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

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).