you a technology you have never worked with, how will you handle it?

Answer: “I would treat it as an opportunity rather than a challenge. My approach is: first, spend a day with the official documentation to understand the core concepts and mental model of the technology. Second, build the smallest possible working program — even a ‘Hello World’ equivalent for that technology — to break the psychological barrier. Third, attempt a simplified version of the actual task. Fourth, use targeted questions to seniors or communities like Stack Overflow for specific blockers — never general ‘how does X work’ questions.

I learned Python this way in three weeks while already knowing C and Java. The underlying concepts — variables, loops, functions, OOP — transfer across languages. What changes is syntax and idioms, and those are learnable quickly with practice.”

Q85. ⭐ If we downgrade your offer from Digital to Ninja, would you accept?

Answer: “I appreciate you being direct with this question. I’ll be equally direct — my preparation, the profile I interviewed for, and my career expectations are aligned with the Digital profile. I wouldn’t want to start my career at TCS under the wrong expectations on either side.

That said, I genuinely want to work at TCS. If there is a clear path and timeline to transition to Digital based on performance, and if the work I’d be doing as a Ninja fresher gives me meaningful exposure, I’d want to understand that roadmap clearly before deciding. I believe in making informed decisions rather than emotional ones.”

Q86. ⭐ You are from ECE. Why did you choose IT over core electronics?

Answer: “ECE gave me a strong foundation in systems thinking, embedded logic, and how hardware and software interact at the fundamental level. During my second year, I built a project that combined sensors with a web dashboard — that intersection of hardware and software was what drew me to programming. I realised that software could reach millions of people in a way that hardware products alone couldn’t.

Since then, I’ve deliberately built my software skills — DSA, web development, databases, and system design. My ECE background is actually an advantage in IT, especially for roles involving IoT, embedded systems, or cloud-connected hardware. I see it as a complement, not a compromise.”

Q87. ⭐ What do you know about TCS’s business and current initiatives?

Answer: “TCS is India’s largest IT services company by market capitalisation — approximately $168 billion as of early 2025 — and consistently one of the top 10 IT companies globally. TCS operates in 46 countries with over 600,000 employees.

Currently, TCS is heavily investing in AI through its TCS.AI platform, offering GenAI services to enterprise clients. Their TCS Pace innovation hubs focus on quantum computing, cloud, and AI research. TCS has significant presence in BFSI, healthcare, retail, and government sectors. Recent wins include major cloud transformation deals with European financial institutions and a long-term partnership with Jaguar Land Rover. Their iON platform handles large-scale digital assessments, and BaNCS is a leading banking product used globally.”

Q88. ⭐ If your manager gives you a task you disagree with technically, what will you do?

Answer: “My first step is to make sure I fully understand the reasoning — sometimes a technical decision that looks wrong has context I’m missing. I would ask: ‘Could you help me understand the constraints driving this approach?’ If after understanding their perspective I still have a genuine concern, I would raise it professionally: ‘I understand your approach. I have a concern about X — may I share it?’ and back it with data, benchmarks, or a concrete example.

If my concern is heard but overruled, I’d accept the decision and execute it to the best of my ability — expressing disagreement and then delivering poorly is worse than just complying. However, I would document my concern so if an issue arises later there’s a record. Healthy technical disagreement expressed respectfully is what separates good engineers from yes-men.”

Q89. ⭐ How would you handle a very difficult client who is never satisfied?

Answer: “Difficult clients are usually driven by unmet expectations, not personality. My approach would be to first understand exactly what ‘satisfied’ means to them — what specific outcome would make them happy? Often, frustration comes from vague requirements that led to vague delivery.

I would set up a structured communication cadence — weekly updates with concrete metrics, not general ‘we’re working on it’ updates. I would involve them in milestone reviews so they see progress incrementally rather than only at final delivery. If expectations are genuinely unreasonable, I would involve my manager early — never promise what cannot be delivered just to keep peace in the short term. Ultimately, a good client relationship is built on predictability and honesty, not just saying yes.”

Q90. ⭐ Where do you see yourself in 5 years?

Answer: “In five years I want to be a technically strong engineer with deep expertise in at least one domain — my current interest is in cloud-native systems and distributed architecture. I want to have contributed meaningfully to at least 2–3 end-to-end enterprise projects, preferably with client-facing exposure. At TCS, that would put me at the IT Analyst or Assistant Consultant level on the technical track.

Beyond titles, I want to be someone my team comes to for technical guidance — not because I’m the most senior, but because I’ve consistently delivered quality work and mentored others. I’m committed to continuous learning through TCS’s internal training platforms and relevant cloud certifications.”

Q91. ⭐ What motivates you when work becomes repetitive or boring?

Answer: “I look for the hidden learning within repetition. Even in repetitive tasks, there’s usually a way to optimise, automate, or refactor — finding that keeps me engaged. If I’m doing the same data transformation daily, I’ll write a script that does it in seconds. That’s how many great tools get built.

If the task is genuinely unavoidable and repetitive with no room for optimisation, I stay motivated by connecting it to the bigger outcome — ‘this report I’m generating matters to the client’s decision-making.’ I’m also honest with myself — if I’ve been on the same work for a long time with no growth, I’d have a conversation with my manager about new opportunities, because intellectual stagnation doesn’t serve either me or the company.”

🤝 HR + PERSONAL — Q92 to Q100

Q92. ⭐ Why should we hire you?

Answer: “You should hire me because I bring three things that matter specifically for TCS Digital: technical depth in the areas you test for — OOPs, DSA, databases, and systems — demonstrated through my consistent preparation and [specific project/achievement]. Second, I have a genuine curiosity about technology that means I’ll keep learning without being pushed to. Third, I communicate well — I can explain technical concepts to non-technical people, which matters in a client-facing organisation like TCS.

I’m not just looking for a job. I want to build a career at TCS, and I’ve been deliberately preparing for this profile, not applying everywhere and hoping something sticks.”

Q93. ⭐ What is your biggest weakness?

Answer: “My biggest weakness is that I sometimes over-engineer solutions — I tend to think about edge cases and scalability even when the immediate requirement doesn’t need them. This can slow down delivery of simple tasks.

I’ve been actively working on this by setting internal scope boundaries before I start coding: ‘For this task, good enough is X — don’t go beyond it unless asked.’ This has significantly improved my delivery speed. I’ve learned that premature optimisation, as the saying goes, is the root of all evil — there’s a time for robustness and a time for speed.”

Q94. ⭐ Tell me about yourself.

Answer (Structure): “My name is [Name]. I’m a [Branch] engineering graduate from [College]. I chose engineering because [genuine reason], and I gravitated toward software during [specific moment/project].

Technically, I’m strongest in [2–3 skills], and I have hands-on experience through [project/internship] where I [specific achievement]. My most meaningful technical work was [one project], where I [what you built, what problem it solved].

Beyond academics, I [relevant extra-curricular that shows discipline or curiosity]. I applied to TCS Digital specifically because [genuine specific reason related to TCS’s work]. I’m excited about the opportunity to contribute to [specific TCS domain/project type].”

Q95. ⭐ Do you have any other offer? How are you deciding between companies?

Answer: “Yes, I have [/I’m in the process with] [Company X]. My decision criteria are: the quality of technical work I’d be doing in the first 2 years, the learning infrastructure available, the company’s scale and global presence, and the team culture.

TCS stands out because of its scale — working on systems that serve millions of users is genuinely different from smaller environments, and that exposure early in a career is invaluable. The TCS Digital profile specifically, with its focus on emerging technologies, aligns with the kind of engineering I want to do.

I haven’t decided yet but TCS Digital is my top preference.”

Q96. ⭐ Are you comfortable with night shifts or extended working hours when required?

Answer: “Yes, I understand that the nature of enterprise IT delivery — especially with global clients across time zones — sometimes requires flexibility in working hours. I’m comfortable with that, especially for time-bound deliverables like go-live support or production incidents. I believe this kind of commitment is part of what makes a professional reliable.

That said, I also value sustainable work practices for long-term productivity. I’d aim to ensure that extended hours are the exception for genuine business needs rather than a substitute for poor planning. I’m committed to doing what the role requires.”

Q97. ⭐ How do you rate yourself in your favourite programming language on a scale of 1–10?

Answer: “I’d rate myself a 7.5 in Python — my strongest language. I’m very comfortable with core Python: data structures, OOP principles, file handling, generators, decorators, and standard libraries. I’ve used it for [projects].

I rate myself 7.5 and not higher because there are areas I’m still actively developing — asynchronous programming with asyncio, metaclasses, and some performance profiling tools. I believe a 9 or 10 would mean there’s nothing left to learn, which is never true in any technology. I prefer honest self-assessment — I know what I know and I know what I don’t.”

Q98. ⭐ What are your hobbies? How do they relate to your professional life?

Answer: “Outside of academics, I enjoy [genuine hobby]. If it’s technical: ‘I enjoy contributing to open-source projects on GitHub — it has taught me how to read and understand codebases I didn’t write, which is one of the most underrated professional skills.’ Or if non-technical: ‘I play chess, which has strengthened my ability to think multiple steps ahead before acting — something I directly apply when designing system architecture or debugging complex problems.’

[Connect the hobby to a professional trait — discipline, problem-solving, creativity, communication.] I believe who you are outside work shapes how you work, and I try to bring that intentionality to both.”

Q99. ⭐ Do you have any questions for us?

Answer: “Yes, I have three:

First — What does the onboarding and initial training journey look like for a Digital hire? How quickly would I be expected to work on client-facing projects?

Second — What technologies or domains are TCS Digital fresh hires currently being oriented toward — are there specific cloud platforms, AI stacks, or industry verticals that are growing?

Third — How does TCS evaluate performance during the first year for fresher engineers? What does a strong first-year trajectory look like from your observation?”

(Never ask about salary, leave policy, or work hours in the first interview.)

Q100. ⭐ What is the current market cap of TCS? Tell me something recent about TCS.

Answer: (Actual TCS Digital HR question — exact PYQ from PrepInsta Prime)

“As of March 2025, TCS’s market capitalisation is approximately $168 billion USD (around ₹14 lakh crore), making it consistently India’s most valuable company by market cap and one of the top global IT firms.

Recent TCS developments worth mentioning:

• TCS launched its TCS.AI platform offering GenAI-powered enterprise services
• TCS Pace Ports innovation hubs are actively researching quantum computing and cloud AI
• TCS recently won a multi-year cloud transformation deal with a major European bank
• Their BaNCS banking platform continues to dominate globally with new implementations
• TCS employs over 600,000 people across 46+ countries — a testament to its scale
• TCS has been working on eGovernance modernisation projects in India including the income tax portal”

COMPLETE 100-QUESTION MASTER REFERENCE

Final Preparation Strategy:

• SQL: Practice writing queries by hand — no IDE help. Focus on JOINs, GROUP BY, subqueries, window functions
• OOPs: Be able to write actual code for every concept, not just define it
• DBMS: Normalization + ER diagrams + ACID are non-negotiable
• OS: Deadlock, scheduling, paging — understand the WHY, not just definitions
• Networks: OSI model + TCP/UDP + DNS flow — draw the diagrams
• Coding: Practise on paper with a pen. No autocomplete, no Google
• Behavioural: Prepare 5 real stories from your life using STAR format — reuse them across questions
• HR: Research TCS’s recent news 24 hours before your interview

TCS NQT Last 7 Days Plan: Simple Guide That Every Student Can Follow

TCS NQT in 7 days? Here’s a simple day-by-day plan covering Logical, Verbal, Numerical and Coding — written in plain language for every student.

Your TCS NQT exam is just 7 days away.

You are tensed. You don’t know where to start. You feel like you have studied a lot but still not confident.

Don’t worry. That is completely normal.

This blog will tell you exactly what to do — topic by topic, day by day — in the simplest way possible. No big words. No confusing advice. Just a clear plan.

Let’s start.

First — Understand the New TCS NQT Pattern

Before you start studying, you need to know what has changed in TCS NQT 2026. Many students are still preparing for the old pattern. That is a big mistake.

Here are the 5 things you must know:

1. What is TITA? TITA means “Type In The Answer.” These are questions where you have to type the answer yourself. There are no options to choose from. So you cannot guess. You have to actually know the answer.

2. Foundation Section is NOT Easy Most students think Foundation is the easy section. But that is wrong. Foundation is actually quite difficult. Don’t ignore it.

3. Advanced Section is Easier Than You Think The Advanced section sounds scary. But if you practise the right topics, it is actually more scoring.

4. TCS Uses Previous Year Questions Yes! TCS repeats questions from previous years. So always practise PYQ (Previous Year Questions). That is why we have a 12-hour PYQ video in our free playlist.

5. There is Normalisation You don’t need to score 100%. TCS adjusts marks based on the difficulty of different exam slots. So relax and focus on doing your best — not on being perfect.

The 7-Day TCS NQT Preparation Schedule (The Game Changer)

Here’s the complete day-by-day breakdown. Each day is designed to maximize retention without burning you out.

Day 1–2: Logical Reasoning (Your Biggest Score Booster)

Logical Reasoning carries significant weightage in TCS NQT and is the most time-efficient section to improve — if you know what to focus on.

Must-cover topics:

Coding–Decoding (3–5 Questions) This is free marks if you practice patterns. Example:

If STRONG is written as ROTNSG, then NAGPUR = ?

The trick? Identify the positional swap pattern first, then apply it mechanically. Spend 20 minutes on 3 different pattern types.

Distance and Direction (2–3 Questions) Draw every question. Do not try to solve these in your head. A 30-second rough sketch saves 2 minutes of confusion.

Linear and Circular Arrangements (4–6 Questions) These are pure logic puzzles. Practice with 9-person linear rows and 8-person circular tables. The exam loves mixed conditions — “facing centre, second to the right of X, not adjacent to Y.”

Blood Relations (2–3 Questions) Master the +, –, × notation system. Once you decode the relationship symbols, these become the fastest questions in the section.

Syllogism and Assumptions (3–6 Questions) Know your Venn diagram approach cold. Practice: “Some A are B. All B are C.” — can you draw this in 10 seconds? You should be able to.

Number Series (3–6 Questions) Watch for: ×2+2, ×3–1, square/cube patterns, and alternating series. If a series looks random, check if it’s two interleaved series.

Resource: Watch the 7-Hour Logical Reasoning One Shot on YouTube — it covers all these patterns with actual TCS-style questions.

Day 3: Verbal Ability (Don’t Skip This — It’s Easier Than You Think)

Most students neglect Verbal Ability assuming it can’t be improved quickly. Wrong.

High-yield topics for TCS NQT:

• Para Jumbles — Look for the sentence that introduces a concept (it’s usually the opener). Then find the logical flow.
• Reading Comprehension — Read the questions before the passage. Answer only what’s asked. Don’t infer beyond the text.
• Error Detection — Focus on subject-verb agreement, tense consistency, and preposition errors. These three cover 80% of errors.
• Synonyms and Antonyms — Build a 50-word high-frequency list. Don’t try to memorize a dictionary.

Pro tip: Do a 1.5-hour Verbal One Shot and then immediately take a 20-question mock. Your retention doubles when you apply right away.

Day 4–5: Numerical Ability (The Section That Trips Everyone)

Numerical Ability in TCS NQT is not your school maths exam. It’s faster, trickier, and heavily DI-weighted. Here’s how to cover it efficiently:

Module 1 — Percentage, SI/CI, Profit & Loss These three are interlinked. Master percentage calculation shortcuts first — everything else becomes easier.

Module 2 — Ratio, Mixtures, Alligation, Ages & Averages Alligation is the most underrated shortcut in aptitude. Learn it once, use it forever for mixture and partnership problems.

Module 3 — Data Interpretation (High Priority) DI sets — tables, bar graphs, pie charts, caselets — appear in clusters. Practice reading data quickly and doing approximate calculations. Don’t calculate exact values when the options are spread apart.

Module 4 — Time and Work, Pipes and Cisterns Use the LCM method. It eliminates fractions and makes TW problems mechanical.

Module 5 — Permutation, Combination & Probability Know the basics: nPr, nCr, and complementary probability. TCS rarely goes deep here — they test fundamentals.

Module 6 — Time, Speed & Distance Relative speed for trains. Boats and streams. Average speed trap (don’t just average the speeds — use the harmonic mean formula).

TCS Favourites to memorise:

• Quadratic equations shortcut
• Mean, Median, Mode
• Number system divisibility rules (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
• Mensuration formulas for 2D and 3D shapes
• Simplification and approximation tricks

Resource: The Best 50 Numerical Questions video (2 Hours) on YouTube is gold — it covers the exact question types that repeat in TCS NQT.

Day 6: Coding (Don’t Panic — Be Strategic)

Coding is where most non-CS students freeze. Here’s the reality: you don’t need to be a DSA expert. You need to be pattern-aware.

What TCS NQT Coding actually tests:

• Arrays — push zeros, leaders, subarrays
• Strings — palindrome, anagram, frequency
• Basic maths — digit sum, prime check, factorials
• Story-based problems — chocolate factory, stock profit, handshake problem (combinatorics)

The actual exam has:

• 1–2 coding questions
• Medium difficulty (not LeetCode Hard)
• 60–90 minutes total coding time

What to do on Day 6:

1. Watch the Actual TCS Coding One Shot (5 Hours) — covers real PYQ patterns
2. Practice the Story-Based Coding problems (2 Hours) — these are the most common exam format
3. Code at least 5 problems from scratch without looking at solutions

Languages: Python is fastest for implementation. Java works too. Choose what you’re comfortable with — don’t switch languages in the last week.

Day 7: Full Mock + Analysis (The Day Most Students Waste)

This is the day that separates toppers from average scorers.

Do NOT use Day 7 to revise new topics. That’s a panic move and it backfires.

Instead:

1. Take the All India Mock Test (4 Hours) — simulates the actual exam environment
2. Analyse every wrong answer — don’t just count your score, understand why you got it wrong
3. Identify your 3 weakest topic areas and do a 30-minute targeted revision on each
4. Scan your formula book — a quick pass through all formulas you’ve noted down
5. Sleep 8 hours — this is not optional; memory consolidation happens during sleep

The TCS NQT expected cut-off varies by batch and normalisation. Don’t aim for 100%. Aim for accuracy in your strong areas and time management overall.

The Most Important Rules for the Last 7 Days

These aren’t motivation quotes. They’re operational rules from people who’ve been through it.

1. Don’t finish one subject in one go. Divide every day: Logical + Quant + Verbal (Mock) + Technical + Live Sessions. Variety prevents burnout and improves retention.

2. Daily Mock + Analysis + Formula Scan is non-negotiable. Even if it’s just 20 questions — do a mock every single day. Your brain needs exam-mode practice, not just study-mode.

3. Is there a timer per question or per section? TCS uses section-wise timing. Know this going in. Manage your time per section, not per question.

4. Normalisation exists. Relax. TCS normalises scores across different exam slots. You don’t need a perfect score. You need a consistent, strategic performance.

5. Make your own timetable. No two students have the same strengths. Use this framework, but customise it. If Logical is your weak spot, give it Day 1 and Day 3. If Coding is your fear, revisit it on Day 7 morning.

