✨ Introduction
Cracking interviews at top product-based companies like Google, Amazon, Microsoft, Flipkart, Adobe, Swiggy, and others requires more than just basic coding knowledge. These companies evaluate a candidate’s problem-solving ability, data structures understanding, and real-world application of algorithms.
To help you streamline your preparation, I’ve compiled a list of the top 50 most asked DSA questions, based on recurring patterns from actual interviews and online coding platforms like LeetCode, GeeksforGeeks, and InterviewBit.
Whether you are a fresher or a working professional planning a switch, this list will help you focus on what matters most.
📚 Why These Questions?
These problems are selected based on:
- High frequency in interviews across top tech companies
- Coverage of all important DSA topics (Arrays, Strings, Linked List, Trees, Graphs, Dynamic Programming, etc.)
- Skill depth — from beginner to advanced problems
- Company tags — Amazon, Google, Microsoft, Adobe, etc.
✅ How to Use This List
- Bookmark this page for quick access.
- Practice one question per topic daily.
- Focus on understanding the approach, not just getting the right output.
- Use the attached platform links to solve and submit.
- Track your progress in a Notion or Google Sheet.
🧩 50 Most Asked DSA Problems
| # | Problem Title | Topic(s) | Companies | Practice Link |
|---|---|---|---|---|
| 1 | Two Sum | Arrays, Hashing | Amazon, Microsoft, Adobe | LeetCode |
| 2 | Longest Substring Without Repeating Characters | Sliding Window, Hashing | Google, Atlassian | LeetCode |
| 3 | Merge Intervals | Sorting, Intervals | Amazon, Facebook, Uber | LeetCode |
| 4 | Detect Cycle in a Linked List | Linked List, Two Pointers | Microsoft, Paytm | LeetCode |
| 5 | LRU Cache | Design, Hashing, Linked List | Amazon, Adobe, Flipkart | LeetCode |
| 6 | Kth Largest Element in an Array | Heap, QuickSelect | Amazon, Microsoft | LeetCode |
| 7 | Clone Graph | Graph, DFS, BFS | Google, Meta | LeetCode |
| 8 | Word Ladder | BFS, Graph | Google, Amazon | LeetCode |
| 9 | Top K Frequent Elements | Heap, HashMap | Amazon, Adobe, Paytm | LeetCode |
| 10 | Search in Rotated Sorted Array | Binary Search | Google, Microsoft | LeetCode |
| 11 | Longest Palindromic Substring | Dynamic Programming | Adobe, Microsoft | LeetCode |
| 12 | Find Median from Data Stream | Heap, Design | Google, Amazon | LeetCode |
| 13 | Trapping Rain Water | Two Pointers, Stack | Amazon, Adobe | LeetCode |
| 14 | Minimum Window Substring | Sliding Window | Google, Microsoft | LeetCode |
| 15 | Course Schedule | Graph, Topological Sort | Google, Uber | LeetCode |
| 16 | Implement Trie (Prefix Tree) | Trie, Design | Microsoft, Google | LeetCode |
| 17 | Valid Parentheses | Stack | Adobe, Flipkart | LeetCode |
| 18 | Binary Tree Level Order Traversal | Tree, BFS | Amazon, Microsoft | LeetCode |
| 19 | Lowest Common Ancestor of a Binary Tree | Tree, DFS | Google, Microsoft | LeetCode |
| 20 | Number of Islands | DFS, BFS | Amazon, Google, Flipkart | LeetCode |
| 21 | Find All Anagrams in a String | Sliding Window, Hashing | Atlassian, Amazon | LeetCode |
| 22 | Reverse Nodes in k-Group | Linked List, Recursion | Google, Amazon | LeetCode |
| 23 | Maximum Subarray | Dynamic Programming | Paytm, Amazon | LeetCode |
| 24 | Merge k Sorted Lists | Heap, Linked List | Amazon, Google | LeetCode |
| 25 | Rotting Oranges | BFS, Matrix | Amazon, Microsoft | LeetCode |
| 26 | Coin Change | Dynamic Programming | Google, Amazon | LeetCode |
| 27 | Subsets | Backtracking | Facebook, Google | LeetCode |
| 28 | Combination Sum | Backtracking | Amazon, Microsoft | LeetCode |
| 29 | Word Break | Dynamic Programming | Google, Microsoft | LeetCode |
| 30 | Longest Increasing Subsequence | Dynamic Programming | Amazon, Adobe | LeetCode |
| 31 | Next Permutation | Array, Backtracking | Amazon, Facebook | LeetCode |
| 32 | Longest Substring Without Repeating Characters | String, Sliding Window | Amazon, Facebook | LeetCode |
| 33 | Merge Intervals | Array, Sorting | Google, Facebook | LeetCode |
| 34 | Subsets | Backtracking | Microsoft, Amazon | LeetCode |
| 35 | Rotate Image | Matrix, Array | Google, Amazon | LeetCode |
| 36 | Valid Sudoku | Matrix, HashMap | Amazon, Facebook | LeetCode |
| 37 | Set Matrix Zeroes | Matrix, Array | Google, Microsoft | LeetCode |
| 38 | Combinations | Backtracking | Amazon, Microsoft | LeetCode |
| 39 | Combination Sum | Backtracking, Recursion | Google, Microsoft | LeetCode |
| 40 | Word Search | Backtracking, DFS | Amazon, Microsoft | LeetCode |
| 41 | Maximum Product Subarray | Dynamic Programming | Amazon, Facebook | LeetCode |
| 42 | Palindromic Substrings | Dynamic Programming | Adobe, Amazon | LeetCode |
| 43 | Find Peak Element | Binary Search | Amazon, Google | LeetCode |
| 44 | Sliding Window Maximum | Heap, Deque | Amazon, Microsoft | LeetCode |
| 45 | Maximum Depth of Binary Tree | Tree, DFS | Microsoft, Amazon | LeetCode |
| 46 | Construct Binary Tree from Preorder and Inorder Traversal | Tree, Recursion | Amazon, Google | LeetCode |
| 47 | Diameter of Binary Tree | Tree, DFS | Amazon, Microsoft | LeetCode |
| 48 | Minimum Path Sum | Dynamic Programming | Amazon, Google | LeetCode |
| 49 | Unique Paths | Dynamic Programming | Google, Amazon | LeetCode |
| 50 | Edit Distance | Dynamic Programming | Google, Facebook | LeetCode |
📈 Topics Covered
This list includes hand-picked problems from the most important DSA topics:
- Arrays & Hashing
- Strings
- Sliding Window
- Two Pointers
- Linked List
- Stack & Queue
- Trees & Binary Search Trees
- Graphs & BFS/DFS
- Backtracking
- Dynamic Programming
- Greedy
- Heap/Priority Queue
- Binary Search
- Trie
- Recursion & Divide and Conquer
📢 Final Words
Solving these questions will not only boost your confidence but also make you interview-ready for top tech companies. Be consistent, understand the patterns, and practice smart.
If you found this helpful, do share it with your friends and colleagues who are also preparing for tech interviews.
