What Are the Most Asked DSA Topics in Coding Interviews?

📌 Introduction

If you’re preparing for campus placements or aiming for product-based companies like Amazon, Microsoft, or Google, one thing is certain: you will be tested on DSA (Data Structures and Algorithms).

But here’s the big question students ask:

👉 “Which DSA topics are most commonly asked in coding interviews?”

Let’s break it down by core topics and company-level expectations.

🧩 Core DSA Topics Asked in Almost Every Interview

1. Arrays & Strings

• Most basic but heavily used in interviews.

• Typical problems:

  • Reverse an array

  • Kadane’s Algorithm (maximum subarray sum)

  • Rotate array/string

  • Check palindrome / anagram

2. Linked List

• Common for testing understanding of pointers and dynamic memory.

• Typical problems:

  • Reverse a linked list

  • Detect a cycle (Floyd’s algorithm)

  • Merge two sorted linked lists

3. Stack & Queue

• Popular in both service-based and product-based interviews.

• Typical problems:

  • Balanced parentheses

  • Next greater element

  • Implement queue using stacks

4. Hashing

• Tested for fast lookups and problem-solving ability.

• Typical problems:

  • Two Sum Problem

  • Count frequencies of elements

  • Subarray with given sum

5. Trees

• Binary Trees and Binary Search Trees (BST) are favorites in product-based companies.

• Typical problems:

  • Level order traversal

  • Lowest Common Ancestor (LCA)

  • Height of a tree

6. Graphs

• More common in product-based interviews.

• Typical problems:

  • BFS & DFS traversal

  • Shortest Path (Dijkstra, Bellman-Ford)

  • Detect cycle in a graph

7. Dynamic Programming (DP)

• The toughest yet most rewarding topic.

• Typical problems:

  • Fibonacci sequence (memoization & tabulation)

  • Longest Common Subsequence

  • 0/1 Knapsack problem

  • Coin change problem

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8. Searching & Sorting Algorithms

• Classic questions to test efficiency.

• Typical problems:

  • Binary Search

  • Merge Sort & Quick Sort

  • Search in rotated sorted array

9. Recursion & Backtracking

• Tests problem-solving depth.

• Typical problems:

  • N-Queens problem

  • Rat in a Maze

  • Word search in a grid

10. Heap & Priority Queue

• Used for optimization and greedy problems.

• Typical problems:

  • Kth largest/smallest element

  • Top-K frequent elements

  • Merge K sorted arrays

📊 Company-Wise Focus

Company Type	Topics Mostly Asked	Difficulty
Service-based (TCS, Infosys, Wipro, Cognizant)	Arrays, Strings, Linked List, Stack, Queue	Easy – Medium
Mid-tier (Capgemini, Tech Mahindra, Accenture)	Arrays, Strings, Hashing, Trees	Medium
Product-based (Amazon, Microsoft, Google, Adobe, Flipkart)	Trees, Graphs, DP, Recursion, Heap	Medium – Hard

✅ Summary

The most asked DSA topics in interviews are:

• Arrays & Strings (universally asked)

• Linked List (basic filter)

• Stack, Queue, Hashing (medium-level)

• Trees, Graphs, DP (advanced for product-based companies)

💡 If you’re aiming for placements, focus first on Arrays → Strings → Linked Lists → Stacks/Queues → Trees → DP.

🔎 FAQ

Q1. Which is the single most asked DSA topic?
👉 Arrays & Strings (especially subarray problems).

Q2. Do service-based companies ask DP?
👉 Rarely. Mostly Arrays, Strings, Linked Lists.

Q3. Do I need Graphs for TCS/Infosys?
👉 No. But essential for Amazon/Google.

Q4. How many topics should I cover before placements?
👉 At least 6–7 core topics (Arrays, Strings, Linked List, Stack/Queue, Trees, Hashing, DP basics).