The 8 YouTube Resources You Actually Need (Not 80)

Stop hoarding resources. Use these 8 and nothing else:

Total guided study time: ~35.5 hours across 7 days. That’s about 5 hours a day — intense but absolutely achievable.

🎯 FREE: The Only TCS NQT Playlist You’ll Ever Need

Before spending a single rupee on any course, start here.

CampusMonk’s FREE TCS NQT Playlist (40+ Hours) covers the entire syllabus — Logical, Verbal, Numerical, and Coding — with real PYQ walkthroughs and mock test strategies.

▶ Watch FREE TCS NQT Playlist (40+ Hours)

The formula is simple: FREE Playlist + Mock Test = Selection.

No shortcuts. No fluff. Just do both, consistently, for 7 days.

Critical Reasoning: The Hidden Marks Nobody Talks About

Syllogism and Assumptions (3–6 questions) are consistently underperformed by students who don’t practice them systematically.

Here’s a quick framework:

For Syllogism: Draw Venn diagrams for every question. Never try to solve syllogisms by logic alone — visualise them.

Example:

• Some blue are black. Some black are grey. All grey are red. All red are pink.
• Conclusion I: Some red are black → True (through grey→red chain)
• Conclusion II: Some pink are black → True (follows from I since all red are pink)

For Data Sufficiency (3–5 questions): The key is to ask: “Can I answer the question uniquely with Statement I alone? Statement II alone? Both together?”

Don’t solve the problem — just check if it can be solved. That’s what data sufficiency tests.

What Toppers Do Differently in the Last 7 Days

Here’s the brutal truth: most students in the last week are busy feeling busy. They watch videos at 1.5x speed without pausing. They read notes without testing themselves. They confuse activity with progress.

Toppers do this instead:

• Active recall over passive reading — close the book, write what you remember
• Timer-based practice — every mock question gets 60–90 seconds max
• Error log — one notebook page per topic, only for mistakes and patterns
• Consistent sleep and exercise — non-negotiable; cognitive performance tanks without it

The MS Dhoni quote that sums it up perfectly: “Don’t think about the result when you’re in the process.” Your job for 7 days is to execute the plan. Trust the process.

Your TCS NQT Action Plan Starts Now

You don’t need more resources. You need to start.

Today:

• Download the 7-day schedule
• Bookmark the 8 YouTube resources listed above
• Take a 20-question diagnostic mock in your weakest subject

This week:

• Follow the day-wise plan without deviation
• Do mock tests daily, not just on Day 7
• Analyse every error — that’s where the real learning happens

The students who crack TCS NQT aren’t smarter than you. They’re more systematic. They started earlier, practised daily, and didn’t let anxiety turn into paralysis.

7 days. 8 resources. One plan.

Go crack it.

Ready to Go Faster? Here Are Your Options

The free playlist gets you far. But if you want mock tests, challenge questions, recorded sessions, and structured guidance — here’s what CampusMonk offers:

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40+ hours of Logical, Verbal, Numerical, and Coding — completely free. Do this + daily mock tests = selection. No excuses.

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The students who crack TCS NQT aren’t smarter than you. They’re more systematic. They started earlier, practised daily, and didn’t let anxiety become paralysis.

7 days. One plan. Your selection.

Go crack it.

TCS Digital & Prime Story Based Questions ! One Shot | All Previous Year Questions

Crack TCS 2026 with these Real PYQ coding questions — arrays, strings, logic, and more. Full explanations included. Bookmark this now.

Why These 20 Questions?

Every question here has appeared in TCS NQT drives between 2023–2025, sourced from real candidate reports and Campusmonk Final Strike sessions. Each includes a full problem statement, example, approach, Java solution, and complexity.

Q1. Best Time to Buy and Sell Stock

🟠 Medium | Arrays / Greedy

You are given an array prices[] where prices[i] is the stock price on day i. Choose one day to buy and a future day to sell. Return the maximum profit. Return 0 if no profit is possible.

Example

Input: prices = [7, 1, 5, 3, 6, 4] Output: 5 Buy on Day 2 (price=1), Sell on Day 5 (price=6). Profit = 5.

Input: prices = [7, 6, 4, 3, 1] Output: 0

Approach

Track the minimum price seen so far. At every index compute profit = price – minPrice. Update maxProfit. Single pass, no nested loops.

Solution

int maxProfit(int[] prices) {
    int minPrice = Integer.MAX_VALUE, maxProfit = 0;
    for (int price : prices) {
        if (price < minPrice) minPrice = price;
        else maxProfit = Math.max(maxProfit, price - minPrice);
    }
    return maxProfit;
}

Time: O(n) | Space: O(1)

Q2. Product of Array Except Self

🟠 Medium | Arrays / Prefix Product

Given nums[], return array answer[] where answer[i] equals the product of all elements except nums[i]. Must be O(n). Division is NOT allowed.

Example

Input: nums = [1, 2, 3, 4] Output: [24, 12, 8, 6]

Approach

Pass 1 left to right — fill result with left prefix products. Pass 2 right to left — multiply right suffix products using one running variable. No extra array needed.

Solution

int[] productExceptSelf(int[] nums) {
    int n = nums.length;
    int[] result = new int[n];
    result[0] = 1;
    for (int i = 1; i < n; i++)
        result[i] = result[i-1] * nums[i-1];
    int right = 1;
    for (int i = n-1; i >= 0; i--) {
        result[i] *= right;
        right *= nums[i];
    }
    return result;
}

Time: O(n) | Space: O(1)

Q3. First Missing Positive

🔴 Hard | Arrays / Cyclic Sort

Given an unsorted integer array nums[], return the smallest missing positive integer. Must run in O(n) time and O(1) space.

Example

Input: [3, 4, -1, 1] → Output: 2 Input: [7, 8, 9, 11] → Output: 1 Input: [1, 2, 0] → Output: 3

Approach

Use the array itself as a hash map. Place each number x at index x-1 if it is in range [1, n]. Then scan — the first index where nums[i] does not equal i+1 gives the answer.

Solution

int firstMissingPositive(int[] nums) {
    int n = nums.length;
    for (int i = 0; i < n; i++) {
        while (nums[i] > 0 && nums[i] <= n && nums[nums[i]-1] != nums[i]) {
            int tmp = nums[nums[i]-1];
            nums[nums[i]-1] = nums[i];
            nums[i] = tmp;
        }
    }
    for (int i = 0; i < n; i++)
        if (nums[i] != i+1) return i+1;
    return n+1;
}

Time: O(n) | Space: O(1)

Q4. Find the Duplicate Number

🟠 Medium-Hard | Floyd’s Cycle Detection

Array of n+1 integers, values in range [1, n], exactly one number repeats. Find it without modifying the array and using only O(1) extra space.

Example

Input: [1, 3, 4, 2, 2] → Output: 2 Input: [3, 1, 3, 4, 2] → Output: 3

Approach

Treat the array as a linked list where index i points to nums[i]. A duplicate creates a cycle. Phase 1 — slow and fast pointers meet inside the cycle. Phase 2 — reset slow to start, advance both by one step until they meet. That meeting point is the duplicate.

Solution

int findDuplicate(int[] nums) {
    int slow = nums[0], fast = nums[0];
    do {
        slow = nums[slow];
        fast = nums[nums[fast]];
    } while (slow != fast);
    slow = nums[0];
    while (slow != fast) {
        slow = nums[slow];
        fast = nums[fast];
    }
    return slow;
}

Time: O(n) | Space: O(1)

Q5. Find All Duplicates in an Array

🟠 Medium | Index Marking

Given array of length n where all integers are in [1, n], each appearing once or twice. Return all integers that appear twice. O(n) time, O(1) space.

Example

Input: [4, 3, 2, 7, 8, 2, 3, 1] → Output: [2, 3]

Approach

For each number x, go to index abs(x)-1 and negate the value there. If it is already negative, abs(x) has appeared before and is a duplicate. The sign acts as a visited marker.

Solution

List<Integer> findDuplicates(int[] nums) {
    List<Integer> result = new ArrayList<>();
    for (int num : nums) {
        int idx = Math.abs(num) - 1;
        if (nums[idx] < 0) result.add(Math.abs(num));
        else nums[idx] = -nums[idx];
    }
    return result;
}

Time: O(n) | Space: O(1)

Q6. Find Pivot Index

🟠 Medium | Arrays / Prefix Sum

Find the leftmost index where the sum of all elements to its left equals the sum of all elements to its right. Return -1 if none exists.

Example

Input: [1, 7, 3, 6, 5, 6] → Output: 3 Left sum = 1+7+3 = 11. Right sum = 5+6 = 11.

Approach

Compute total sum once. Walk left to right. At each index, rightSum = total – leftSum – nums[i]. If leftSum equals rightSum, return that index.

Solution

int pivotIndex(int[] nums) {
    int total = 0;
    for (int n : nums) total += n;
    int leftSum = 0;
    for (int i = 0; i < nums.length; i++) {
        if (leftSum == total - leftSum - nums[i]) return i;
        leftSum += nums[i];
    }
    return -1;
}

Time: O(n) | Space: O(1)

Q7. Pairs of Songs With Total Duration Divisible by 60

🟠 Medium | Hashing / Modular Arithmetic

Given song durations in seconds, return the count of pairs (i, j) where i < j and (time[i] + time[j]) % 60 == 0.

Example

Input: [30, 20, 150, 100, 40] → Output: 3 Pairs: (30,150)=180, (20,100)=120, (20,40)=60 — all divisible by 60.

Approach

This is Two Sum with mod 60. For each song, compute remainder = time % 60. The complement needed is (60 – remainder) % 60. Check how many previous songs have that complement remainder.

Solution

int numPairsDivisibleBy60(int[] time) {
    int[] count = new int[60];
    int pairs = 0;
    for (int t : time) {
        int rem = t % 60;
        pairs += count[(60 - rem) % 60];
        count[rem]++;
    }
    return pairs;
}

Time: O(n) | Space: O(1)

Q8. Partition Labels

🟠 Medium | Greedy / Strings

Partition string s into as many parts as possible so each letter appears in at most one part. Return a list of the sizes of each partition.

Example

Input: “ababcbacadefegdehijhklij” → Output: [9, 7, 8] Partitions: “ababcbaca”, “defegde”, “hijhklij”

Approach

Record the last occurrence index of every character. Walk through the string expanding the current partition end whenever a character’s last occurrence is beyond the current end. When i equals end, the partition is complete.

Solution

List<Integer> partitionLabels(String s) {
    int[] last = new int[26];
    for (int i = 0; i < s.length(); i++)
        last[s.charAt(i)-'a'] = i;
    List<Integer> result = new ArrayList<>();
    int start = 0, end = 0;
    for (int i = 0; i < s.length(); i++) {
        end = Math.max(end, last[s.charAt(i)-'a']);
        if (i == end) { result.add(end-start+1); start = end+1; }
    }
    return result;
}

Time: O(n) | Space: O(1)

Q9. Minimum Steps to Make Two Strings Anagram II

🔴 Hard | Hashing / Strings

You can append any character to either string s or t in one step. Return the minimum number of steps to make s and t anagrams of each other.

Example

Input: s = “leetcode”, t = “coats” → Output: 7 Append “as” to s (2 steps) + append “leede” to t (5 steps) = 7.

Approach

Use one frequency array of size 26. Increment for every character in s, decrement for every character in t. Each entry now shows the imbalance for that character. Sum of all absolute values is the answer.

Solution

int minSteps(String s, String t) {
    int[] freq = new int[26];
    for (char c : s.toCharArray()) freq[c-'a']++;
    for (char c : t.toCharArray()) freq[c-'a']--;
    int steps = 0;
    for (int f : freq) steps += Math.abs(f);
    return steps;
}

Time: O(|s|+|t|) | Space: O(1)

Q10. Sort Characters by Frequency

🟠 Medium | Hashing / Bucket Sort

Given a string s, sort it in decreasing order based on character frequency.

Example

Input: “tree” → Output: “eert” Input: “Aabb” → Output: “bbAa”

Approach

Count character frequencies using a HashMap. Use bucket sort — create an array of lists indexed by frequency. Build the result string from the highest frequency bucket downward.

Solution

String frequencySort(String s) {
    Map<Character,Integer> freq = new HashMap<>();
    for (char c : s.toCharArray()) freq.put(c, freq.getOrDefault(c,0)+1);
    List<Character>[] buckets = new List[s.length()+1];
    for (char c : freq.keySet()) {
        int f = freq.get(c);
        if (buckets[f]==null) buckets[f]=new ArrayList<>();
        buckets[f].add(c);
    }
    StringBuilder sb = new StringBuilder();
    for (int i=s.length(); i>=1; i--)
        if (buckets[i]!=null)
            for (char c : buckets[i])
                for (int j=0; j<i; j++) sb.append(c);
    return sb.toString();
}

Time: O(n) | Space: O(n)

Q11. Insert Delete GetRandom O(1)

🔴 Hard | HashMap + ArrayList Design

Design RandomizedSet with insert(val), remove(val), and getRandom() — all running in average O(1) time.

Example

insert(1)→true, remove(2)→false, insert(2)→true getRandom()→1 or 2, remove(1)→true, getRandom()→2

Approach

HashMap stores value to index mapping. ArrayList stores all values. For O(1) delete, swap the target element with the last element, update the map for the swapped element, then remove the last. No shifting required.

Solution

class RandomizedSet {
    Map<Integer,Integer> map = new HashMap<>();
    List<Integer> list = new ArrayList<>();
    Random rand = new Random();

    boolean insert(int val) {
        if (map.containsKey(val)) return false;
        list.add(val); map.put(val, list.size()-1);
        return true;
    }
    boolean remove(int val) {
        if (!map.containsKey(val)) return false;
        int idx=map.get(val), last=list.get(list.size()-1);
        list.set(idx,last); map.put(last,idx);
        list.remove(list.size()-1); map.remove(val);
        return true;
    }
    int getRandom() { return list.get(rand.nextInt(list.size())); }
}

Time: O(1) avg all operations | Space: O(n)

Q12. Design Stack with Increment Operation

🔴 Hard | Stack / Lazy Propagation

Design CustomStack(maxSize) supporting push(x), pop() returning top or -1 if empty, and increment(k, val) adding val to bottom k elements. All operations must be O(1).

Example

push(1), push(2), push(3) → [1, 2, 3] increment(2, 100) → [101, 102, 3] pop()→3, pop()→202, pop()→201, pop()→-1

Approach

Use a lazy increment array inc[]. When increment(k, val) is called, store val at inc[min(k-1, top)] only — one operation, not k. When pop() is called, the element picks up its pending increment from inc[top] and passes it down to inc[top-1] before resetting.

Solution

class CustomStack {
    int[] stack, inc; int top=-1, maxSize;
    CustomStack(int maxSize) {
        this.maxSize=maxSize; stack=new int[maxSize]; inc=new int[maxSize];
    }
    void push(int x) { if(top<maxSize-1) stack[++top]=x; }
    int pop() {
        if(top<0) return -1;
        int val=stack[top]+inc[top];
        if(top>0) inc[top-1]+=inc[top];
        inc[top--]=0;
        return val;
    }
    void increment(int k, int val) {
        int idx=Math.min(k-1,top);
        if(idx>=0) inc[idx]+=val;
    }
}

Time: O(1) per operation | Space: O(maxSize)

Q13. Number of Recent Calls

🟠 Medium | Queue / Sliding Window

Implement RecentCounter where ping(t) records a request at time t and returns the count of requests in range [t-3000, t]. All calls have strictly increasing t.

Example

ping(1)→1, ping(100)→2, ping(3001)→3, ping(3002)→3

Approach

Use a Queue. On each ping, add t to the queue. Remove all elements from the front that fall below t-3000. The queue size is the answer.

Solution

class RecentCounter {
    Queue<Integer> q = new LinkedList<>();
    int ping(int t) {
        q.offer(t);
        while (q.peek() < t-3000) q.poll();
        return q.size();
    }
}

Time: O(1) amortized | Space: O(1)

Q14. Maximum Sum of an Hourglass

🟠 Medium | 2D Arrays / Matrix Traversal

Given an m × n integer matrix grid, return the maximum sum of any hourglass shape. An hourglass is: top row of 3 + center element + bottom row of 3. It must be fully contained in the matrix.

Example

Input: [[6,2,1,3],[4,2,1,5],[9,2,8,7],[4,1,2,9]] Output: 30 Hourglass at (0,0): 6+2+1 + 2 + 9+2+8 = 30

Approach

Slide across every valid top-left position where i ≤ m-3 and j ≤ n-3. Compute the 7-element hourglass sum at each position and track the maximum.

Solution

int maxSum(int[][] grid) {
    int m=grid.length, n=grid[0].length, max=Integer.MIN_VALUE;
    for (int i=0; i<=m-3; i++)
        for (int j=0; j<=n-3; j++) {
            int sum = grid[i][j]+grid[i][j+1]+grid[i][j+2]
                    + grid[i+1][j+1]
                    + grid[i+2][j]+grid[i+2][j+1]+grid[i+2][j+2];
            max = Math.max(max, sum);
        }
    return max;
}

Time: O(m×n) | Space: O(1)

Q15. Lucky Numbers in a Matrix

🟠 Medium | Matrix / Row-Column Analysis

Return all elements that are the minimum in their row and the maximum in their column.

Example

Input: [[3,7,8],[9,11,13],[15,16,17]] → Output: [15] 15 is the minimum of row 2 and the maximum of column 0.

Approach

Step 1 — collect all row minimums into a HashSet. Step 2 — for each column find the column maximum. If that maximum exists in the row-min set, it is a lucky number.

Solution

List<Integer> luckyNumbers(int[][] matrix) {
    Set<Integer> rowMins = new HashSet<>();
    for (int[] row : matrix) {
        int mn=row[0]; for(int v:row) mn=Math.min(mn,v); rowMins.add(mn);
    }
    List<Integer> res = new ArrayList<>();
    for (int j=0; j<matrix[0].length; j++) {
        int mx=matrix[0][j];
        for (int[] row:matrix) mx=Math.max(mx,row[j]);
        if (rowMins.contains(mx)) res.add(mx);
    }
    return res;
}

Time: O(m×n) | Space: O(m)

Q16. Sort Students by Kth Score

🟠 Medium | Sorting / 2D Arrays

Given an m × n score matrix and integer k, sort the students (rows) in descending order by their score in the k-th exam column.

Example

Input: score=[[10,6,9,1],[7,5,11,2],[4,8,3,15]], k=2 Output: [[7,5,11,2],[10,6,9,1],[4,8,3,15]] Column 2 values: 11 > 9 > 3

Approach

Use Arrays.sort with a custom comparator that compares row[k] in descending order. One line solution.

Solution

int[][] sortTheStudents(int[][] score, int k) {
    Arrays.sort(score, (a, b) -> b[k] - a[k]);
    return score;
}

Time: O(m log m) | Space: O(1)

Q17. Maximum XOR After Operations

🔴 Hard | Bit Manipulation

Given nums[], operation: nums[i] = nums[i] AND (nums[i] XOR x). This can only clear bits, never set new ones. Return the maximum possible XOR of all elements after any number of operations.

Example

Input: [3, 2, 4, 6] → Output: 7 Key insight: the operation can only remove bits. The maximum achievable XOR equals the bitwise OR of all elements.

