Campusmonk DSA BlackBook Series – Part 1 (Exam Pattern)
Q1. Count All Digits of a Number
Problem Statement:
Given an integer n, write a program to count the total number of digits in n.
Input Format:
-
A single integer n (0 ≤ n ≤ 10⁹)
Output Format:
-
An integer representing the number of digits in n
Examples:
Input: 4
Output: 1
Input: 14
Output: 2
✅ Q2. Count Number of Odd Digits
Problem Statement:
Given an integer n, return the number of odd digits present in n.
Input Format:
-
A single integer n
Output Format:
-
An integer representing the number of odd digits
Examples:
Input: 5
Output: 1
Input: 25
Output: 1
✅ Q3. Reverse a Number
Problem Statement:
Given an integer n, return the number formed by reversing its digits.
Ignore any leading zeros in the reversed number.
Input Format:
-
A single integer n
Output Format:
-
Reversed integer
Examples:
Input: 1234
Output: 4321
Input: 120
Output: 21
✅ Q4. Check if a Number is Palindrome
Problem Statement:
Write a program to check whether a given number n is a palindrome.
A number is a palindrome if it reads the same forwards and backwards.
Input Format:
-
A single integer n
Output Format:
-
true if it is a palindrome, otherwise false
Examples:
Input: 121
Output: true
Input: 123
Output: false
✅ Q5. Find the Largest Digit in a Number
Problem Statement:
Given a positive integer n, write a program to find the largest digit in the number.
Input Format:
-
A single integer n
Output Format:
-
An integer representing the largest digit
Examples:
Input: 5492
Output: 9
Input: 103
Output: 3
✅ Q6. Print All Divisors of a Number
Problem Statement:
Given a number n, write a program to print all the divisors of n in ascending order.
Input Format:
-
A single integer n (1 ≤ n ≤ 10⁶)
Output Format:
-
Space-separated integers representing all divisors of n
Examples:
Input: 12
Output: 1 2 3 4 6 12
Input: 7
Output: 1 7
✅ Q7. Factorial of a Number
Problem Statement:
Write a program to find the factorial of a given number n.
Input Format:
-
A single integer n (1 ≤ n ≤ 20)
Output Format:
-
A single long integer representing n!
Examples:
Input: 5
Output: 120
Input: 1
Output: 1
✅ Q8. Check if a Number is Armstrong
Problem Statement:
A number is called an Armstrong number if the sum of its digits raised to the power of the number of digits is equal to the number itself.
Write a program to check if the given number is Armstrong.
Input Format:
-
A single integer n
Output Format:
-
true if it is Armstrong, otherwise false
Examples:
Input: 153
Output: true
Input: 123
Output: false
✅ Q9. Check for Perfect Number
Problem Statement:
A number is said to be perfect if it is equal to the sum of its proper divisors (excluding itself).
Write a program to check whether a number is perfect.
Input Format:
-
A single integer n
Output Format:
-
true if the number is perfect, otherwise false
Examples:
Input: 28
Output: true
Explanation: 1 + 2 + 4 + 7 + 14 = 28
Input: 15
Output: false
✅ Q10. Check if a Number is Prime
Problem Statement:
Write a program to check whether the given number n is a prime number or not.
Input Format:
-
A single integer n
Output Format:
-
true if the number is prime, otherwise false
Examples:
Input: 7
Output: true
Input: 9
Output: false