Coding interview prep
Interview Problems
Classic problems asked by big tech companies, each solved the easy way: understand the problem, try brute force, spot the pattern, then write the clean solution in Python.
51 problems
20 patterns
New to DSA? Learn the patterns first ❯
| Solved | # | Problem | Pattern | Difficulty | Often asked at |
|---|---|---|---|---|---|
| 1 | Two Sum | Hashing | Easy | Amazon, Google, Meta, Microsoft, Apple, Adobe | |
| 2 | Contains Duplicate | Hashing | Easy | Amazon, Apple, Microsoft, Adobe, Yahoo | |
| 3 | Valid Anagram | Hashing | Easy | Amazon, Google, Microsoft, Bloomberg, Uber | |
| 4 | Group Anagrams | Hashing | Medium | Amazon, Meta, Google, Microsoft, Uber, Goldman Sachs | |
| 5 | Top K Frequent Elements | Heap | Medium | Amazon, Meta, Google, Microsoft, Yelp, Oracle | |
| 6 | Product of Array Except Self | Prefix Sum | Medium | Amazon, Meta, Microsoft, Apple, Asana, Lyft | |
| 7 | Longest Consecutive Sequence | Hashing | Medium | Google, Amazon, Meta, Microsoft, Spotify | |
| 8 | Valid Palindrome | Two Pointers | Easy | Meta, Amazon, Microsoft, Apple, Spotify | |
| 9 | Container With Most Water | Two Pointers | Medium | Amazon, Google, Meta, Microsoft, Goldman Sachs, Adobe | |
| 10 | 3Sum | Two Pointers | Medium | Meta, Amazon, Google, Microsoft, Apple, Adobe, Bloomberg | |
| 11 | Trapping Rain Water | Two Pointers | Hard | Amazon, Google, Goldman Sachs, Meta, Microsoft, Apple, Bloomberg | |
| 12 | Best Time to Buy and Sell Stock | Greedy | Easy | Amazon, Meta, Microsoft, Google, Goldman Sachs, Bloomberg, Uber | |
| 13 | Longest Substring Without Repeating Characters | Sliding Window | Medium | Amazon, Google, Meta, Microsoft, Bloomberg, Adobe, Apple | |
| 14 | Minimum Window Substring | Sliding Window | Hard | Meta, Google, Amazon, LinkedIn, Uber, Airbnb, Microsoft | |
| 15 | Subarray Sum Equals K | Prefix Sum | Medium | Meta, Google, Amazon, Microsoft, Goldman Sachs, Twitter | |
| 16 | Maximum Subarray | Kadane | Medium | Amazon, Microsoft, Apple, LinkedIn, Google, Bloomberg, Cisco | |
| 17 | Binary Search | Binary Search | Easy | Google, Amazon, Microsoft, Apple, Meta, Adobe | |
| 18 | Search in Rotated Sorted Array | Binary Search | Medium | Meta, Amazon, Microsoft, Google, LinkedIn, Bloomberg, Uber | |
| 19 | Koko Eating Bananas | Binary Search | Medium | Google, Amazon, Meta, Airbnb, DoorDash | |
| 20 | Valid Parentheses | Stack | Easy | Amazon, Google, Meta, Microsoft, Bloomberg, LinkedIn, Spotify | |
| 21 | Min Stack | Stack | Medium | Amazon, Bloomberg, Microsoft, Google, Oracle | |
| 22 | Daily Temperatures | Monotonic Stack | Medium | Amazon, Google, Meta, Microsoft, Uber, Bloomberg | |
| 23 | Largest Rectangle in Histogram | Monotonic Stack | Hard | Google, Amazon, Microsoft, Meta, Uber, Goldman Sachs | |
| 24 | Reverse Linked List | Linked List | Easy | Amazon, Microsoft, Apple, Google, Meta, Adobe, Yahoo | |
| 25 | Merge Two Sorted Lists | Linked List | Easy | Amazon, Microsoft, Apple, Google, Meta, Adobe, Bloomberg | |