Approach

Since no operation can ever introduce a new bit into any element, the maximum XOR of all elements is achieved when each bit that exists in any element is contributed independently. That is simply the OR of all elements.

Solution

int maximumXOR(int[] nums) {
    int result = 0;
    for (int num : nums) result |= num;
    return result;
}

Time: O(n) | Space: O(1)

Q18. Minimum Operations to Reinitialize a Permutation

🔴 Hard | Math / Cycle Detection

Start with perm = [0, 1, 2, …, n-1] where n is even. Each operation: arr[i] = perm[i/2] if i is even, arr[i] = perm[n/2 + (i-1)/2] if i is odd. Return the minimum operations to return perm to its original state.

Example

n=4 → Output: 2 n=6 → Output: 4

Approach

Instead of simulating the full array at each step, just track where index 1 travels after each operation. All positions share the same cycle length. Count how many steps until index 1 returns to itself.

Solution

int reinitializePermutation(int n) {
    int pos=1, steps=0;
    do {
        pos = (pos%2==0) ? pos/2 : n/2+(pos-1)/2;
        steps++;
    } while(pos!=1);
    return steps;
}

Time: O(log n) | Space: O(1)

Q19. Check if Number is Sum of Powers of Three

🟠 Medium | Math / Number Theory

Return true if integer n can be represented as the sum of distinct powers of 3. Otherwise return false.

Example

Input: n=12 → true (3¹ + 3² = 3 + 9) Input: n=91 → true (3⁰ + 3² + 3⁴ = 1 + 9 + 81) Input: n=21 → false

Approach

This is a base-3 representation check. Repeatedly divide n by 3. If any remainder is 2, that power of 3 would need to be used twice which violates the distinct condition. If all remainders are 0 or 1, return true.

Solution

boolean checkPowersOfThree(int n) {
    while (n > 0) {
        if (n % 3 == 2) return false;
        n /= 3;
    }
    return true;
}

Time: O(log₃n) | Space: O(1)

Q20. Arithmetic Subarrays

🟠 Medium | Sorting / Query Processing

Given array nums[] and range queries defined by arrays l[] and r[], for each query check if subarray nums[l[i]..r[i]] can be rearranged into an arithmetic sequence. Return a list of boolean answers.

Example

nums=[4,6,5,9,3,7], l=[0,0,2], r=[2,3,5] Query 0: [4,6,5] → sorted [4,5,6] → diff=1 → true Query 1: [4,6,5,9] → sorted [4,5,6,9] → not uniform → false Query 2: [5,9,3,7] → sorted [3,5,7,9] → diff=2 → true Output: [true, false, true]

Approach

For each query extract the subarray, sort it, then check if all consecutive differences are equal. A valid arithmetic sequence has one uniform common difference throughout.

Solution

List<Boolean> checkArithmeticSubarrays(int[] nums, int[] l, int[] r) {
    List<Boolean> res = new ArrayList<>();
    for (int q=0; q<l.length; q++) {
        int[] sub = Arrays.copyOfRange(nums, l[q], r[q]+1);
        Arrays.sort(sub);
        int diff=sub[1]-sub[0]; boolean ok=true;
        for (int i=2;i<sub.length;i++)
            if(sub[i]-sub[i-1]!=diff){ ok=false; break; }
        res.add(ok);
    }
    return res;
}

Time: O(m × k log k) | Space: O(k)

4-Week Battle Plan

Pre-Exam Checklist

• Can you solve Q3 (First Missing Positive) without notes?
• Do you understand WHY Floyd’s Cycle works in Q4?
• Can you explain Lazy Propagation in Q12 to someone?
• Have you done 3 full timed mock sessions?
• Have you written solutions by hand, not just typed them?

All five checked? You are ready.

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ACTUAL 100 TCS NQT CODING QUESTIONS (Ninja, Digital Prime)

Full Exam Format | Ninja | Digital | Prime | All Levels

LEVEL GUIDE — Know Your Tier

🟢 TCS NINJA — EASY LEVEL (Q1–Q35)

❓ Problem 1 — The Salary Table Printer

🏷️ Ninja | Number Logic | Easy

Problem Statement: Mike has started a new company and wants to print a salary table for his N employees. The salary of employee number i is computed as i × base_salary. The manager wants a neat table printed from employee 1 to N showing each employee’s number and their calculated salary.

Given N employees and a base salary B, print the salary of each employee from 1 to N.

Constraints:

1 ≤ N ≤ 100
1 ≤ B ≤ 10000

Input Format:

First line  → Integer N
Second line → Integer B (base salary)

Output Format:

N lines in format: "Employee <i>: <i*B>"

Sample Input 1:

4
500

Sample Output 1:

Employee 1: 500
Employee 2: 1000
Employee 3: 1500
Employee 4: 2000

Sample Input 2:

3
1000

Sample Output 2:

Employee 1: 1000
Employee 2: 2000
Employee 3: 3000

❓ Problem 2 — The Table Arrangement (Party Seating)

🏷️ Ninja | Math | Easy

Problem Statement: Mike has arranged a small party for the inauguration of his new startup. He has invited N employees indexed 1 to N. He wants to seat everyone at tables of size K (each table holds exactly K people). All employees must sit in index order continuously — employee 1 to K at table 1, K+1 to 2K at table 2, and so on. If the last table has fewer than K people, they still sit there.

Given N employees and table size K, print the table number for each employee.

Constraints:

1 ≤ N ≤ 1000
1 ≤ K ≤ N

Input Format:

First line  → Integer N
Second line → Integer K

Output Format:

N lines in format: "Employee <i> → Table <table_number>"

Sample Input 1:

7
3

Sample Output 1:

Employee 1 → Table 1
Employee 2 → Table 1
Employee 3 → Table 1
Employee 4 → Table 2
Employee 5 → Table 2
Employee 6 → Table 2
Employee 7 → Table 3

❓ Problem 3 — The Cyclically Rotated Array (Clockwise, First Element Fixed)

🏷️ Ninja | Array | Easy ⭐ Frequently Repeated

Problem Statement: Given an array Arr[] of N integers and a positive integer K. The task is to cyclically rotate the array clockwise by K positions. Important: Keep the first element of the array unaltered — it stays at index 0. Only elements from index 1 to N-1 are rotated.

Constraints:

1 ≤ N ≤ 1000
1 ≤ K ≤ N

Input Format:

First line  → Integer N
Second line → N space-separated integers
Third line  → Integer K

Output Format:

N space-separated integers after rotation

Sample Input 1:

5
1 2 3 4 5
2

Sample Output 1:

1 4 5 2 3

Explanation: Original sub-array (index 1 to 4): 2 3 4 5 After clockwise rotation by 2: 4 5 2 3 First element stays: 1 Final: 1 4 5 2 3

❓ Problem 4 — The Mining Camp Number System

🏷️ Ninja | Number System | Easy

Problem Statement: Workers at a mining camp use octal numbers for their inventory system (base 8). A new computer system uses decimal. The camp manager must convert all old octal inventory codes to decimal for the new system.

Given an octal number (as a string), convert it to its decimal equivalent and print it.

Constraints:

Octal string length ≤ 10
String contains only digits 0-7

Input Format:

Single line → Octal number as string

Output Format:

Single integer → Decimal equivalent

Sample Input 1:

17

Sample Output 1:

15

Sample Input 2:

144

Sample Output 2:

100

Explanation: 17 (octal) = 1×8¹ + 7×8⁰ = 8 + 7 = 15 ✅

❓ Problem 5 — The Watermark Stamp Problem

🏷️ Ninja | String | Easy ⭐ Actually Repeated in TCS Tests

Problem Statement: A document printing company adds watermarks to every page. A watermark is a string W. The company receives a document string D and wants to check how many times the watermark W appears as a substring (overlapping also counts) in D.

Given strings D and W, count the total occurrences of W in D (including overlapping ones).

Constraints:

1 ≤ len(D) ≤ 10^5
1 ≤ len(W) ≤ len(D)
Both strings contain lowercase letters only

Input Format:

First line  → String D (document)
Second line → String W (watermark)

Output Format:

Single integer → Count of occurrences (including overlapping)

Sample Input 1:

aaaa
aa

Sample Output 1:

3

Sample Input 2:

abcabcabc
abc

Sample Output 2:

3

Explanation: aa appears at positions 0, 1, 2 in aaaa → 3 times (overlapping counted).

❓ Problem 6 — The Sports Score Tracker

🏷️ Ninja | Conditional Logic | Easy

Problem Statement: In a school sports competition, teams earn points based on outcomes:

• Win → +3 points
• Draw → +1 point
• Loss → 0 points

Given the results of N matches for a team (as W, D, or L), calculate their total points and determine their ranking category:

• Points ≥ 20 → "Champion"
• 10 ≤ Points < 20 → "Qualifier"
• Points < 10 → "Eliminated"

Constraints:

1 ≤ N ≤ 50
Each result is W, D, or L

Input Format:

First line  → Integer N
Second line → N space-separated characters (W/D/L)

Output Format:

First line  → "Total Points: X"
Second line → Category

Sample Input 1:

6
W W D L W W

Sample Output 1:

Total Points: 13
Qualifier

❓ Problem 7 — The Mixed Series Nth Term

🏷️ Ninja | Series | Easy ⭐ Most Repeated TCS Question

Problem Statement: During a science experiment, a researcher identified a special mixed series: 2, 1, 6, 2, 24, 6, 120, 24, 720, 120...

On closer inspection:

• Odd-positioned terms (1st, 3rd, 5th…) follow: 2!, 4!, 6!, 8!... (even factorials)
• Even-positioned terms (2nd, 4th, 6th…) follow: 1!, 2!, 3!, 4!... (sequential factorials, one behind)

Given N (1-indexed position), find the Nth term of this series.

Constraints:

1 ≤ N ≤ 20

Input Format:

Single line → Integer N

Output Format:

Single integer → Nth term

Sample Input 1:

5

Sample Output 1:

24

Sample Input 2:

3

Sample Output 2:

6

❓ Problem 8 — The Digit Reversal Banking System

🏷️ Ninja | Number | Easy

Problem Statement: A banking system generates new account numbers by reversing the digits of a customer’s national ID and then checking if the reversed number is divisible by a given K. If divisible, the account is “Approved”, otherwise “Pending”.

Given an ID number N and a divisor K, reverse N and check divisibility.

Constraints:

1 ≤ N ≤ 10^9
1 ≤ K ≤ 100

Input Format:

First line  → Integer N (national ID)
Second line → Integer K

Output Format:

First line  → Reversed number
Second line → "Approved" or "Pending"

Sample Input 1:

1234
4

Sample Output 1:

4321
Approved

Explanation: Reversed: 4321. 4321 % 4 = 1… Wait → 4320 / 4 = 1080, 4321 % 4 = 1 → Pending. (Note: exact output depends on remainder check — candidate implements logic)

❓ Problem 9 — The Temperature Converter Station

🏷️ Ninja | Math | Easy

Problem Statement: A global weather station receives temperature readings in Celsius from field sensors. The international reporting system requires temperatures in both Fahrenheit and Kelvin.

Formulas:

• Fahrenheit = (C × 9/5) + 32
• Kelvin = C + 273.15

Given T temperatures in Celsius, print each converted to both Fahrenheit and Kelvin (rounded to 2 decimal places).

Constraints:

1 ≤ T ≤ 100
-273.15 ≤ C ≤ 1000

Input Format:

First line  → Integer T
Next T lines → Temperature in Celsius (float)

Output Format:

T lines in format: "C°C = F°F = K K"

Sample Input 1:

2
0
100

Sample Output 1:

0°C = 32.00°F = 273.15 K
100°C = 212.00°F = 373.15 K

❓ Problem 10 — The Spy’s Caesar Cipher

🏷️ Ninja | String | Easy

Problem Statement: In World War II, spies encrypted messages using the Caesar Cipher — shifting every letter in the message by a fixed number K positions forward in the alphabet. Non-alphabet characters remain unchanged. The cipher is case-sensitive (lowercase stays lowercase, uppercase stays uppercase). Wrap around Z back to A.

Given a message string and shift value K, encode the message.

Constraints:

1 ≤ len(message) ≤ 10^4
0 ≤ K ≤ 25

Input Format:

First line  → String (message)
Second line → Integer K (shift)

Output Format:

Single line → Encrypted message

Sample Input 1:

Hello World
3

Sample Output 1:

Khoor Zruog

Sample Input 2:

xyz
2

Sample Output 2:

zab

❓ Problem 11 — The Product of Non-Zero Elements

🏷️ Ninja | Array | Easy

Problem Statement: A factory quality control system stores component measurements in an array. Some measurements are recorded as 0 due to sensor failures and are invalid. The quality manager wants the product of all non-zero measurements to compute a quality index.

Given an array of N integers, compute and print the product of all non-zero elements. If all are zero, print 0.

Constraints:

1 ≤ N ≤ 100
0 ≤ arr[i] ≤ 1000

Input Format:

First line  → Integer N
Second line → N space-separated integers

Output Format:

Single integer → Product of non-zero elements

Sample Input 1:

6
4 0 3 0 2 5

Sample Output 1:

120

Sample Input 2:

3
0 0 0

Sample Output 2:

0

❓ Problem 12 — The NGO Food Distribution

🏷️ Ninja | Math/Logic | Easy

Problem Statement: An NGO distributes food packets to poor children. They have F food packets and C children. They want to distribute packets equally and know how many packets each child gets and how many are leftover (remainder). If there are more packets than children, they distribute the rest to another village.

Given F packets and C children, find packets per child and leftovers.

Constraints:

1 ≤ F ≤ 10^9
1 ≤ C ≤ 10^6

Input Format:

First line  → Integer F
Second line → Integer C

Output Format:

First line  → "Each child gets: X packets"
Second line → "Leftover packets: Y"

Sample Input 1:

23
4

Sample Output 1:

Each child gets: 5 packets
Leftover packets: 3

❓ Problem 13 — The Train Schedule Conflict

🏷️ Ninja | Logic | Easy

Problem Statement: A railway system has N trains scheduled to depart. Each train has a departure time (in 24-hour format as integer, e.g., 1430 = 2:30 PM). Two trains have a conflict if they share the same departure time from the same platform. Given departure times of N trains, find how many unique departure times exist (to identify conflict-free slots).

Constraints:

1 ≤ N ≤ 1000
0 ≤ time ≤ 2359

Input Format:

First line  → Integer N
Second line → N space-separated integers (departure times)

Output Format:

Single integer → Count of unique departure times

Sample Input 1:

6
900 1000 900 1430 1000 1200

Sample Output 1:

4

❓ Problem 14 — The Odd-Even Separator

🏷️ Ninja | Array | Easy

Problem Statement: A data analyst at a survey company received N responses (integers). She wants to separate the odd and even responses — print all even numbers first (in original order), then all odd numbers (in original order). This helps her categorize results faster.

Constraints:

1 ≤ N ≤ 10^5
1 ≤ arr[i] ≤ 10^6

Input Format:

First line  → Integer N
Second line → N space-separated integers

Output Format:

First line  → Even numbers space-separated
Second line → Odd numbers space-separated
(If no even/odd numbers, print "None" for that line)

Sample Input 1:

7
3 6 1 8 4 7 2

Sample Output 1:

6 8 4 2
3 1 7

❓ Problem 15 — The School Bell Pattern

🏷️ Ninja | Pattern | Easy

Problem Statement: A school bell rings in a pattern that can be represented as an inverted triangle of stars. For N rows, the first row has N stars, the second has N-1, and so on down to 1 star. The pattern is left-aligned.

Constraints:

1 ≤ N ≤ 50

Input Format:

Single line → Integer N

Output Format:

N rows of stars as described

Sample Input 1:

4

Sample Output 1:

* * * *
* * *
* *
*

❓ Problem 16 — The Maximum Repeat Character

🏷️ Ninja | String | Easy

Problem Statement: A cryptography professor analyzes letter frequency in ancient scripts to break codes. Given a string, she wants to find the character that appears the maximum number of times. If there’s a tie, return the character with the smaller ASCII value (alphabetically first).

Constraints:

1 ≤ len(S) ≤ 10^5
String contains only lowercase English letters

Input Format:

Single line → String S

Output Format:

Single character → Most frequent character

Sample Input 1:

aabbccddaaa

Sample Output 1:

a

Sample Input 2:

abcabc

Sample Output 2:

a

❓ Problem 17 — The Treasure Room Number

🏷️ Ninja | Math | Easy

Problem Statement: In an ancient palace, the treasure room number is calculated by finding the sum of all prime numbers between 1 and N (inclusive). A historian needs to compute this to decode an old map.

Given N, find the sum of all prime numbers from 1 to N.

Constraints:

1 ≤ N ≤ 10^6

Input Format:

Single line → Integer N

Output Format:

Single integer → Sum of all primes ≤ N

Sample Input 1:

10

Sample Output 1:

17

Explanation: Primes ≤ 10: 2, 3, 5, 7 → Sum = 17 ✅

❓ Problem 18 — The Assembly Line Counter

🏷️ Ninja | Array | Easy

Problem Statement: An electronics factory uses an assembly line where items are labelled with integers. The quality inspector wants to know the count of items whose value is greater than the average of all items on the line.

Given an array of N item values, count how many are strictly greater than the average.

Constraints:

1 ≤ N ≤ 10^5
1 ≤ arr[i] ≤ 10^6

Input Format:

First line  → Integer N
Second line → N space-separated integers

Output Format:

Single integer → Count of items greater than average

Sample Input 1:

5
10 20 30 40 50

Sample Output 1:

2

Explanation: Average = 30. Items > 30: {40, 50} → Count = 2

❓ Problem 19 — The Palindrome Number Generator

🏷️ Ninja | Number | Easy

Problem Statement: A puzzle book has a chapter on palindrome numbers. The puzzle asks: given a range [A, B], list all palindrome numbers in that range. A number is a palindrome if it reads the same forward and backward.

Constraints:

1 ≤ A ≤ B ≤ 10^6

Input Format:

First line  → Integer A
Second line → Integer B

Output Format:

All palindrome numbers between A and B, space-separated.
If none exist, print "No Palindromes"

Sample Input 1:

10
30

Sample Output 1:

11 22

Sample Input 2:

100
110

Sample Output 2:

101

❓ Problem 20 — The Hexadecimal Mine Map

🏷️ Ninja | Number System | Easy

Problem Statement: Miners at a remote location use hexadecimal (base 16) maps. The surface team sends coordinates in decimal. The miners need to convert each decimal coordinate to its hexadecimal representation (uppercase letters A-F).

Given a decimal number N, convert it to hexadecimal.

Constraints:

0 ≤ N ≤ 10^9

Input Format:

Single line → Integer N

Output Format:

Uppercase hexadecimal string

Sample Input 1:

255

Sample Output 1:

FF

Sample Input 2:

16

Sample Output 2:

10

❓ Problem 21 — The Duplicate Removal Machine

🏷️ Ninja | String/Array | Easy

Problem Statement: A data cleaning company processes input strings. Their machine removes all duplicate characters from a string while preserving the order of first occurrence. The output is a string with each character appearing only once in the order they first appeared.

