DSA Interview Questions & Answers (Top 50 Problems)
The most common DSA interview questions and answers asked at Google, Amazon, Meta, and Microsoft — organized by topic with key problems, patterns, and preparation tips.
DSA Topics — What You Need to Know
Each topic links to its pattern page with templates, tips, and curated problems.
Arrays & Strings
Difficulty: Easy → Medium
Key problems: Two Sum, Maximum Subarray, Product of Array Except Self, Longest Substring Without Repeating Characters
Linked Lists
Difficulty: Easy → Medium
Key problems: Reverse Linked List, Linked List Cycle, Merge Two Sorted Lists, Remove Nth Node
Trees & BST
Difficulty: Easy → Hard
Key problems: Maximum Depth, Validate BST, Lowest Common Ancestor, Binary Tree Maximum Path Sum
Graphs
Difficulty: Medium → Hard
Key problems: Number of Islands, Course Schedule, Clone Graph, Word Ladder
Dynamic Programming
Difficulty: Easy → Hard
Key problems: Climbing Stairs, Coin Change, Longest Common Subsequence, Edit Distance
Binary Search
Difficulty: Easy → Medium
Key problems: Binary Search, Search in Rotated Sorted Array, Koko Eating Bananas, Find Peak Element
Stacks & Queues
Difficulty: Easy → Hard
Key problems: Valid Parentheses, Min Stack, Daily Temperatures, Largest Rectangle in Histogram
Hash Maps & Sets
Difficulty: Easy → Medium
Key problems: Two Sum, Group Anagrams, Top K Frequent, Longest Consecutive Sequence
Heaps & Priority Queues
Difficulty: Medium → Hard
Key problems: Kth Largest Element, Find Median from Data Stream, Merge K Sorted Lists, Task Scheduler
Backtracking
Difficulty: Medium → Hard
Key problems: Subsets, Permutations, Combination Sum, Word Search
Curated Problem Lists
Frequently Asked Questions
What are DSA interview questions?
DSA interview questions test your knowledge of Data Structures and Algorithms. They typically ask you to solve coding problems using arrays, linked lists, trees, graphs, hash maps, stacks, queues, heaps, and dynamic programming. Questions range from easy (Two Sum) to hard (Edit Distance) and are asked at FAANG and top tech companies.
Is DSA still relevant in 2026 for interviews?
Yes — DSA remains the foundation of technical interviews at Google, Amazon, Meta, Microsoft, and most tech companies. While AI tools have changed how engineers work, companies still test problem-solving ability through DSA questions. The format may evolve (more system design for seniors), but DSA is still required for most software engineering roles.
What are the most common DSA interview topics?
The most frequently tested DSA topics: Arrays & Strings (Two Pointers, Sliding Window), Hash Maps (frequency counting, two-sum variants), Trees (DFS, BFS, BST validation), Graphs (BFS, DFS, cycle detection, topological sort), Dynamic Programming (1D and 2D), Binary Search, Linked Lists (cycle detection, reversal), and Stacks (monotonic stack, valid parentheses).
How many DSA problems should I solve for interviews?
Quality over quantity: 75-150 well-chosen problems across all core patterns is more effective than grinding 500+ random ones. Focus on mastering each pattern with 3-5 representative problems. The Blind 75 and NeetCode 150 lists are the most efficient starting points.
How do I prepare for DSA interviews from scratch?
Start with basic data structures (arrays, linked lists, stacks, queues, hash maps). Then learn algorithms (sorting, searching, BFS, DFS). Then practice pattern-based problems. Use a structured roadmap: Week 1-2: Arrays, Strings, Hash Maps. Week 3-4: Linked Lists, Stacks, Binary Search. Week 5-6: Trees, Graphs. Week 7-8: Dynamic Programming. Follow the DSA Roadmap on Coding Prep Guide.