DSA Roadmap for Service-Based Companies – Focused for 5–10 LPA Roles

 

🔹 Step 1: Understand the Pattern (Day 1)

Before you jump into DSA, know what’s actually asked.

Common Topics in Tests/Interviews:

• Arrays

• Strings

• Sorting & Searching

• Recursion

• HashMap

• Stack & Queue (Basics)

• Time & Space Complexity

Start slow. Don’t rush.

🔹 Step 2: Arrays & Strings (Days 2–7)

These two topics alone cover 40–50% of questions asked in TCS, Wipro, and Infosys.

What to do:

• Learn basics: syntax, loops, array operations

• Practice 10 easy problems first

• Focus on patterns: two-pointer, sliding window, frequency count

Popular Questions:

• Reverse an array

• Move all zeros to end

• Check if string is palindrome

• Find duplicates in array

Use platforms like LeetCode (Easy filter), HackerRank, or our Campusmonk Sheets.

🔹 Step 3: Recursion + Basic Patterns (Days 8–12)

You don’t need to master deep recursion, just the basics.

What to cover:

• Factorial

• Fibonacci

• Print subsets of string

• Power of a number

Why this matters: Many pattern-based questions (like backtracking) start with recursion logic.

🔹 Step 4: Sorting, Searching & HashMaps (Days 13–17)

Understand sorting logic, not just how to write it.

Topics to learn:

• Bubble, Selection, Insertion Sort

• Binary Search (on array)

• HashMap basics (count frequency, find pairs)

Most Asked Problems:

• Two Sum (using HashMap)

• Sort array of 0s, 1s, 2s

• Frequency of each element

• Find missing number in array

🔹 Step 5: Practice Problem Solving (Days 18–25)

Now that you know concepts, let’s apply.

Create a habit:

• 2 Easy + 1 Medium question daily

• Time yourself

• Use Campusmonk tracker or LeetCode explore

Topics to revise:

• Arrays & Strings

• Sorting

• Hashing

• Recursion basics

🔹 Step 6: Learn Stack & Queue Basics (Days 26–28)

No need to go deep. Just the fundamentals are enough.

Learn:

• Stack operations (push, pop)

• Queue operations (enqueue, dequeue)

• Balanced parentheses

• Prefix/Postfix expression (just intro level)

These come in aptitude + technical rounds sometimes.

🔹 Step 7: Final Revision + Mock Tests (Days 29–30)

Plan:

• Revise all solved problems

• Attempt 2 mock tests (Campusmonk, PrepInsta, HackerRank)

• Solve 1 HR + 1 Aptitude + 1 Coding mock paper

Tips:

• Focus on speed + accuracy

• Note down mistakes in a separate notebook

• Don’t study new topics on last 2 days

✅ What You Can Skip (for Now)

• Trees, Graphs, and DP (for service-based roles)

• Deep OOPs concepts

• System design, advanced SQL