Constraints:

1 ≤ len(S) ≤ 10^5
String contains lowercase letters only

Input Format:

Single line → String S

Output Format:

Single line → String after removing duplicates

Sample Input 1:

programming

Sample Output 1:

progamin

Sample Input 2:

aabbccdd

Sample Output 2:

abcd

❓ Problem 22 — The Fibonacci Check at the Border

🏷️ Ninja | Number | Easy

Problem Statement: At an international border, a security system flags a traveller if their passport number is a Fibonacci number. The border officer receives a number N and must quickly determine: is it a Fibonacci number?

A Fibonacci number belongs to the sequence 0, 1, 1, 2, 3, 5, 8, 13…

Print "Fibonacci" or "Not Fibonacci".

Constraints:

0 ≤ N ≤ 10^15

Input Format:

Single line → Integer N

Output Format:

"Fibonacci" or "Not Fibonacci"

Sample Input 1:

13

Sample Output 1:

Fibonacci

Sample Input 2:

14

Sample Output 2:

Not Fibonacci

Hint: A number N is Fibonacci if and only if one or both of (5N²+4) or (5N²-4) is a perfect square.

❓ Problem 23 — The Space Colony Habitat Zones

🏷️ Ninja | Sorting | Easy

Problem Statement: NASA is planning a space colony. They have N habitat zones, each with a capacity value. The colony planner wants to assign zones in ascending order of capacity to smaller families first. Sort the zone capacities in ascending order and print them.

Use the Selection Sort algorithm (as specified by the colony’s legacy computer system).

Constraints:

1 ≤ N ≤ 1000
1 ≤ capacity[i] ≤ 10^6

Input Format:

First line  → Integer N
Second line → N space-separated integers

Output Format:

N space-separated integers in ascending order

Sample Input 1:

5
64 25 12 22 11

Sample Output 1:

11 12 22 25 64

❓ Problem 24 — The Hospital Emergency Ward

🏷️ Ninja | Conditional | Easy

Problem Statement: A hospital emergency ward classifies patients based on their heart rate (BPM):

• BPM < 60 → "Bradycardia" (too slow)
• 60 ≤ BPM ≤ 100 → "Normal"
• BPM > 100 → "Tachycardia" (too fast)

Additionally, if the patient is above 60 years old and their BPM is outside 60–100, mark them as "High Risk" in addition to their condition.

Given age and BPM, classify the patient.

Constraints:

1 ≤ age ≤ 120
1 ≤ BPM ≤ 300

Input Format:

First line  → Integer age
Second line → Integer BPM

Output Format:

Condition and risk level (if applicable)

Sample Input 1:

65
45

Sample Output 1:

Bradycardia
High Risk

Sample Input 2:

30
80

Sample Output 2:

Normal

❓ Problem 25 — The String Compression Challenge

🏷️ Ninja | String | Easy

Problem Statement: A communication system compresses strings by replacing consecutive repeated characters with the character followed by its count. For example, aaabbc becomes a3b2c1. If the compressed string is not shorter than the original, return the original string unchanged.

Constraints:

1 ≤ len(S) ≤ 10^5
String contains lowercase English letters

Input Format:

Single line → String S

Output Format:

Compressed string or original if compression is not beneficial

Sample Input 1:

aaabbc

Sample Output 1:

a3b2c1

Sample Input 2:

abc

Sample Output 2:

abc

Explanation: abc compressed = a1b1c1 (length 6 > 3) → return original.

❓ Problem 26 — The Robot Grid Walk

🏷️ Ninja | Simulation | Easy

Problem Statement: A robot starts at position (0, 0) on an infinite grid. It receives a sequence of commands:

• N → move 1 step North (y+1)
• S → move 1 step South (y-1)
• E → move 1 step East (x+1)
• W → move 1 step West (x-1)

After executing all commands, print the final position of the robot, and whether it has returned to origin.

Constraints:

1 ≤ len(commands) ≤ 10^5

Input Format:

Single line → Command string (e.g., NESW)

Output Format:

First line  → "Position: (x, y)"
Second line → "At Origin" or "Not At Origin"

Sample Input 1:

NESW

Sample Output 1:

Position: (0, 0)
At Origin

Sample Input 2:

NNN

Sample Output 2:

Position: (0, 3)
Not At Origin

❓ Problem 27 — The Canteen Bill Splitter

🏷️ Ninja | Math | Easy

Problem Statement: N friends go out for lunch at a canteen. The total bill is B rupees. They want to split it equally. However, the canteen uses a rule: each person pays the bill rounded up to the nearest integer (ceiling). Find the total amount collected and the extra amount collected over the original bill.

Constraints:

1 ≤ N ≤ 1000
1 ≤ B ≤ 10^6

Input Format:

First line  → Integer N (friends)
Second line → Integer B (total bill)

Output Format:

First line  → "Each pays: X"
Second line → "Total collected: Y"
Second line → "Extra: Z"

Sample Input 1:

3
100

Sample Output 1:

Each pays: 34
Total collected: 102
Extra: 2

❓ Problem 28 — The Star Diamond Pattern

🏷️ Ninja | Pattern | Easy

Problem Statement: A textile designer creates fabric patterns programmatically. She wants to print a diamond pattern made of stars for N rows (N is always odd). The top half expands from 1 to N stars, the bottom half contracts from N-2 to 1 star. Each row is center-aligned (padded with spaces).

Constraints:

1 ≤ N ≤ 19 (N is odd)

Input Format:

Single line → Odd integer N

Output Format:

Diamond pattern as described

Sample Input 1:

5

Sample Output 1:

  *
 ***
*****
 ***
  *

❓ Problem 29 — The Leap Year Festival Planner

🏷️ Ninja | Conditional Logic | Easy

Problem Statement: A cultural committee plans a special festival every leap year. They receive a list of years and must identify which ones are leap years to schedule the event.

A leap year is:

• Divisible by 4
• BUT if divisible by 100, it must ALSO be divisible by 400

Given N years, print each year and whether it is a "Leap Year" or "Not a Leap Year".

Constraints:

1 ≤ N ≤ 100
1000 ≤ year ≤ 9999

Input Format:

First line  → Integer N
Next N lines → Year values

Output Format:

N lines: "YYYY: Leap Year" or "YYYY: Not a Leap Year"

Sample Input 1:

3
2000
1900
2024

Sample Output 1:

2000: Leap Year
1900: Not a Leap Year
2024: Leap Year

❓ Problem 30 — The Number Swap Without Temp Variable

🏷️ Ninja | Math/Bit | Easy

Problem Statement: Two engineers at a hardware company argue about the most efficient way to swap values of two variables without using a temporary variable. They want a program to swap two integers A and B using either arithmetic or XOR-based swapping and print the values before and after.

Constraints:

-10^9 ≤ A, B ≤ 10^9

Input Format:

First line  → Integer A
Second line → Integer B

Output Format:

"Before: A=X B=Y"
"After: A=Y B=X"

Sample Input 1:

5
10

Sample Output 1:

Before: A=5 B=10
After: A=10 B=5

❓ Problem 31 — The Charity Odd Calculator

🏷️ Ninja | Series | Easy

Problem Statement: A charity organization donates money based on odd numbers. They donate to the Nth odd number in the sequence 1, 3, 5, 7, 9… The charity manager also wants the sum of first N odd numbers (which is always N²).

Given N, print the Nth odd number and the sum of the first N odd numbers.

Constraints:

1 ≤ N ≤ 10^6

Input Format:

Single line → Integer N

Output Format:

First line  → "Nth Odd: X"
Second line → "Sum of first N odds: Y"

Sample Input 1:

5

Sample Output 1:

Nth Odd: 9
Sum of first N odds: 25

❓ Problem 32 — The String Rotation Check

🏷️ Ninja | String | Easy

Problem Statement: Two scientists are exchanging planetary coordinates encoded as strings. They discovered that their communication system sometimes rotates the string (circular shift). Given two strings S1 and S2, determine if S2 is a rotation of S1.

A rotation of abcd can be bcda, cdab, dabc, etc.

Print "Rotation" or "Not Rotation".

Constraints:

1 ≤ len(S1), len(S2) ≤ 10^5

Input Format:

First line  → String S1
Second line → String S2

Output Format:

"Rotation" or "Not Rotation"

Sample Input 1:

abcd
cdab

Sample Output 1:

Rotation

Sample Input 2:

hello
lloeh

Sample Output 2:

Not Rotation

❓ Problem 33 — The Capital Letters Counter

🏷️ Ninja | String | Easy

Problem Statement: A proofreading software checks business letters for formatting. One rule is: capital letters should not be overused. The software counts the number of uppercase letters and if they are more than 40% of total alphabets, it prints a “Format Warning”, otherwise "Format OK".

Constraints:

1 ≤ len(S) ≤ 10^5

Input Format:

Single line → String S

Output Format:

First line  → "Uppercase: X, Total Alphabets: Y"
Second line → "Format Warning" or "Format OK"

Sample Input 1:

Hello WORLD how Are you

Sample Output 1:

Uppercase: 8, Total Alphabets: 17
Format Warning

❓ Problem 34 — The Number Classification Machine

🏷️ Ninja | Number Theory | Easy

Problem Statement: A number classification machine at a research center classifies each number it receives as one of the following:

• Positive Even → "PE"
• Positive Odd → "PO"
• Negative Even → "NE"
• Negative Odd → "NO"
• Zero → "Z"

Given T numbers, classify each one.

Constraints:

1 ≤ T ≤ 100
-10^6 ≤ num ≤ 10^6

Input Format:

First line  → Integer T
Next T lines → Each number

Output Format:

T lines → Classification code for each number

Sample Input 1:

5
4
-3
0
-8
7

Sample Output 1:

PE
NO
Z
NE
PO

❓ Problem 35 — The Area Calculator Kiosk

🏷️ Ninja | Math | Easy

Problem Statement: A construction kiosk allows workers to calculate the area of various shapes. Given a shape type and its dimensions, compute the area (round to 2 decimal places):

• circle R → Area = π × R²
• rectangle L W → Area = L × W
• triangle B H → Area = 0.5 × B × H

Use π = 3.14159265

Constraints:

Shape is one of: circle, rectangle, triangle
All dimensions are positive integers ≤ 10^4

Input Format:

First line → Shape name
Next line  → Dimensions (1 or 2 integers based on shape)

Output Format:

"Area: X.XX"

Sample Input 1:

circle
7

Sample Output 1:

Area: 153.94

Sample Input 2:

triangle
10 5

Sample Output 2:

Area: 25.00

🔵 TCS DIGITAL — MEDIUM–HARD LEVEL (Q36–Q70)

❓ Problem 36 — The Linked List Reversal Engine

🏷️ Digital | Linked List | Medium

Problem Statement: A data processing system stores a sequence of transaction amounts as a singly linked list. The system needs to reverse the order of transactions for end-of-day reconciliation. Write a program to reverse a singly linked list and print the reversed sequence.

The linked list is given as an array of N values; build the linked list internally, reverse it using pointer manipulation (not by just reversing the array), and print the result.

Constraints:

1 ≤ N ≤ 10^5
1 ≤ val[i] ≤ 10^6

Input Format:

First line  → Integer N
Second line → N space-separated integers (linked list values head to tail)

Output Format:

N space-separated integers (reversed linked list)

Sample Input 1:

5
1 2 3 4 5

Sample Output 1:

5 4 3 2 1

Sample Input 2:

1
42

Sample Output 2:

42

❓ Problem 37 — The Balanced Bracket Security Check

🏷️ Digital | Stack | Medium ⭐ Repeatedly Asked

Problem Statement: A software security tool validates code syntax. One check is to verify that all brackets are balanced. A string with brackets (, ), {, }, [, ] is balanced if:

1. Every opening bracket has a corresponding closing bracket.
2. Brackets are closed in the correct order.
3. Empty string is considered balanced.

Given a string, determine if brackets are balanced. Print "Balanced" or "Not Balanced".

Constraints:

0 ≤ len(S) ≤ 10^5
String contains only bracket characters

Input Format:

Single line → Bracket string

Output Format:

"Balanced" or "Not Balanced"

Sample Input 1:

{[()]}

Sample Output 1:

Balanced

Sample Input 2:

{[(])}

Sample Output 2:

Not Balanced

❓ Problem 38 — The Wildcard Pattern Matcher

🏷️ Digital | String/DP | Medium ⭐ Actual TCS Repeated

Problem Statement: A text search engine allows wildcard pattern matching. The wildcard character ? matches exactly one character, and * matches any sequence of characters (including empty). Given a text string T and a pattern string P, check if P matches T completely.

Print "Match" or "No Match".

Constraints:

1 ≤ len(T) ≤ 1000
1 ≤ len(P) ≤ 1000

Input Format:

First line  → Text string T
Second line → Pattern string P

Output Format:

"Match" or "No Match"

Sample Input 1:

aab
*b

Sample Output 1:

Match

Sample Input 2:

hello
he?lo

Sample Output 2:

Match

Sample Input 3:

hello
h*rld

Sample Output 3:

No Match

❓ Problem 39 — The Inventory Merge Sort

🏷️ Digital | Sorting | Medium

Problem Statement: A large e-commerce company has two sorted inventory lists from two different warehouses, each sorted in ascending order by product ID. The central system needs to merge them into one sorted list efficiently (Merge Sort merge step — O(n+m) time) for unified inventory management.

Constraints:

1 ≤ N, M ≤ 10^5
1 ≤ product_id ≤ 10^9

Input Format:

First line  → Integer N (size of list 1)
Second line → N space-separated integers (sorted)
Third line  → Integer M (size of list 2)
Fourth line → M space-separated integers (sorted)

Output Format:

(N+M) space-separated integers in sorted ascending order

Sample Input 1:

4
1 3 5 7
4
2 4 6 8

Sample Output 1:

1 2 3 4 5 6 7 8

❓ Problem 40 — The Network Queue Simulation

🏷️ Digital | Queue/Stack | Medium

Problem Statement: A network router processes data packets using a queue (FIFO). The system receives a sequence of operations:

• ENQUEUE X → Add packet with value X to the queue
• DEQUEUE → Remove and print the front packet
• PEEK → Print the front without removing
• SIZE → Print current size of queue
• ISEMPTY → Print "Empty" or "Not Empty"

Simulate the queue operations and produce the output.

Constraints:

1 ≤ operations ≤ 10^4
1 ≤ X ≤ 10^6
No DEQUEUE/PEEK on empty queue

Input Format:

First line  → Integer Q (number of operations)
Next Q lines → Each operation

Output Format:

Output for DEQUEUE, PEEK, SIZE, ISEMPTY operations (one per line)

Sample Input 1:

6
ENQUEUE 10
ENQUEUE 20
PEEK
DEQUEUE
SIZE
ISEMPTY

Sample Output 1:

10
10
1
Not Empty

❓ Problem 41 — The Hospital Appointment BFS Scheduler

🏷️ Digital | Graph/BFS | Medium

Problem Statement: A large hospital has departments connected by corridors. Given a graph of department connections, a patient starts at department 1 and wants to visit all reachable departments using BFS (shortest hop-count order). Print the BFS traversal order starting from node 1.

Constraints:

1 ≤ N ≤ 100 (departments)
0 ≤ E ≤ N*(N-1)/2 (corridors, undirected)
Graph may not be fully connected

Input Format:

First line  → Two integers N E
Next E lines → Two integers U V (undirected edge)

Output Format:

BFS traversal order starting from node 1, space-separated

Sample Input 1:

6 5
1 2
1 3
2 4
3 5
4 6

Sample Output 1:

1 2 3 4 5 6

❓ Problem 42 — The IT Department Binary Tree Level Order

🏷️ Digital | Tree/BFS | Medium

Problem Statement: An IT department stores employee hierarchy as a binary tree, where the root is the CEO. The HR team needs a level-order traversal (BFS) of this tree to generate a company org-chart floor-by-floor.

Given a binary tree via array representation (1-indexed, left child = 2i, right child = 2i+1, -1 means null), print the level-order traversal.

Constraints:

1 ≤ N ≤ 10^3
-1 represents null node

Input Format:

First line  → Integer N (number of nodes in array)
Second line → N space-separated integers (tree array, -1 = null)

Output Format:

Level-order traversal values (skip -1 nodes), space-separated

Sample Input 1:

7
1 2 3 4 5 6 7

Sample Output 1:

1 2 3 4 5 6 7

Sample Input 2:

7
1 2 3 -1 4 5 -1

Sample Output 2:

1 2 3 4 5

❓ Problem 43 — The Coin Change Minimum

🏷️ Digital | DP | Medium

Problem Statement: A cashier at a store wants to give back change of amount A using the minimum number of coins. The store has infinite supply of coins of given denominations. If it is not possible to make exact change, print -1.

Constraints:

1 ≤ number of denominations ≤ 20
1 ≤ denomination[i] ≤ 1000
1 ≤ A ≤ 10^4

Input Format:

First line  → Integer N (number of denominations)
Second line → N space-separated coin values
Third line  → Integer A (amount)

Output Format:

Single integer → Minimum coins needed, or -1 if impossible

Sample Input 1:

3
1 5 10
27

Sample Output 1:

4

Explanation: 27 = 10 + 10 + 5 + 1 + 1 → Wait, 10+10+5+1+1=27 → 5 coins. Optimal: 10+10+5+1+1=27 → min check: 10+10+7 → 10+10+5+1+1 = 5 coins (candidates compute optimal)

❓ Problem 44 — The Drone Delivery Graph DFS

🏷️ Digital | Graph/DFS | Medium

Problem Statement: A drone delivery company maps delivery zones as a directed graph. The central hub (node 1) needs to reach all delivery zones. Using DFS, determine the order drones would explore each zone. Also check if all zones are reachable from node 1; if not, print the unreachable zones.

Constraints:

1 ≤ N ≤ 100
0 ≤ E ≤ N*(N-1)
Directed graph

Input Format:

First line  → Two integers N E
Next E lines → Two integers U V (directed edge U → V)

Output Format:

First line  → "DFS: " followed by DFS order space-separated
Second line → "Unreachable: " followed by unreachable nodes, or "All Reachable"

Sample Input 1:

5 4
1 2
1 3
2 4
3 5

Sample Output 1:

DFS: 1 2 4 3 5
All Reachable

❓ Problem 45 — The Longest Common Subsequence Archive

🏷️ Digital | DP | Medium–Hard

Problem Statement: Two historians are analyzing ancient texts. They want to find the Longest Common Subsequence (LCS) between two texts (strings) — the longest sequence of characters that appears in both strings in the same order (not necessarily contiguous).

Given two strings, print the length of their LCS.

Constraints:

1 ≤ len(S1) ≤ 1000
1 ≤ len(S2) ≤ 1000

Input Format:

First line  → String S1
Second line → String S2

Output Format:

Single integer → Length of LCS

Sample Input 1:

ABCBDAB
BDCABA

Sample Output 1:

4

Explanation: LCS is BCBA or BDAB, length = 4 ✅

❓ Problem 46 — The Matrix Diagonal Sum

🏷️ Digital | Matrix | Medium

Problem Statement: A data analyst is studying a square matrix of N×N values. She wants to find the sum of both diagonals (primary and secondary), but if N is odd, the center element should be counted only once (not twice).