| 26 | Linked List Cycle | Fast & Slow Pointers | Easy | Amazon, Microsoft, Bloomberg, Goldman Sachs, Oracle, Yahoo | |
| 27 | LRU Cache | Hashing | Medium | Amazon, Microsoft, Meta, Google, Apple, Oracle, Uber, Salesforce | |
| 28 | Maximum Depth of Binary Tree | Trees | Easy | Amazon, LinkedIn, Microsoft, Google, Apple, Adobe | |
| 29 | Invert Binary Tree | Trees | Easy | Google, Amazon, Meta, Microsoft, Apple | |
| 30 | Binary Tree Level Order Traversal | Trees | Medium | Amazon, Meta, Microsoft, LinkedIn, Bloomberg, Apple | |
| 31 | Validate Binary Search Tree | BST | Medium | Amazon, Meta, Microsoft, Bloomberg, Google, Apple | |
| 32 | Lowest Common Ancestor of a Binary Tree | Trees | Medium | Meta, Amazon, Microsoft, LinkedIn, Google, Apple | |
| 33 | Kth Largest Element in an Array | Heap | Medium | Meta, Amazon, Microsoft, Google, LinkedIn, Spotify | |
| 34 | Merge k Sorted Lists | Heap | Hard | Amazon, Meta, Google, Microsoft, Uber, LinkedIn, Airbnb | |
| 35 | Number of Islands | Grids | Medium | Amazon, Google, Microsoft, Meta, Uber, Bloomberg, Apple, Oracle | |
| 36 | Rotting Oranges | Grids | Medium | Amazon, Microsoft, Google, Meta, Bloomberg | |
| 37 | Course Schedule | Topological Sort | Medium | Amazon, Google, Meta, Microsoft, Uber, Apple, Airbnb | |
| 38 | Network Delay Time | Graphs | Medium | Google, Amazon, Microsoft, Uber, Akamai | |
| 39 | Word Ladder | Graphs | Hard | Amazon, Meta, Google, LinkedIn, Microsoft, Snapchat | |
| 40 | Subsets | Backtracking | Medium | Meta, Amazon, Google, Microsoft, Bloomberg, Uber | |
| 41 | Permutations | Backtracking | Medium | Microsoft, Amazon, Meta, Google, LinkedIn, Bloomberg | |
| 42 | Combination Sum | Backtracking | Medium | Amazon, Airbnb, Meta, Microsoft, Uber, Snapchat | |
| 43 | Climbing Stairs | Dynamic Programming | Easy | Amazon, Google, Adobe, Apple, Microsoft, Uber | |
| 44 | House Robber | Dynamic Programming | Medium | Amazon, Google, Microsoft, Cisco, Airbnb, Apple | |
| 45 | Coin Change | Dynamic Programming | Medium | Amazon, Google, Microsoft, Goldman Sachs, Apple, Bloomberg, Paytm | |
| 46 | Longest Increasing Subsequence | Dynamic Programming | Medium | Microsoft, Amazon, Google, Meta, Apple, Samsung | |
| 47 | Longest Common Subsequence | Dynamic Programming | Medium | Amazon, Google, Microsoft, Meta, Bloomberg, Adobe | |
| 48 | Edit Distance | Dynamic Programming | Hard | Google, Amazon, Microsoft, Meta, Bloomberg, Grammarly | |
| 49 | Merge Intervals | Intervals | Medium | Google, Meta, Amazon, Microsoft, Bloomberg, LinkedIn, Salesforce | |
| 50 | Meeting Rooms II | Intervals | Medium | Google, Amazon, Meta, Microsoft, Uber, Bloomberg, Oracle | |
| 51 | Jump Game | Greedy | Medium | Amazon, Microsoft, Google, Meta, Apple, Adobe |
No problems match these filters.
Company names show where a problem is commonly reported in interviews. Questions vary by team and year, so learn the pattern rather than memorising answers.