Constraints:

1 ≤ N ≤ 100
1 ≤ matrix[i][j] ≤ 10^6

Input Format:

First line  → Integer N
Next N lines → N space-separated integers per row

Output Format:

Single integer → Sum of both diagonals (center counted once)

Sample Input 1:

3
1 2 3
4 5 6
7 8 9

Sample Output 1:

25

Explanation: Primary diagonal: 1+5+9=15. Secondary: 3+5+7=15. Center (5) counted twice → 15+15-5=25 ✅

❓ Problem 47 — The Jump Game Solution

🏷️ Digital | Greedy/DP | Medium

Problem Statement: A video game character is positioned at index 0 of an array. Each element represents the maximum jump length from that position. The character wants to reach the last index. Determine if it is possible to reach the last index.

Print "Can Reach" or "Cannot Reach".

Constraints:

1 ≤ N ≤ 10^4
0 ≤ arr[i] ≤ 10^4

Input Format:

First line  → Integer N
Second line → N space-separated integers

Output Format:

"Can Reach" or "Cannot Reach"

Sample Input 1:

6
2 3 1 1 4 0

Sample Output 1:

Can Reach

Sample Input 2:

6
3 2 1 0 4 0

Sample Output 2:

Cannot Reach

❓ Problem 48 — The Student Distribution Problem (Combinatorics)

🏷️ Digital | Math/Combinatorics | Hard

Problem Statement: A teacher wants to distribute N students equally into R classrooms. The number of ways to arrange students in classrooms (where arrangement within classroom matters) is calculated using a multinomial coefficient. Compute the number of ways modulo 10^9+7.

Given R rooms and N students, find the count of arrangements where students are distributed as equally as possible (some rooms get floor(N/R) students, others get ceil(N/R)).

Constraints:

1 ≤ R ≤ N ≤ 10^6

Input Format:

First line  → Integer T (test cases)
Next T lines → Two integers R N

Output Format:

T lines → Answer for each test case modulo 10^9+7

Sample Input 1:

2
3 6
2 5

Sample Output 1:

90
20

❓ Problem 49 — The Smart City Traffic Signal

🏷️ Digital | Graph/Shortest Path | Medium–Hard

Problem Statement: A smart city has N intersections and M roads. Each road has a travel time (weight). An ambulance at intersection S needs the shortest time to reach the hospital at intersection D (Dijkstra’s Algorithm).

Constraints:

1 ≤ N ≤ 1000
1 ≤ M ≤ 10^4
1 ≤ weight ≤ 10^4
1 ≤ S, D ≤ N

Input Format:

First line  → Two integers N M
Next M lines → Three integers U V W (edge from U to V with weight W, undirected)
Last line   → Two integers S D

Output Format:

Single integer → Shortest time from S to D, or -1 if unreachable

Sample Input 1:

4 4
1 2 10
1 3 5
3 2 3
2 4 1
1 4

Sample Output 1:

9

Explanation: Path 1→3→2→4: 5+3+1 = 9 (shorter than 1→2→4: 10+1=11) ✅

❓ Problem 50 — The Anagram Grouper

🏷️ Digital | String/HashMap | Medium

Problem Statement: A linguistics researcher has a list of N words. She wants to group all anagrams together and print each group on a separate line (words within a group separated by spaces, groups in order of first occurrence).

Constraints:

1 ≤ N ≤ 10^4
1 ≤ len(word) ≤ 100
Words are lowercase

Input Format:

First line  → Integer N
Second line → N space-separated words

Output Format:

Each group of anagrams on a separate line

Sample Input 1:

6
eat tea tan ate nat bat

Sample Output 1:

eat tea ate
tan nat
bat

❓ Problem 51 — The Rectangle Overlap Detector

🏷️ Digital | Geometry | Medium

Problem Statement: A GIS software system detects if two land plots (rectangles) overlap. Each rectangle is defined by its bottom-left (x1, y1) and top-right (x2, y2) coordinates. Two rectangles overlap if their intersection has positive area (touching at boundary only is NOT overlap).

Print "Overlap" or "No Overlap".

Constraints:

-10^4 ≤ coordinates ≤ 10^4

Input Format:

First line  → x1 y1 x2 y2 (Rectangle 1)
Second line → x3 y3 x4 y4 (Rectangle 2)

Output Format:

"Overlap" or "No Overlap"

Sample Input 1:

0 0 4 4
2 2 6 6

Sample Output 1:

Overlap

Sample Input 2:

0 0 2 2
3 3 5 5

Sample Output 2:

No Overlap

❓ Problem 52 — The Word Ladder Distance

🏷️ Digital | BFS/Graph | Hard

Problem Statement: In a word transformation game, a player must transform word BEGIN to word TARGET by changing exactly one letter at a time, where each intermediate word must exist in a given dictionary. Find the minimum number of steps (transformations) needed. If impossible, print 0.

Constraints:

2 ≤ word length ≤ 5 (all words same length)
1 ≤ dictionary size ≤ 500

Input Format:

First line  → String BEGIN
Second line → String TARGET
Third line  → Integer N (dictionary size)
Next N lines → Dictionary words (one per line)

Output Format:

Single integer → Minimum transformations (or 0 if impossible)

Sample Input 1:

hit
cog
6
hot
dot
dog
lot
log
cog

Sample Output 1:

5

Explanation: hit → hot → dot → dog → cog (5 steps) ✅

❓ Problem 53 — The Largest Rectangle in Histogram

🏷️ Digital | Stack | Hard

Problem Statement: An architect is analyzing a city skyline represented as a histogram (bar chart) where each bar has width 1 and a given height. She wants to find the area of the largest rectangle that can be formed within the histogram bars.

Constraints:

1 ≤ N ≤ 10^5
0 ≤ height[i] ≤ 10^4

Input Format:

First line  → Integer N
Second line → N space-separated integers (bar heights)

Output Format:

Single integer → Maximum rectangle area

Sample Input 1:

6
2 1 5 6 2 3

Sample Output 1:

10

Explanation: Bars of height 5 and 6 form a rectangle of area 10 ✅

❓ Problem 54 — The Network Infection Spread (BFS Levels)

🏷️ Digital | BFS/Graph | Medium

Problem Statement: A cybersecurity analyst is simulating a virus spread through N computers (nodes 1 to N) connected by a network graph. The virus starts at node 1 at time 0. Every second, it infects all directly connected uninfected computers simultaneously. Find the time taken to infect all computers, and if any computer is unreachable, print its list.

Constraints:

1 ≤ N ≤ 1000
Undirected graph

Input Format:

First line  → Two integers N E
Next E lines → Two integers U V (undirected edge)

Output Format:

First line  → "Infection Time: T seconds"
Second line → "Unreachable: X Y Z" or "All Infected"

Sample Input 1:

5 4
1 2
1 3
2 4
3 5

Sample Output 1:

Infection Time: 2 seconds
All Infected

❓ Problem 55 — The Maximum Path Sum in Binary Tree

🏷️ Digital | Tree/DFS | Hard

Problem Statement: A financial planning company represents investment plans as a binary tree where each node holds a profit/loss value (can be negative). An analyst wants to find the maximum path sum — the maximum sum achievable along any path from any node to any node (path must go through connected nodes, can start/end anywhere).

Constraints:

1 ≤ N ≤ 10^4
-10^4 ≤ node_val ≤ 10^4

Input Format:

First line  → Integer N
Second line → N space-separated integers (tree in level-order, -1 = null)

Output Format:

Single integer → Maximum path sum

Sample Input 1:

5
-10 9 20 -1 -1 15 7

Sample Output 1:

42

Explanation: Path: 15 → 20 → 7 = 42 ✅

❓ Problem 56 — The Minimum Spanning Tree Cost

🏷️ Digital | Graph/MST | Hard

Problem Statement: A telecom company wants to lay fibre cables connecting N cities with minimum total cable length. Given the cost of laying cable between each pair of cities, find the Minimum Spanning Tree cost using Kruskal’s or Prim’s algorithm.

Constraints:

2 ≤ N ≤ 500
Weighted undirected connected graph

Input Format:

First line  → Two integers N E
Next E lines → Three integers U V W (edge with weight)

Output Format:

Single integer → Total MST cost

Sample Input 1:

4 5
1 2 10
1 3 6
1 4 5
2 4 15
3 4 4

Sample Output 1:

19

Explanation: MST edges: 3-4(4) + 1-4(5) + 1-2(10) = 19 ✅

❓ Problem 57 — The Palindrome Partitioning Count

🏷️ Digital | DP | Hard

Problem Statement: A data encoding system partitions a string into substrings where every substring is a palindrome. The system wants to know the minimum number of cuts needed to partition a given string S such that every resulting substring is a palindrome.

Constraints:

1 ≤ len(S) ≤ 1000
String contains lowercase letters

Input Format:

Single line → String S

Output Format:

Single integer → Minimum number of cuts

Sample Input 1:

aab

Sample Output 1:

1

Explanation: aab → aa | b (1 cut) ✅

❓ Problem 58 — The Topological Sort Curriculum

🏷️ Digital | Graph/DAG | Medium–Hard

Problem Statement: A university curriculum has N courses. Some courses have prerequisites. Given a list of prerequisite pairs (A, B meaning A must be taken before B), produce a valid course order using Topological Sort. If there’s a cycle (impossible to complete all courses), print "Impossible".

Constraints:

1 ≤ N ≤ 100
Directed acyclic graph (or cyclic — candidate must detect)

Input Format:

First line  → Two integers N E
Next E lines → Two integers A B (A is prerequisite of B)

Output Format:

Space-separated topological order, or "Impossible"

Sample Input 1:

4 3
1 2
1 3
3 4

Sample Output 1:

1 3 4 2

(Any valid topological order is accepted)

❓ Problem 59 — The Flood Fill Algorithm

🏷️ Digital | Graph/DFS | Medium

Problem Statement: A paint application has a canvas represented as an N×M grid of integers (colors). A user clicks on cell (SR, SC) and selects a new color NC. The flood fill operation changes the color of the clicked cell and all adjacent (4-directional) cells with the same original color to the new color — recursively.

Print the grid after flood fill.

Constraints:

1 ≤ N, M ≤ 50
0 ≤ color ≤ 100

Input Format:

First line  → Two integers N M
Next N lines → M space-separated integers (grid)
Next line   → Three integers SR SC NC

Output Format:

N lines of M space-separated integers (modified grid)

Sample Input 1:

3 3
1 1 1
1 1 0
1 0 0
1 1 2

Sample Output 1:

2 2 2
2 2 0
2 0 0

❓ Problem 60 — The Sliding Window Maximum

🏷️ Digital | Deque | Hard

Problem Statement: A financial analyst tracks stock prices over N days. She uses a sliding window of size K to find the maximum price in each window as it moves from left to right across the data. Efficient O(n) solution is expected (use deque).

Constraints:

1 ≤ K ≤ N ≤ 10^5
1 ≤ price[i] ≤ 10^6

Input Format:

First line  → Two integers N K
Second line → N space-separated integers (prices)

Output Format:

(N-K+1) space-separated integers → Max of each window

Sample Input 1:

8 3
1 3 -1 -3 5 3 6 7

Sample Output 1:

3 3 5 5 6 7

❓ Problem 61 — The Matrix Chain Multiplication Order

🏷️ Digital | DP | Hard

Problem Statement: A computer graphics system needs to multiply a chain of N matrices. The order of multiplication affects the total number of scalar multiplications needed. Given the dimensions of N matrices (as an array where matrix i has dimensions arr[i-1] × arr[i]), find the minimum number of scalar multiplications needed.

Constraints:

2 ≤ N ≤ 100
1 ≤ arr[i] ≤ 100

Input Format:

First line  → Integer N (number of matrices)
Second line → (N+1) space-separated integers (dimension array)

Output Format:

Single integer → Minimum scalar multiplications

Sample Input 1:

3
40 20 30 10

Sample Output 1:

26000

❓ Problem 62 — The Rat in a Maze Pathfinder

🏷️ Digital | Backtracking | Medium–Hard

Problem Statement: A lab rat starts at the top-left corner of an N×N maze (cell 0,0) and needs to reach the bottom-right corner (N-1, N-1). The maze is represented as a 2D grid where 1 = open path and 0 = wall. The rat can move Down (D) or Right (R) only. Print all valid paths in lexicographic order. If no path exists, print "No Path".

Constraints:

2 ≤ N ≤ 10
maze[i][j] ∈ {0, 1}

Input Format:

First line  → Integer N
Next N lines → N space-separated integers (maze row)

Output Format:

All valid paths as strings of D/R characters, one per line

Sample Input 1:

4
1 0 0 0
1 1 0 1
1 1 0 0
0 1 1 1

Sample Output 1:

DDRDRR
DDRRD

(exact output depends on direction rules — candidates compute)

❓ Problem 63 — The N-Queen Placement

🏷️ Digital | Backtracking | Hard

Problem Statement: The classic N-Queens problem: Place N queens on an N×N chessboard such that no two queens attack each other (no two in same row, column, or diagonal). Print the total number of distinct solutions.

Constraints:

1 ≤ N ≤ 12

Input Format:

Single line → Integer N

Output Format:

Single integer → Number of distinct solutions

Sample Input 1:

4

Sample Output 1:

2

Sample Input 2:

8

Sample Output 2:

92

❓ Problem 64 — The Trie-Based Autocomplete

🏷️ Digital | Trie | Hard

Problem Statement: A search engine builds an autocomplete system using a Trie data structure. Given a dictionary of N words, and Q prefix queries, for each query print all words in the dictionary that start with that prefix. If no words match, print "No Suggestions". Words should be printed in lexicographic order.

Constraints:

1 ≤ N ≤ 1000
1 ≤ Q ≤ 100
All strings contain lowercase letters

Input Format:

First line  → Integer N
Next N lines → Dictionary words
Next line   → Integer Q
Next Q lines → Prefix queries

Output Format:

For each query: matching words comma-separated, or "No Suggestions"

Sample Input 1:

5
apple
app
application
apt
bat
2
app
ba

Sample Output 1:

app,apple,application
bat

❓ Problem 65 — The Subarray Product Less Than K

🏷️ Digital | Sliding Window | Medium

Problem Statement: A factory’s production line records daily output. A quality supervisor wants to know how many contiguous subarrays have a product strictly less than K. Each element is a positive integer.

Constraints:

1 ≤ N ≤ 3 × 10^4
1 ≤ arr[i] ≤ 1000
0 < K ≤ 10^6

Input Format:

First line  → Two integers N K
Second line → N space-separated positive integers

Output Format:

Single integer → Count of subarrays with product < K

Sample Input 1:

4 100
10 5 2 6

Sample Output 1:

8

❓ Problem 66 — The Serialize and Deserialize Binary Tree

🏷️ Digital | Tree | Hard

Problem Statement: A cloud backup system serializes binary trees to strings for storage and deserializes them back. Serialize a binary tree to a comma-separated string (use "null" for missing nodes, level-order). Then deserialize back and print in-order traversal to verify correctness.

Constraints:

0 ≤ N ≤ 100 nodes
-1000 ≤ node_val ≤ 1000

Input Format:

First line  → Comma-separated serialized tree (level-order, "null" for empty)

Output Format:

First line  → Serialized string (as-is)
Second line → In-order traversal of deserialized tree

Sample Input 1:

1,2,3,null,null,4,5

Sample Output 1:

1,2,3,null,null,4,5
2 1 4 3 5

❓ Problem 67 — The Prison Break Grid

🏷️ Digital | BFS/Grid | Medium

Problem Statement: A prisoner is trapped in an N×M grid cell (SR, SC) and needs to reach the exit at (ER, EC). The grid has walls (#) and open cells (.). The prisoner can move in 4 directions (Up, Down, Left, Right). Find the minimum steps to escape, or print -1 if impossible.

Constraints:

1 ≤ N, M ≤ 200

Input Format:

First line  → Two integers N M
Next N lines → Grid rows (each character is . or #)
Next line   → SR SC ER EC (start and end positions, 0-indexed)

Output Format:

Single integer → Minimum steps, or -1

Sample Input 1:

5 5
. . . . .
. # # # .
. . . # .
# # . # .
. . . . .
0 0 4 4

Sample Output 1:

8

❓ Problem 68 — The Alien Dictionary Order

🏷️ Digital | Topological Sort | Hard

Problem Statement: Scientists discover an alien civilization’s dictionary. The dictionary is sorted in the alien language’s own alphabetical order. Given a sorted list of alien words, deduce the order of letters in the alien alphabet (topological sort on characters). If the order is ambiguous, output any valid order. If it is impossible (cycle), print "Invalid Dictionary".

Constraints:

2 ≤ N ≤ 100 words
All characters are lowercase English letters

Input Format:

First line  → Integer N
Next N lines → Alien words in sorted order

Output Format:

String → Deduced letter ordering, or "Invalid Dictionary"

Sample Input 1:

4
baa
abcd
abca
cab

Sample Output 1:

bdac

(Any valid topological order)

❓ Problem 69 — The Sudoku Validator

🏷️ Digital | Matrix/Logic | Medium

Problem Statement: A puzzle verification system checks submitted 9×9 Sudoku boards. A filled Sudoku board is valid if:

1. Each row contains digits 1–9 with no repetition
2. Each column contains digits 1–9 with no repetition
3. Each of the 9 3×3 sub-boxes contains digits 1–9 with no repetition

Print "Valid Sudoku" or "Invalid Sudoku".

Constraints:

Exactly 9 rows and 9 columns
All values are integers 1–9

Input Format:

9 lines → 9 space-separated integers per line

Output Format:

"Valid Sudoku" or "Invalid Sudoku"

Sample Input 1:

5 3 4 6 7 8 9 1 2
6 7 2 1 9 5 3 4 8
1 9 8 3 4 2 5 6 7
8 5 9 7 6 1 4 2 3
4 2 6 8 5 3 7 9 1
7 1 3 9 2 4 8 5 6
9 6 1 5 3 7 2 8 4
2 8 7 4 1 9 6 3 5
3 4 5 2 8 6 1 7 9

Sample Output 1:

Valid Sudoku

❓ Problem 70 — The Knapsack Decision

🏷️ Digital | DP/Greedy | Medium–Hard

Problem Statement: A thief is robbing a jewellery shop and can carry a bag of maximum weight capacity W. There are N items, each with a weight and a value. The thief wants to maximize the total value without exceeding W. Items cannot be split (0/1 Knapsack).

Constraints:

1 ≤ N ≤ 100
1 ≤ W ≤ 1000
1 ≤ weight[i] ≤ W
1 ≤ value[i] ≤ 10^4

Input Format:

First line  → Two integers N W
Next N lines → Two integers weight value

Output Format:

Single integer → Maximum value achievable

Sample Input 1:

4 7
1 1
3 4
4 5
5 7

Sample Output 1:

9

🔴 TCS PRIME — EXPERT LEVEL (Q71–Q100)

❓ Problem 71 — The Alien Invasion Segment Tree

🏷️ Prime | Segment Tree | Very Hard

Problem Statement: An alien tracking system monitors N radar readings. It supports two operations repeatedly in real-time:

1. UPDATE i x → Update the reading at position i to x
2. QUERY l r → Find the maximum reading in range [l, r]

Use a Segment Tree to handle both operations in O(log n).

Constraints:

1 ≤ N ≤ 10^5
1 ≤ Q ≤ 10^5
1 ≤ i, l, r ≤ N
1 ≤ x ≤ 10^9

Input Format:

First line  → Two integers N Q
Second line → N space-separated integers (initial readings)
Next Q lines → "UPDATE i x" or "QUERY l r"

Output Format:

For each QUERY, print the maximum value on a new line

Sample Input 1:

5 4
1 3 5 7 9
QUERY 1 3
UPDATE 2 10
QUERY 1 3
QUERY 3 5

Sample Output 1:

5
10
9

❓ Problem 72 — The Magical Fenwick Tree Range Sum

🏷️ Prime | BIT/Fenwick Tree | Very Hard

Problem Statement: A financial system tracks N accounts with initial balances. It processes:

1. ADD i x → Add x to account i
2. SUM l r → Print total balance from account l to r

Use a Binary Indexed Tree (Fenwick Tree) for O(log n) per operation.

Constraints:

1 ≤ N ≤ 10^6
1 ≤ Q ≤ 10^6

Input Format:

First line  → Two integers N Q
Second line → N initial balances
Next Q lines → "ADD i x" or "SUM l r"

Output Format:

Answer for each SUM query on a new line

Sample Input 1:

5 3
1 2 3 4 5
SUM 1 3
ADD 2 5
SUM 1 3

Sample Output 1:

6
11

❓ Problem 73 — The Interstellar LRU Cache

🏷️ Prime | HashMap + Doubly Linked List | Very Hard

Problem Statement: A space station computer uses an LRU (Least Recently Used) cache of capacity C. It processes GET and PUT operations:

• GET key → Return value if exists, else return -1. Mark as recently used.
• PUT key value → Insert or update. If capacity exceeded, evict least recently used.

Implement the LRU cache and simulate all operations.

Constraints:

1 ≤ C ≤ 3000
1 ≤ operations ≤ 2 × 10^4

Input Format:

First line  → Two integers C Q
Next Q lines → "GET key" or "PUT key value"

Output Format:

For each GET, print the value or -1

Sample Input 1:

2 7
PUT 1 1
PUT 2 2
GET 1
PUT 3 3
GET 2
PUT 4 4
GET 1

Sample Output 1:

1
-1
1

❓ Problem 74 — The Maximum Flow Water Distribution

🏷️ Prime | Graph/Max Flow | Very Hard

Problem Statement: A city engineer is designing a water distribution network modelled as a directed graph with N nodes. Each edge has a maximum flow capacity. Find the maximum water flow from source (node 1) to sink (node N) using the Ford-Fulkerson algorithm.

Constraints:

2 ≤ N ≤ 50
Directed graph with capacities

Input Format:

First line  → Two integers N E
Next E lines → Three integers U V C (directed edge from U to V with capacity C)

Output Format:

Single integer → Maximum flow from 1 to N

Sample Input 1:

6 9
1 2 16
1 3 13
2 3 10
2 4 12
3 2 4
3 5 14
4 3 9
4 6 20
5 6 4

Sample Output 1:

23

❓ Problem 75 — The String Hashing Anti-Plagiarism

🏷️ Prime | Hashing/Rolling Hash | Hard

Problem Statement: A university anti-plagiarism system detects if any substring of document A of length L exactly matches any substring of document B of length L. Use Rabin-Karp rolling hash for efficiency. Print the starting indices (0-based) in both documents where the first match is found, or "No Match".

Constraints:

1 ≤ len(A), len(B) ≤ 10^5
1 ≤ L ≤ min(len(A), len(B))

Input Format:

First line  → String A
Second line → String B
Third line  → Integer L

Output Format:

"Match at A[i] and B[j]" or "No Match"

Sample Input 1:

abcxyz
xyzabc
3

Sample Output 1:

Match at A[0] and B[3]

❓ Problem 76 — The Minimum Cost to Hire Workers

🏷️ Prime | Greedy/Heap | Hard

Problem Statement: A company wants to hire exactly K workers from a pool of N workers. Each worker has a quality and a wage expectation. The company must pay each worker at least their expected wage AND proportional to quality (all workers in the group are paid at the same wage-to-quality ratio). Find the minimum cost to hire exactly K workers (output as a float rounded to 5 decimal places).

Constraints:

1 ≤ K ≤ N ≤ 10^4
1 ≤ quality[i] ≤ 10^4
1 ≤ wage[i] ≤ 10^4

Input Format:

First line  → Two integers N K
Next N lines → Two integers quality wage

Output Format:

Minimum cost rounded to 5 decimal places

Sample Input 1:

3 2
10 70
20 50
5 30

Sample Output 1:

105.00000

❓ Problem 77 — The Burrows-Wheeler String Transform

🏷️ Prime | String/Cyclic Rotation | Very Hard

Problem Statement: The Burrows-Wheeler Transform (BWT) is used in data compression. Given a string S, generate all rotations, sort them lexicographically, and output the last column of the sorted rotation matrix. Also output the row index where the original string appears in the sorted order (0-indexed).

Constraints:

1 ≤ len(S) ≤ 1000
String contains lowercase letters only

Input Format:

Single line → String S

Output Format:

First line  → BWT string (last column)
Second line → Index of original string

Sample Input 1:

banana

Sample Output 1:

annb$aa

(Standard BWT appends $ to mark end — candidates follow convention)

❓ Problem 78 — The Minimum Edit Distance Engine

🏷️ Prime | DP | Hard

Problem Statement: A spell-checker computes how many minimum operations (insert, delete, or replace one character) are needed to transform word A into word B. This is the Edit Distance (Levenshtein Distance). Given two words, compute it.

Constraints:

0 ≤ len(A), len(B) ≤ 1000

Input Format:

First line  → String A
Second line → String B

Output Format:

Single integer → Minimum edit distance

Sample Input 1:

horse
ros

Sample Output 1:

3

Sample Input 2:

intention
execution

Sample Output 2:

5

❓ Problem 79 — The Tarjan’s SCC Finder

🏷️ Prime | Graph/DFS/SCC | Very Hard

Problem Statement: A telecommunications company has N servers connected by directed links. They want to identify Strongly Connected Components (SCCs) — groups of servers where every server can reach every other server in the group. Use Tarjan’s Algorithm and print each SCC.

Constraints:

1 ≤ N ≤ 1000
Directed graph

Input Format:

First line  → Two integers N E
Next E lines → Two integers U V (directed edge)

Output Format:

Print each SCC on a separate line (nodes space-separated, in any order)

Sample Input 1:

5 5
1 2
2 3
3 1
3 4
4 5

Sample Output 1:

1 2 3
4
5

❓ Problem 80 — The Convex Hull Security Perimeter

🏷️ Prime | Geometry/Convex Hull | Very Hard

Problem Statement: A military base needs to erect a fence around all its watchtowers. Given N watchtower coordinates, find the minimum perimeter fence that encloses all towers — i.e., the Convex Hull of the points. Use Graham Scan or Jarvis March. Print the vertices of the convex hull in counter-clockwise order starting from the bottom-most point, and the perimeter length rounded to 2 decimal places.

Constraints:

3 ≤ N ≤ 10^4
0 ≤ x, y ≤ 10^4

Input Format:

First line  → Integer N
Next N lines → Two integers x y (coordinates)

Output Format:

First line  → Convex hull vertices (x,y pairs) in CCW order
Second line → "Perimeter: X.XX"

Sample Input 1:

5
0 0
1 1
2 2
0 2
2 0

Sample Output 1:

(0,0) (2,0) (2,2) (0,2)
Perimeter: 8.00

❓ Problem 81 — The Alien Number Theory (Big Modular Exponentiation)

🏷️ Prime | Math/Number Theory | Hard

Problem Statement: A cryptography algorithm requires computing (A^B) mod M where A and B can be extremely large. Brute force is too slow — use fast modular exponentiation (binary exponentiation) to compute it efficiently in O(log B) time.

Constraints:

1 ≤ A ≤ 10^18
1 ≤ B ≤ 10^18
1 ≤ M ≤ 10^9

Input Format:

Three integers on separate lines: A, B, M

Output Format:

Single integer → (A^B) mod M

Sample Input 1:

2
10
1000

Sample Output 1:

24

Sample Input 2:

3
200
1000000007

Sample Output 2:

884337246

❓ Problem 82 — The Longest Increasing Subsequence with Count

🏷️ Prime | DP | Hard

Problem Statement: A stock analyst is analyzing stock prices over N days. She wants to find both the length of the Longest Increasing Subsequence (LIS) and the number of such subsequences of that length. Print both values. Count modulo 10^9+7.

Constraints:

1 ≤ N ≤ 2000
1 ≤ price[i] ≤ 10^9

Input Format:

First line  → Integer N
Second line → N space-separated integers

Output Format:

First line  → "LIS Length: X"
Second line → "Count: Y"

Sample Input 1:

6
1 3 5 4 7 8

Sample Output 1:

LIS Length: 5
Count: 2

❓ Problem 83 — The Painter’s Partition Problem

🏷️ Prime | Binary Search + Greedy | Hard

Problem Statement: N boards need to be painted. There are K painters. Each painter can paint contiguous boards only. The time taken to paint a board = board length. All painters work simultaneously. Minimize the time taken by the slowest painter (i.e., minimize the maximum sum of any contiguous partition of N boards into K groups).

Constraints:

1 ≤ K ≤ N ≤ 10^4
1 ≤ board[i] ≤ 10^6

Input Format:

First line  → Two integers N K
Second line → N space-separated integers (board lengths)

Output Format:

Single integer → Minimum time (maximum partition sum minimized)

Sample Input 1:

4 2
10 20 30 40

Sample Output 1:

60

Explanation: Optimal partition: [10,20,30] and [40] → max(60,40) = 60 ✅

❓ Problem 84 — The Interval Scheduling Meeting Rooms

🏷️ Prime | Greedy/Sorting | Hard

Problem Statement: A conference centre manager receives N meeting requests. Each meeting has a start and end time. She wants to find the minimum number of meeting rooms required to accommodate all meetings (no two meetings in the same room can overlap).

Constraints:

1 ≤ N ≤ 10^5
0 ≤ start[i] < end[i] ≤ 10^9

Input Format:

First line  → Integer N
Next N lines → Two integers start end

Output Format:

Single integer → Minimum rooms required

Sample Input 1:

4
0 30
5 10
15 20
5 25

Sample Output 1:

3

❓ Problem 85 — The Regular Expression Matcher

🏷️ Prime | DP/String | Very Hard

Problem Statement: Implement a regular expression matcher supporting:

• . → Matches any single character
• * → Matches zero or more of the preceding element

The match must cover the entire input string (not partial). Print "Match" or "No Match".

Constraints:

0 ≤ len(s), len(p) ≤ 1000
s contains lowercase letters
p contains lowercase letters, '.', '*'

Input Format:

First line  → String s (text)
Second line → String p (pattern)

Output Format:

"Match" or "No Match"

Sample Input 1:

aa
a*

Sample Output 1:

Match

Sample Input 2:

ab
.*

Sample Output 2:

Match

Sample Input 3:

aab
c*a*b

Sample Output 3:

Match

❓ Problem 86 — The Minimum Window Substring

🏷️ Prime | Sliding Window | Hard

Problem Statement: A search engine’s highlight feature needs to find the minimum window substring of string S that contains all characters of string T (including duplicates). If no valid window exists, print "".

Constraints:

1 ≤ len(S) ≤ 10^5
1 ≤ len(T) ≤ 10^4

Input Format:

First line  → String S
Second line → String T

Output Format:

Minimum window substring, or "" if not possible

Sample Input 1:

ADOBECODEBANC
ABC

Sample Output 1:

BANC

Sample Input 2:

a
aa

Sample Output 2:

❓ Problem 87 — The Number of Islands (Union-Find)

🏷️ Prime | Union-Find/DFS | Hard

Problem Statement: A geographer is analysing satellite images. A 2D grid contains 1 (land) and 0 (water). An island is a group of 1s connected horizontally or vertically. Count the total number of distinct islands. Use Union-Find (Disjoint Set Union) for maximum efficiency.

Constraints:

1 ≤ N, M ≤ 300
grid[i][j] ∈ {0, 1}

Input Format:

First line  → Two integers N M
Next N lines → M space-separated integers (0 or 1)

Output Format:

Single integer → Number of islands

Sample Input 1:

4 5
1 1 1 1 0
1 1 0 1 0
1 1 0 0 0
0 0 0 0 0

Sample Output 1:

1

Sample Input 2:

4 5
1 1 0 0 0
1 1 0 0 0
0 0 1 0 0
0 0 0 1 1

Sample Output 2:

3

❓ Problem 88 — The Traveling Salesman Problem (Small N)

🏷️ Prime | DP/Bitmask | Very Hard

Problem Statement: A delivery agent starts from city 0 and must visit all N cities exactly once, then return to city 0. Given the distance matrix, find the minimum total travel distance (TSP using Bitmask DP for N ≤ 20).

Constraints:

2 ≤ N ≤ 15
0 ≤ distance[i][j] ≤ 10^4
distance[i][i] = 0

Input Format:

First line  → Integer N
Next N lines → N space-separated integers (distance matrix row i)

Output Format:

Single integer → Minimum tour distance

Sample Input 1:

4
0 10 15 20
10 0 35 25
15 35 0 30
20 25 30 0

Sample Output 1:

80

❓ Problem 89 — The Suffix Array Construction

🏷️ Prime | String/Suffix Array | Very Hard

Problem Statement: A bioinformatics tool indexes DNA sequences using a Suffix Array — an array of the starting indices of all suffixes of a string, sorted in lexicographic order. Given a DNA string S, construct and output its suffix array.

Constraints:

1 ≤ len(S) ≤ 10^5
String contains only A, C, G, T

Input Format:

Single line → DNA string S

Output Format:

Space-separated integers → Suffix array (starting indices 0-indexed)

Sample Input 1:

ACGT

Sample Output 1:

0 1 2 3

Sample Input 2:

banana

Sample Output 2:

5 3 1 0 4 2

❓ Problem 90 — The Count of Inversions (Merge Sort)

🏷️ Prime | Divide & Conquer | Hard

Problem Statement: A stock market analyst counts inversions in a price array — a pair (i, j) where i < j but arr[i] > arr[j] represents a bad trend. Count the total number of inversions using modified Merge Sort in O(n log n).

Constraints:

1 ≤ N ≤ 10^5
1 ≤ arr[i] ≤ 10^9

Input Format:

First line  → Integer N
Second line → N space-separated integers

Output Format:

Single integer → Number of inversions

Sample Input 1:

5
2 4 1 3 5

Sample Output 1:

3

Explanation: Inversions: (2,1), (4,1), (4,3) → 3 ✅

❓ Problem 91 — The Skip List Implementation

🏷️ Prime | Advanced Data Structure | Very Hard

Problem Statement: A database system uses a Skip List for fast search, insert, and delete. Implement a Skip List and simulate Q operations:

• INSERT x → Insert value x
• DELETE x → Delete value x (if exists)
• SEARCH x → Print "Found" or "Not Found"
• PRINT → Print all elements in sorted order

Constraints:

1 ≤ Q ≤ 10^4
1 ≤ x ≤ 10^6

Input Format:

First line  → Integer Q
Next Q lines → Operation and value

Output Format:

Output for SEARCH and PRINT operations

Sample Input 1:

6
INSERT 5
INSERT 3
INSERT 7
SEARCH 3
DELETE 3
PRINT

Sample Output 1:

Found
5 7

❓ Problem 92 — The Game Theory Nim Problem

🏷️ Prime | Game Theory | Hard

Problem Statement: Two players play Nim: there are N piles of stones. Players take turns. On each turn a player removes any positive number of stones from exactly one pile. The player who takes the last stone wins. Both players play optimally.

Given the pile sizes, determine who wins: “First Player Wins” or “Second Player Wins”.

The optimal strategy uses XOR: if XOR of all pile sizes ≠ 0, first player wins.

Constraints:

1 ≤ N ≤ 100
0 ≤ pile[i] ≤ 10^9

Input Format:

First line  → Integer N
Second line → N space-separated pile sizes

Output Format:

"First Player Wins" or "Second Player Wins"

Sample Input 1:

3
3 4 5

Sample Output 1:

First Player Wins

Sample Input 2:

3
1 2 3

Sample Output 2:

Second Player Wins

Explanation: XOR(3,4,5) = 2 ≠ 0 → First wins. XOR(1,2,3) = 0 → Second wins.

❓ Problem 93 — The Shortest Superstring

🏷️ Prime | DP/Greedy | Very Hard

Problem Statement: A DNA sequencing lab receives N DNA fragments. They want to reconstruct the shortest possible DNA strand that contains all fragments as substrings. This is the Shortest Superstring Problem. For small N (≤ 12), use Bitmask DP. Return the minimum length of such a superstring.

Constraints:

1 ≤ N ≤ 12
1 ≤ len(each fragment) ≤ 50

Input Format:

First line  → Integer N
Next N lines → DNA fragments

Output Format:

Single integer → Minimum superstring length

Sample Input 1:

3
abcd
cdef
efgh

Sample Output 1:

8

Explanation: Superstring: abcdefgh length 8 (cd overlaps, ef overlaps) ✅

❓ Problem 94 — The Segment Overlap Merge

🏷️ Prime | Sorting/Intervals | Hard

Problem Statement: A video editing software has N timeline clips, each represented as an interval [start, end]. The software needs to merge all overlapping clips into the minimum number of non-overlapping intervals. Two intervals overlap if one starts before the other ends (or they touch at a boundary).

Constraints:

1 ≤ N ≤ 10^4
0 ≤ start ≤ end ≤ 10^4

Input Format:

First line  → Integer N
Next N lines → Two integers start end

Output Format:

Merged intervals, one per line: "start end"

Sample Input 1:

5
1 3
2 6
8 10
15 18
9 12

Sample Output 1:

1 6
8 12
15 18

❓ Problem 95 — The K-th Smallest in Matrix

🏷️ Prime | Binary Search/Heap | Hard

Problem Statement: A satellite imaging system stores data in an N×N matrix where each row and column is sorted in ascending order. Given K, find the K-th smallest element in the matrix.

Constraints:

1 ≤ N ≤ 300
1 ≤ K ≤ N²
-10^9 ≤ matrix[i][j] ≤ 10^9

Input Format:

First line  → Two integers N K
Next N lines → N space-separated integers per row

Output Format:

Single integer → K-th smallest element

Sample Input 1:

3 8
1 5 9
10 11 13
12 13 15

Sample Output 1:

13

❓ Problem 96 — The 2-SAT Boolean Satisfiability

🏷️ Prime | Graph/SCC | Very Hard

Problem Statement: A circuit designer has N boolean variables and M clauses, each of the form (xi OR xj) or (xi OR ¬xj) or (¬xi OR ¬xj). This is the 2-SAT Problem. Determine if there exists a valid assignment of True/False to all variables that satisfies all clauses. If yes, print "Satisfiable" and a valid assignment; else "Unsatisfiable". Solve using SCC + Topological Sort.

Constraints:

1 ≤ N ≤ 10^4
1 ≤ M ≤ 10^5

Input Format:

First line  → Two integers N M
Next M lines → Two integers i j
(positive = xi, negative = ¬xi)

Output Format:

"Satisfiable" + assignment on next line, or "Unsatisfiable"

Sample Input 1:

2 3
1 2
-1 2
1 -2

Sample Output 1:

Satisfiable
x1=True x2=True

❓ Problem 97 — The Heavy-Light Decomposition

🏷️ Prime | Tree/HLD | Very Hard

Problem Statement: A power grid is modelled as a tree of N nodes (power stations). Maintenance engineers make two types of queries repeatedly:

1. UPDATE u v x → Add x to all nodes on the path from u to v
2. QUERY u v → Find the maximum node value on the path from u to v

Use Heavy-Light Decomposition + Segment Tree for O(log² n) per query.

Constraints:

1 ≤ N ≤ 10^5
1 ≤ Q ≤ 10^5
1 ≤ initial_value ≤ 10^6

Input Format:

First line  → Two integers N Q
Second line → N initial node values
Next (N-1) lines → Edges of the tree
Next Q lines → "UPDATE u v x" or "QUERY u v"

Output Format:

Answer for each QUERY on a new line

Sample Input 1:

5 3
1 2 3 4 5
1 2
1 3
2 4
2 5
QUERY 4 5
UPDATE 1 3 10
QUERY 1 3

Sample Output 1:

5
13

❓ Problem 98 — The Persistent Segment Tree

🏷️ Prime | Persistent DS | Very Hard

Problem Statement: A version-controlled database needs to answer historical range minimum queries. The database has N initial values and supports:

• UPDATE v i x → Create version v from version (v-1) by updating index i to x
• QUERY v l r → In version v, find the minimum value in range [l, r]

Use a Persistent Segment Tree to store all versions efficiently.

Constraints:

1 ≤ N ≤ 10^5
1 ≤ Q ≤ 10^4

Input Format:

First line  → Two integers N Q
Second line → N initial values (version 0)
Next Q lines → "UPDATE i x" or "QUERY v l r"

Output Format:

Answer for each QUERY on a new line

Sample Input 1:

4 4
1 3 5 7
QUERY 0 1 4
UPDATE 2 10
QUERY 0 1 4
QUERY 1 1 4

Sample Output 1:

1
1
3

❓ Problem 99 — The Polynomial Multiplication via FFT

🏷️ Prime | FFT/Math | Very Hard

Problem Statement: A signal processing system needs to multiply two large polynomials. Given polynomial A of degree N and polynomial B of degree M (both given as coefficient arrays), compute A × B using the Fast Fourier Transform (FFT) in O((N+M) log(N+M)). Print the coefficients of the resulting polynomial from degree 0 to degree N+M.

Constraints:

1 ≤ N, M ≤ 10^5
0 ≤ coefficient ≤ 100

Input Format:

First line  → Integer N (degree of A)
Second line → (N+1) space-separated integers (coefficients of A, from degree 0)
Third line  → Integer M (degree of B)
Fourth line → (M+1) space-separated integers (coefficients of B)

Output Format:

(N+M+1) space-separated integers → Coefficients of A×B

Sample Input 1:

2
1 2 1
2
1 1 1

Sample Output 1:

1 3 4 3 1

Explanation: (1 + 2x + x²)(1 + x + x²) = 1 + 3x + 4x² + 3x³ + x⁴ ✅

❓ Problem 100 — The Final Boss: Offline LCA + Difference Array on Tree

🏷️ Prime | Tree/LCA/Euler Tour | Very Hard

Problem Statement: A research institute models dependency relationships as a rooted tree (root = node 1) with N nodes. A professor issues Q queries, each of the form (u, v, x): add x to every node on the path from u to v. After all updates, print the final value of each node.

Use:

• Binary Lifting for O(log n) LCA
• Euler Tour + Difference Array on Tree for path updates in O(N + Q log N)

Constraints:

1 ≤ N ≤ 10^5
1 ≤ Q ≤ 10^5
1 ≤ x ≤ 10^4

Input Format:

First line  → Two integers N Q
Next (N-1) lines → Edges of the tree (undirected)
Next Q lines → Three integers u v x

Output Format:

N space-separated integers → Final value of each node (1 to N)

Sample Input 1:

5 2
1 2
1 3
2 4
2 5
1 4 5
3 5 3

Sample Output 1:

8 8 3 5 8

Explanation: Path 1→4: nodes {1,2,4} += 5. Path 3→5: nodes {3,1,2,5} += 3. Final: node1=8, node2=8, node3=3, node4=5, node5=8 ✅

COMPLETE 100-QUESTION MASTER TABLE

100 ACTUAL TCS VERBAL ABILITY QUESTIONS (2020-2025) TCS NQT | TCS Smart Hiring | TCS Ignite – Previous Year Questions

One Shot Last Minute TCS Smart & NQT Verbal | 100% Repeating | Beat the Timer Challenge

SECTION A: READING COMPREHENSION (20 Questions)

PASSAGE 1 (Questions 1-4) – TCS NQT 2024

Passage: Artificial Intelligence has transformed the technology landscape in unprecedented ways. Machine learning algorithms now power everything from recommendation systems to autonomous vehicles. However, concerns about job displacement and ethical implications remain significant. While AI can automate repetitive tasks, it also creates new opportunities in data science, AI ethics, and human-AI interaction design. The future likely holds a collaborative model where humans and AI work together rather than compete.

Q1. What is the main theme of the passage?

• a) AI will replace all human jobs
• b) AI’s transformative impact with both challenges and opportunities ✓
• c) Machine learning is the only important technology
• d) Ethical concerns make AI dangerous

Q2. According to the passage, what does AI currently power?

• a) Only autonomous vehicles
• b) Recommendation systems and autonomous vehicles ✓
• c) Only recommendation systems
• d) All industrial processes

Q3. What does the passage suggest about future human-AI interaction?

• a) Complete competition
• b) Humans will be eliminated
• c) Collaborative model ✓
• d) No interaction

Q4. Which new opportunities does AI create according to the passage?

• a) Manufacturing only
• b) Data science, AI ethics, and human-AI interaction design ✓
• c) Traditional engineering
• d) Manual labor jobs

PASSAGE 2 (Questions 5-8) – TCS Smart Hiring 2024

Passage: Cloud computing has revolutionized how businesses manage their IT infrastructure. Instead of maintaining expensive on-premises servers, companies can now access computing resources on-demand through the internet. This shift has led to significant cost savings, improved scalability, and enhanced disaster recovery capabilities. Major cloud providers like AWS, Azure, and Google Cloud offer various service models including Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Despite these advantages, organizations must carefully consider data security and compliance requirements before migrating to the cloud.

Q5. What is the primary benefit of cloud computing mentioned?

• a) Faster internet
• b) On-demand access to computing resources ✓
• c) Free services
• d) Unlimited storage

Q6. Which service models are mentioned in the passage?

• a) Only IaaS
• b) IaaS, PaaS, and SaaS ✓
• c) Only SaaS
• d) None mentioned

Q7. What must organizations consider before cloud migration?

• a) Cost only
• b) Speed only
• c) Data security and compliance ✓
• d) Employee training only

Q8. The passage suggests cloud computing provides:

• a) Cost savings and scalability ✓
• b) Only security benefits
• c) No real advantages
• d) Complexity

PASSAGE 3 (Questions 9-12) – TCS Ignite 2024

Passage: Sustainable development has become a critical global priority. It refers to meeting present needs without compromising the ability of future generations to meet their own needs. This involves balancing economic growth, environmental protection, and social equity. Companies are increasingly adopting sustainable practices such as reducing carbon emissions, using renewable energy, and implementing circular economy principles. Consumers are also becoming more conscious, preferring brands that demonstrate environmental responsibility. Governments worldwide are setting ambitious targets for carbon neutrality, typically aiming for 2050 or earlier.

Q9. What does sustainable development mean according to the passage?

• a) Only economic growth
• b) Meeting present needs without compromising future generations ✓
• c) Environmental protection only
• d) Social equity only

Q10. What are companies doing to be sustainable?

• a) Ignoring environmental concerns
• b) Reducing emissions, using renewable energy, circular economy ✓
• c) Increasing pollution
• d) Focusing only on profits

Q11. What is the typical carbon neutrality target year mentioned?

• a) 2030
• b) 2040
• c) 2050 ✓
• d) 2100

Q12. According to the passage, what are consumers doing?

• a) Ignoring sustainability
• b) Preferring environmentally responsible brands ✓
• c) Buying only cheap products
• d) Not caring about the environment

PASSAGE 4 (Questions 13-16) – TCS NQT 2023

Passage: The COVID-19 pandemic accelerated the adoption of remote work globally. Organizations quickly implemented work-from-home policies, discovering that productivity could be maintained or even improved with proper tools and management. Video conferencing platforms like Zoom and Microsoft Teams became essential. However, challenges emerged including work-life balance issues, mental health concerns, and difficulties in team collaboration. Many companies are now adopting hybrid models, combining remote and office work to leverage benefits of both approaches.

Q13. What did the pandemic accelerate?

• a) Office construction
• b) Remote work adoption ✓
• c) Manufacturing
• d) Traditional business

Q14. What did organizations discover about remote work?

• a) It reduces productivity
• b) Productivity could be maintained or improved ✓
• c) It’s impossible
• d) It’s only temporary

Q15. What challenges are mentioned?

• a) Technical issues only
• b) Work-life balance, mental health, team collaboration ✓
• c) Only internet problems
• d) No challenges mentioned

Q16. What approach are companies now adopting?

• a) Full office work
• b) Full remote work
• c) Hybrid models ✓
• d) No work

PASSAGE 5 (Questions 17-20) – TCS Smart Hiring 2023

Passage: Blockchain technology extends far beyond cryptocurrencies. This distributed ledger technology offers transparency, security, and immutability, making it valuable for supply chain management, healthcare records, voting systems, and digital identity verification. Smart contracts—self-executing contracts with terms directly written into code—automate processes and reduce intermediary costs. While blockchain holds immense promise, challenges include scalability, energy consumption, and regulatory uncertainty. As the technology matures, we can expect wider adoption across industries.

Q17. What is blockchain technology primarily known for?

• a) Only cryptocurrencies
• b) Distributed ledger with transparency and security ✓
• c) Social media
• d) Gaming

Q18. What are smart contracts?

• a) Legal documents
• b) Self-executing contracts in code ✓
• c) Paper contracts
• d) Voice agreements

Q19. Which applications are mentioned for blockchain?

• a) Only finance
• b) Supply chain, healthcare, voting, digital identity ✓
• c) Only healthcare
• d) Social networking

Q20. What challenges does blockchain face?

• a) No challenges
• b) Scalability, energy consumption, regulatory uncertainty ✓
• c) Only cost issues
• d) User adoption only

SECTION B: VOCABULARY (20 Questions)

SYNONYMS (10 Questions)

Q21. TCS NQT 2024 | Synonym of UBIQUITOUS:

• a) Rare
• b) Present everywhere ✓
• c) Ancient
• d) Specific

Q22. TCS Smart Hiring 2024 | Synonym of MITIGATE:

• a) Aggravate
• b) Reduce ✓
• c) Increase
• d) Ignore

Q23. TCS NQT 2024 | Synonym of PRAGMATIC:

• a) Impractical
• b) Theoretical
• c) Practical ✓
• d) Idealistic

Q24. TCS Ignite 2024 | Synonym of COHERENT:

• a) Confusing
• b) Logical ✓
• c) Scattered
• d) Random

Q25. TCS NQT 2023 | Synonym of METICULOUS:

• a) Careless
• b) Careful ✓
• c) Quick
• d) Lazy

Q26. TCS Smart Hiring 2023 | Synonym of AMBIGUOUS:

• a) Clear
• b) Uncertain ✓
• c) Obvious
• d) Simple

Q27. TCS NQT 2024 | Synonym of RESILIENT:

• a) Fragile
• b) Strong ✓
• c) Weak
• d) Brittle

Q28. TCS Ignite 2024 | Synonym of COMPREHENSIVE:

• a) Incomplete
• b) Thorough ✓
• c) Partial
• d) Limited

Q29. TCS NQT 2023 | Synonym of PROFICIENT:

• a) Inexperienced
• b) Skilled ✓
• c) Amateur
• d) Beginner

Q30. TCS Smart Hiring 2024 | Synonym of OBSOLETE:

• a) Modern
• b) Outdated ✓
• c) Current
• d) New

ANTONYMS (10 Questions)

Q31. TCS NQT 2024 | Antonym of CONCISE:

• a) Brief
• b) Short
• c) Verbose ✓
• d) Clear

Q32. TCS Smart Hiring 2024 | Antonym of BENEVOLENT:

• a) Kind
• b) Generous
• c) Malevolent ✓
• d) Helpful

Q33. TCS Ignite 2024 | Antonym of PLAUSIBLE:

• a) Believable
• b) Reasonable
• c) Implausible ✓
• d) Logical

Q34. TCS NQT 2023 | Antonym of OPAQUE:

• a) Dark
• b) Transparent ✓
• c) Thick
• d) Heavy

Q35. TCS Smart Hiring 2023 | Antonym of VOLATILE:

• a) Unstable
• b) Stable ✓
• c) Explosive
• d) Dangerous

Q36. TCS NQT 2024 | Antonym of ABUNDANCE:

• a) Plenty
• b) Surplus
• c) Scarcity ✓
• d) Wealth

Q37. TCS Ignite 2024 | Antonym of OPTIMISTIC:

• a) Hopeful
• b) Positive
• c) Pessimistic ✓
• d) Cheerful

Q38. TCS NQT 2023 | Antonym of MANDATORY:

• a) Required
• b) Compulsory
• c) Optional ✓
• d) Necessary

Q39. TCS Smart Hiring 2024 | Antonym of EXPAND:

• a) Grow
• b) Enlarge
• c) Contract ✓
• d) Stretch

Q40. TCS NQT 2024 | Antonym of GENUINE:

• a) Real
• b) Authentic
• c) Fake ✓
• d) True

SECTION C: GRAMMAR (20 Questions)

ERROR SPOTTING (10 Questions)

Q41. TCS NQT 2024 “Neither of the candidates have submitted their documents on time.”

• a) Neither of
• b) have submitted ✓ (should be “has”)
• c) their documents
• d) No error

Q42. TCS Smart Hiring 2024 “The data was presented in a comprehensive manner.”

• a) The data
• b) was presented
• c) comprehensive
• d) No error ✓

Q43. TCS Ignite 2024 “Each of the students have their own laptop.”

• a) Each of
• b) have ✓ (should be “has”)
• c) their own
• d) No error

Q44. TCS NQT 2023 “Between you and I, this is confidential.”

• a) Between
• b) you and I ✓ (should be “you and me”)
• c) this is
• d) No error

Q45. TCS Smart Hiring 2023 “One of my friends are going abroad for studies.”

• a) One of
• b) are going ✓ (should be “is going”)
• c) for studies
• d) No error

Q46. TCS NQT 2024 “The team have won the championship.”

• a) The team
• b) have won ✓ (should be “has won”)
• c) the championship
• d) No error

Q47. TCS Ignite 2024 “He is one of those people who is always late.”

• a) He is
• b) those people
• c) who is ✓ (should be “who are”)
• d) No error

Q48. TCS NQT 2023 “Neither the manager nor the employees was aware of the policy.”

• a) Neither
• b) nor
• c) was aware ✓ (should be “were aware”)
• d) No error

Q49. TCS Smart Hiring 2024 “She insisted on going to the meeting despite being unwell.”

• a) insisted on
• b) going to
• c) despite being
• d) No error ✓

Q50. TCS NQT 2024 “The number of employees have increased significantly.”

• a) The number
• b) have increased ✓ (should be “has increased”)
• c) significantly
• d) No error

SENTENCE CORRECTION (10 Questions)

Q51. TCS NQT 2024 Choose the correct sentence:

• a) He don’t know the answer
• b) He doesn’t know the answer ✓
• c) He didn’t knew the answer
• d) He not know the answer

Q52. TCS Smart Hiring 2024 Choose the correct sentence:

• a) I have went to the market
• b) I have go to the market
• c) I have gone to the market ✓
• d) I has gone to the market

Q53. TCS Ignite 2024 Choose the correct sentence:

• a) She is senior than me
• b) She is senior to me ✓
• c) She is senior from me
• d) She is senior of me

Q54. TCS NQT 2023 Choose the correct sentence:

• a) If I was you, I would accept
• b) If I were you, I would accept ✓
• c) If I am you, I would accept
• d) If I be you, I would accept

Q55. TCS Smart Hiring 2023 Choose the correct sentence:

• a) The book is laying on the table
• b) The book is lying on the table ✓
• c) The book is laid on the table
• d) The book is lay on the table

Q56. TCS NQT 2024 Choose the correct sentence:

• a) Me and John completed the task
• b) John and I completed the task ✓
• c) I and John completed the task
• d) John and me completed the task

Q57. TCS Ignite 2024 Choose the correct sentence:

• a) She has been living here since 2015 ✓
• b) She has been living here from 2015
• c) She has been living here for 2015
• d) She is living here since 2015

Q58. TCS NQT 2023 Choose the correct sentence:

• a) By the time you arrive, I will complete the work
• b) By the time you arrive, I will have completed the work ✓
• c) By the time you arrive, I complete the work
• d) By the time you arrive, I completed the work

Q59. TCS Smart Hiring 2024 Choose the correct sentence:

• a) The meeting has been postponed to next Monday ✓
• b) The meeting has been postponed till next Monday
• c) The meeting has been postponed by next Monday
• d) The meeting has been postponed on next Monday

Q60. TCS NQT 2024 Choose the correct sentence:

• a) Neither of them are available
• b) Neither of them is available ✓
• c) Neither of them were available
• d) Neither of them have available

SECTION D: SENTENCE COMPLETION (15 Questions)

Q61. TCS NQT 2024 The project manager _____ the team’s efforts during the meeting.

• a) criticized
• b) appreciated ✓
• c) ignored
• d) questioned

Q62. TCS Smart Hiring 2024 Despite facing numerous challenges, the team _____ to deliver on time.

• a) failed
• b) managed ✓
• c) refused
• d) hesitated

Q63. TCS Ignite 2024 The new policy will _____ effect from next month.

• a) take ✓
• b) make
• c) give
• d) bring

Q64. TCS NQT 2023 She has a _____ for learning new programming languages quickly.

• a) hatred
• b) knack ✓
• c) dislike
• d) problem

Q65. TCS Smart Hiring 2023 The CEO’s decision was met with _____ from shareholders.

• a) indifference
• b) approval ✓
• c) hostility
• d) confusion

Q66. TCS NQT 2024 The company aims to _____ its market share by 20%.

• a) decrease
• b) maintain
• c) increase ✓
• d) eliminate

Q67. TCS Ignite 2024 His _____ approach to problem-solving impressed everyone.

• a) careless
• b) innovative ✓
• c) traditional
• d) slow

Q68. TCS NQT 2023 The software _____ several bugs that need fixing.

• a) creates
• b) contains ✓
• c) removes
• d) ignores

Q69. TCS Smart Hiring 2024 The presentation was _____ and well-structured.

• a) confusing
• b) comprehensive ✓
• c) incomplete
• d) brief

Q70. TCS NQT 2024 The deadline has been _____ by two weeks.

• a) shortened
• b) extended ✓
• c) cancelled
• d) ignored

Q71. TCS Ignite 2024 The consultant provided _____ insights into the problem.

• a) superficial
• b) valuable ✓
• c) irrelevant
• d) confusing

Q72. TCS NQT 2023 The team worked _____ to meet the tight deadline.

• a) slowly
• b) diligently ✓
• c) carelessly
• d) reluctantly

Q73. TCS Smart Hiring 2024 The new framework will _____ development time significantly.

• a) increase
• b) reduce ✓
• c) maintain
• d) complicate

Q74. TCS NQT 2024 Her _____ in handling complex situations is commendable.

• a) incompetence
• b) expertise ✓
• c) inexperience
• d) hesitation

Q75. TCS Ignite 2024 The proposal was _____ by the board of directors.

• a) rejected
• b) approved ✓
• c) ignored
• d) delayed

SECTION E: PARA JUMBLES (10 Questions)

Q76. TCS NQT 2024 Arrange the sentences in proper order: A) The project was delayed B) Due to technical issues C) However, it was completed D) Within the extended deadline

• a) ABCD ✓
• b) ACBD
• c) BACD
• d) CDAB

Q77. TCS Smart Hiring 2024 Arrange the sentences: A) Machine learning is transforming B) Various industries today C) From healthcare to finance D) With unprecedented efficiency

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q78. TCS Ignite 2024 Arrange the sentences: A) Data security is paramount B) In today’s digital age C) Organizations must implement D) Robust cybersecurity measures

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q79. TCS NQT 2023 Arrange the sentences: A) The software development lifecycle B) Includes several phases C) From requirements gathering D) To deployment and maintenance

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q80. TCS Smart Hiring 2023 Arrange the sentences: A) Agile methodology emphasizes B) Iterative development C) And continuous feedback D) Throughout the project lifecycle

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q81. TCS NQT 2024 Arrange the sentences: A) Artificial intelligence B) Is revolutionizing C) The way we work D) And solve problems

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q82. TCS Ignite 2024 Arrange the sentences: A) Cloud computing offers B) Scalable solutions C) For modern businesses D) With cost-effective infrastructure

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q83. TCS NQT 2023 Arrange the sentences: A) Digital transformation B) Requires strategic planning C) And effective implementation D) Across the organization

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q84. TCS Smart Hiring 2024 Arrange the sentences: A) Cybersecurity threats B) Are becoming more sophisticated C) Requiring advanced defense D) Mechanisms and protocols

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

Q85. TCS NQT 2024 Arrange the sentences: A) Remote work B) Has become mainstream C) Changing traditional D) Office dynamics permanently

• a) ABCD ✓
• b) BACD
• c) CDAB
• d) DACB

SECTION F: PREPOSITIONS & IDIOMS (15 Questions)

PREPOSITIONS (8 Questions)

Q86. TCS NQT 2024 Fill in the blank: “The solution _____ the problem is simple.”

• a) of
• b) to ✓
• c) for
• d) with

Q87. TCS Smart Hiring 2024 “He is good _____ mathematics.”

• a) in
• b) at ✓
• c) on
• d) with

Q88. TCS Ignite 2024 “She is senior _____ me in the organization.”

• a) than
• b) to ✓
• c) from
• d) of

Q89. TCS NQT 2023 “The meeting has been scheduled _____ 3 PM.”

• a) in
• b) on
• c) at ✓
• d) for

Q90. TCS Smart Hiring 2023 “She succeeded _____ her efforts.”

• a) by
• b) through ✓
• c) with
• d) from

Q91. TCS NQT 2024 “He is afraid _____ failure.”

• a) from
• b) of ✓
• c) with
• d) by

Q92. TCS Ignite 2024 “The book is available _____ the library.”

• a) at ✓
• b) on
• c) in
• d) to

Q93. TCS NQT 2023 “She is engaged _____ writing a novel.”

• a) at
• b) in ✓
• c) on
• d) with

IDIOMS & PHRASES (7 Questions)

Q94. TCS NQT 2024 “To beat around the bush” means:

• a) To hit plants
• b) To avoid the main topic ✓
• c) To be direct
• d) To be honest

Q95. TCS Smart Hiring 2024 “A piece of cake” means:

• a) A dessert
• b) Very difficult
• c) Very easy ✓
• d) Expensive

Q96. TCS Ignite 2024 “To spill the beans” means:

• a) To cook food
• b) To reveal a secret ✓
• c) To waste food
• d) To organize

Q97. TCS NQT 2023 “Once in a blue moon” means:

• a) Every night
• b) Very rarely ✓
• c) Very often
• d) Never

Q98. TCS Smart Hiring 2023 “To break the ice” means:

• a) To start a conversation ✓
• b) To end a relationship
• c) To be cold
• d) To destroy something

Q99. TCS NQT 2024 “To cut corners” means:

• a) To take shortcuts ✓
• b) To be thorough
• c) To be careful
• d) To be precise

Q100. TCS Ignite 2024 “To hit the nail on the head” means:

• a) To be exactly right ✓
• b) To make a mistake
• c) To be violent
• d) To build something

TOPIC-WISE DISTRIBUTION

One Shot Last Minute TCS Smart & NQT Verbal | 100% Repeating | Beat the Timer Challenge

50 DELOITTE ACTUAL CODING QUESTIONS (2020-2025)

QUESTION 1: Even Sum Pair Formation ⭐⭐⭐

Difficulty: Medium | Frequency: 95% | Year: 2024-2025

Problem Statement: Given an array of N integers, determine whether it’s possible to divide all numbers into pairs such that the sum of each pair is even. Every element must be paired exactly once. Print “YES” if possible, otherwise “NO”.

Input Format:

First line: N (number of elements)
Second line: N space-separated integers

Output Format:

YES or NO

Sample Input:

6
2 3 4 5 6 7

Sample Output:

YES

QUESTION 2: Binary Virus (Bit Manipulation) ⭐⭐⭐

Difficulty: Easy-Medium | Frequency: 98% | Year: 2023-2025

Problem Statement: Every decimal number can be converted to binary. Your computer has a “Corona Virus” that eats binary digits from the right side (LSB – Least Significant Bits). If the virus has ‘k’ spikes, it will eat ‘k’ LSB binary digits from your numbers.

Given an array of N numbers and spike count k, calculate the final values after the virus attack.

Input Format:

First line: N (size of array)
Second line: N space-separated integers
Third line: k (number of spikes/bits to remove)

Output Format:

N space-separated integers (final values)

Sample Input:

3
8 15 20
2

Sample Output:

2 3 5

QUESTION 3: Linked List Momentum Calculation ⭐⭐

Difficulty: Easy | Frequency: 92% | Year: 2024-2025

Problem Statement: Ratul made a linked list of N nodes where each node has two variables: the velocity and the mass of a particle. Since all particles have velocity in the same direction, find the total momentum of the entity made by the particles from the linked list.

Formula: Momentum = mass × velocity

Input Format:

First line: n (number of nodes)
Next n lines: mass velocity (space-separated)

Output Format:

Single integer denoting total momentum

Sample Input:

4
1 3
2 4
2 3
4 5

Sample Output:

37

QUESTION 4: Minimum String Deletions (Palindrome) ⭐⭐⭐

Difficulty: Medium | Frequency: 85% | Year: 2024-2025

Problem Statement: Given a string, find the minimum number of character deletions required to make it a non-palindrome. If the string is already a non-palindrome, return 0. If it’s impossible to make it non-palindrome (all characters are same), return -1.

Input Format:

Single string S

Output Format:

Single integer (minimum deletions)

Sample Input 1:

aabaa

Sample Output 1:

1

Sample Input 2:

aaaa

Sample Output 2:

-1

Sample Input 3:

abc

Sample Output 3:

0

QUESTION 5: Second Largest Element ⭐⭐

Difficulty: Easy | Frequency: 90% | Year: 2023-2025

Problem Statement: Find the second largest element in an array without using sorting. If second largest doesn’t exist, print -1.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

Single integer (second largest element or -1)

Sample Input:

6
12 35 1 10 34 1

Sample Output:

34

QUESTION 6: Move All Zeros to End ⭐⭐

Difficulty: Easy | Frequency: 88% | Year: 2023-2025

Problem Statement: Move all zeros to the end of array while maintaining the relative order of non-zero elements.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

Modified array with zeros at end

Sample Input:

5
0 1 0 3 12

Sample Output:

1 3 12 0 0

QUESTION 7: Anagram Check ⭐⭐

Difficulty: Easy | Frequency: 92% | Year: 2023-2025

Problem Statement: Check if two strings are anagrams of each other. Two strings are anagrams if they contain the same characters with the same frequency.

Input Format:

Two lines with two strings

Output Format:

1 if anagram, 0 if not

Sample Input:

listen
silent

Sample Output:

1

QUESTION 8: First Non-Repeating Character ⭐⭐

Difficulty: Easy-Medium | Frequency: 84% | Year: 2024-2025

Problem Statement: Find the first non-repeating character in a string. If no such character exists, return -1.

Input Format:

Single string

Output Format:

First non-repeating character or -1

Sample Input:

programming

Sample Output:

p

QUESTION 9: Leaders in Array ⭐⭐⭐

Difficulty: Medium | Frequency: 78% | Year: 2023-2024

Problem Statement: An element is a leader if it is greater than all elements to its right. The rightmost element is always a leader. Find all leaders in the array and print them in the order they appear.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

All leaders space-separated

Sample Input:

6
16 17 4 3 5 2

Sample Output:

17 5 2

QUESTION 10: Digital Root (Sum Until Single Digit) ⭐⭐

Difficulty: Easy | Frequency: 80% | Year: 2023-2024

Problem Statement: Given a number, keep adding its digits until you get a single digit. This is called the digital root.

Input Format:

Single integer N

Output Format:

Single digit result

Sample Input:

9875

Sample Output:

2

Explanation:

9 + 8 + 7 + 5 = 29
2 + 9 = 11
1 + 1 = 2

QUESTION 11: Sum of Even Numbers in Array ⭐

Difficulty: Very Easy | Frequency: 75% | Year: 2024

Problem Statement: Calculate the sum of all even numbers in the given array.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

Single integer (sum of even numbers)

Sample Input:

5
1 2 3 4 5

Sample Output:

6

QUESTION 12: Count Subarrays with Odd Sum ⭐⭐⭐

Difficulty: Medium | Frequency: 72% | Year: 2024

Problem Statement: Count the number of subarrays where the sum of elements is odd.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

Single integer (count of subarrays)

Sample Input:

4
1 2 3 4

Sample Output:

6

QUESTION 13: Reverse Words in String ⭐⭐

Difficulty: Easy | Frequency: 86% | Year: 2023-2024

Problem Statement: Reverse the order of words in a given string while maintaining the word order intact.

Input Format:

Single string with words separated by spaces

Output Format:

String with reversed word order

Sample Input:

Welcome to Deloitte

Sample Output:

Deloitte to Welcome

QUESTION 14: Check Prime Number ⭐

Difficulty: Very Easy | Frequency: 82% | Year: 2023-2024

Problem Statement: Check if a given number is prime or not.

Input Format:

Single integer N

Output Format:

"Prime" or "Not Prime"

Sample Input:

17

Sample Output:

Prime

QUESTION 15: Fibonacci Series ⭐

Difficulty: Easy | Frequency: 88% | Year: 2023-2024

Problem Statement: Print the first N Fibonacci numbers.

Input Format:

Single integer N

Output Format:

N space-separated Fibonacci numbers

Sample Input:

7

Sample Output:

0 1 1 2 3 5 8

QUESTION 16: Armstrong Number Check ⭐⭐

Difficulty: Easy | Frequency: 76% | Year: 2023-2024

Problem Statement: Check if a given number is an Armstrong number. An Armstrong number is a number that is equal to the sum of its own digits raised to the power of the number of digits.

Input Format:

Single integer N

Output Format:

"Armstrong Number" or "Not Armstrong Number"

Sample Input:

153

Sample Output:

Armstrong Number

Explanation:

153 = 1³ + 5³ + 3³ = 1 + 125 + 27 = 153

QUESTION 17: GCD of Two Numbers ⭐⭐

Difficulty: Easy | Frequency: 70% | Year: 2023-2024

Problem Statement: Find the Greatest Common Divisor (GCD) of two numbers.

Input Format:

Two space-separated integers

Output Format:

Single integer (GCD)

Sample Input:

36 60

Sample Output:

12

QUESTION 18: LCM of Two Numbers ⭐⭐

Difficulty: Easy | Frequency: 68% | Year: 2023-2024

Problem Statement: Find the Least Common Multiple (LCM) of two numbers.

Input Format:

Two space-separated integers

Output Format:

Single integer (LCM)

Sample Input:

4 6

Sample Output:

12

QUESTION 19: Factorial of Number ⭐

Difficulty: Very Easy | Frequency: 84% | Year: 2023-2024

Problem Statement: Calculate the factorial of a given number N.

Input Format:

Single integer N

Output Format:

Single integer (factorial of N)

Sample Input:

5

Sample Output:

120

QUESTION 20: Remove Duplicates from Sorted Array ⭐⭐

Difficulty: Easy | Frequency: 74% | Year: 2024

Problem Statement: Remove duplicates from a sorted array and print the unique elements.

Input Format:

First line: N (size of array)
Second line: N space-separated integers (sorted)

Output Format:

Unique elements space-separated

Sample Input:

7
1 1 2 2 3 4 4

Sample Output:

1 2 3 4

QUESTION 21: Find Missing Number (1 to N) ⭐⭐

Difficulty: Easy | Frequency: 80% | Year: 2024

Problem Statement: An array contains N-1 numbers taken from the range 1 to N. Find the missing number.

Input Format:

First line: N
Second line: N-1 space-separated integers

Output Format:

Single integer (missing number)

Sample Input:

5
1 2 4 5

Sample Output:

3

QUESTION 22: Count Set Bits ⭐⭐

Difficulty: Easy-Medium | Frequency: 65% | Year: 2024

Problem Statement: Count the number of set bits (1s) in the binary representation of a number.

Input Format:

Single integer N

Output Format:

Single integer (count of set bits)

Sample Input:

7

Sample Output:

3

Explanation:

7 in binary = 111 (three 1s)

QUESTION 23: Power of Two Check ⭐⭐

Difficulty: Easy | Frequency: 72% | Year: 2024

Problem Statement: Check if a given number is a power of 2.

Input Format:

Single integer N

Output Format:

"Yes" or "No"

Sample Input:

16

Sample Output:

Yes

QUESTION 24: Rotate Array by K Positions ⭐⭐⭐

Difficulty: Medium | Frequency: 68% | Year: 2024

Problem Statement: Rotate an array to the right by K positions.

Input Format:

First line: N (size of array)
Second line: N space-separated integers
Third line: K (number of rotations)

Output Format:

Rotated array space-separated

Sample Input:

5
1 2 3 4 5
2

Sample Output:

4 5 1 2 3

QUESTION 25: Maximum Subarray Sum (Kadane’s Algorithm) ⭐⭐⭐

Difficulty: Medium | Frequency: 70% | Year: 2024

Problem Statement: Find the contiguous subarray with the maximum sum.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

Single integer (maximum sum)

Sample Input:

9
-2 1 -3 4 -1 2 1 -5 4

Sample Output:

6

Explanation:

Subarray [4, -1, 2, 1] has maximum sum = 6

QUESTION 26: Binary Search Implementation ⭐⭐

Difficulty: Easy-Medium | Frequency: 78% | Year: 2024

Problem Statement: Implement binary search to find the index of a target element in a sorted array. Return -1 if not found.

Input Format:

First line: N (size of array)
Second line: N space-separated integers (sorted)
Third line: target (element to search)

Output Format:

Index of target or -1

Sample Input:

7
2 5 8 12 16 23 38
23

Sample Output:

5

QUESTION 27: Count Frequency of Each Character ⭐⭐

Difficulty: Easy | Frequency: 82% | Year: 2024

Problem Statement: Count the frequency of each character in a string and print in order of appearance.

Input Format:

Single string

Output Format:

character-frequency pairs space-separated

Sample Input:

programming

Sample Output:

p-1 r-2 o-1 g-2 a-1 m-2 i-1 n-1

QUESTION 28: Merge Two Sorted Arrays ⭐⭐

Difficulty: Easy-Medium | Frequency: 74% | Year: 2024

Problem Statement: Merge two sorted arrays into a single sorted array.

Input Format:

First line: N1 (size of first array)
Second line: N1 space-separated integers (sorted)
Third line: N2 (size of second array)
Fourth line: N2 space-separated integers (sorted)

Output Format:

Merged sorted array space-separated

Sample Input:

3
1 3 5
3
2 4 6

Sample Output:

1 2 3 4 5 6

QUESTION 29: Find Equilibrium Index ⭐⭐⭐

Difficulty: Medium | Frequency: 66% | Year: 2024

Problem Statement: Find the equilibrium index where the sum of elements to the left equals the sum of elements to the right.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

Index of equilibrium point or -1

Sample Input:

5
1 3 5 2 2

Sample Output:

2

Explanation:

At index 2: left sum (1+3=4) = right sum (2+2=4)

QUESTION 30: Longest Consecutive Sequence ⭐⭐⭐

Difficulty: Medium | Frequency: 62% | Year: 2024

Problem Statement: Find the length of the longest consecutive sequence in an unsorted array.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

Single integer (length of longest sequence)

Sample Input:

6
100 4 200 1 3 2

Sample Output:

4

Explanation:

Longest consecutive sequence: 1, 2, 3, 4

QUESTION 31: Palindrome Check (Ignore Spaces & Case) ⭐⭐

Difficulty: Easy | Frequency: 88% | Year: 2023-2024

Problem Statement: Check if a given string is a palindrome, ignoring spaces, punctuation, and case.

Input Format:

Single string

Output Format:

"True" or "False"

Sample Input:

A man a plan a canal Panama

Sample Output:

True

QUESTION 32: Remove Vowels from String ⭐

Difficulty: Very Easy | Frequency: 76% | Year: 2024

Problem Statement: Remove all vowels (both uppercase and lowercase) from a string.

Input Format:

Single string

Output Format:

String without vowels

Sample Input:

Deloitte

Sample Output:

Dltt

QUESTION 33: Count Words in String ⭐

Difficulty: Very Easy | Frequency: 80% | Year: 2024

Problem Statement: Count the number of words in a string. Words are separated by spaces.

Input Format:

Single string

Output Format:

Single integer (word count)

Sample Input:

Welcome to Deloitte India

Sample Output:

4

QUESTION 34: Find Duplicate in Array ⭐⭐

Difficulty: Easy-Medium | Frequency: 70% | Year: 2024

Problem Statement: Find the first duplicate element in an array.

Input Format:

First line: N (size of array)
Second line: N space-separated integers

Output Format:

First duplicate element

Sample Input:

5
1 2 3 2 4

Sample Output:

2

QUESTION 35: Sort Array of 0s, 1s, and 2s (Dutch Flag) ⭐⭐⭐

Difficulty: Medium | Frequency: 64% | Year: 2024

Problem Statement: Sort an array containing only 0s, 1s, and 2s without using any sorting algorithm.