HintForge 100
FAANGMaster the 100 most frequently asked problems in top tech companies. Curated list from Amazon, Google, Meta, Apple, Microsoft & more.
100
Total Problems
20
Easy
67
Medium
13
Hard
Showing 100 problems
| # | Problem | Difficulty | Pattern | Companies | Frequency | Action |
|---|---|---|---|---|---|---|
| 1 | Two Sum | EASY | Hash MapArray | GoogleAmazonApple+2 | 🔥 Very High | |
| 2 | Best Time to Buy and Sell Stock | EASY | ArrayGreedy | AmazonMicrosoftBloomberg+1 | 🔥 Very High | |
| 3 | Contains Duplicate | EASY | Hash MapArray | GoogleAppleAdobe | ⚡ High | |
| 4 | Product of Array Except Self | MEDIUM | ArrayPrefix Sum | AmazonMetaApple+1 | 🔥 Very High | |
| 5 | Maximum Subarray | MEDIUM | ArrayDynamic Programming | AmazonMicrosoftLinkedIn+1 | 🔥 Very High | |
| 6 | 3Sum | MEDIUM | Two PointersArray | AmazonMetaGoogle+1 | 🔥 Very High | |
| 7 | Container With Most Water | MEDIUM | Two PointersArray | AmazonGoogleMeta+1 | ⚡ High | |
| 8 | Group Anagrams | MEDIUM | Hash MapString | AmazonGoogleBloomberg | ⚡ High | |
| 9 | Valid Anagram | EASY | Hash MapString | AmazonMetaMicrosoft | ⚡ High | |
| 10 | Longest Consecutive Sequence | MEDIUM | Hash MapArray | GoogleAmazonMeta | ⚡ High | |
| 11 | Subarray Sum Equals K | MEDIUM | Hash MapPrefix Sum | MetaGoogleAmazon | 🔥 Very High | |
| 12 | Top K Frequent Elements | MEDIUM | Hash MapHeap | AmazonMetaGoogle | ⚡ High | |
| 13 | Longest Substring Without Repeating Characters | MEDIUM | Hash MapSliding Window | AmazonGoogleMeta+1 | 🔥 Very High | |
| 14 | Merge Intervals | MEDIUM | ArraySorting | MetaGoogleAmazon+1 | 🔥 Very High | |
| 15 | Insert Interval | MEDIUM | ArraySorting | GoogleAmazonMeta | ⚡ High | |
| 16 | Valid Palindrome | EASY | Two PointersString | MetaAmazonApple | ⚡ High | |
| 17 | Two Sum II - Input Array Is Sorted | MEDIUM | Two PointersArray | AmazonGoogle | ⚡ High | |
| 18 | 3Sum Closest | MEDIUM | Two PointersArray | AmazonGoogle | 📊 Medium | |
| 19 | Remove Nth Node From End of List | MEDIUM | Two PointersLinked List | AmazonMetaGoogle | ⚡ High | |
| 20 | Trapping Rain Water | HARD | Two PointersArray | GoogleAmazonMeta+1 | 🔥 Very High | |
| 21 | Move Zeroes | EASY | Two PointersArray | MetaGoogleApple | ⚡ High | |
| 22 | Sort Colors | MEDIUM | Two PointersArray | MetaMicrosoftAmazon | 📊 Medium | |
| 23 | Squares of a Sorted Array | EASY | Two PointersArray | MetaGoogle | 📊 Medium | |
| 24 | Reverse Linked List | EASY | Linked List | AmazonMetaGoogle+2 | 🔥 Very High | |
| 25 | Merge Two Sorted Lists | EASY | Linked ListRecursion | AmazonMetaApple+1 | 🔥 Very High | |
| 26 | Linked List Cycle | EASY | Linked ListTwo Pointers | AmazonMetaGoogle | 🔥 Very High | |
| 27 | Reorder List | MEDIUM | Linked ListTwo Pointers | MetaAmazonGoogle | ⚡ High | |
| 28 | Add Two Numbers | MEDIUM | Linked ListMath | AmazonMetaGoogle+1 | 🔥 Very High | |
| 29 | Copy List with Random Pointer | MEDIUM | Linked ListHash Map | AmazonMetaGoogle | ⚡ High | |
| 30 | Merge K Sorted Lists | HARD | Linked ListHeap | AmazonMetaGoogle+1 | 🔥 Very High | |
| 31 | Binary Search | EASY | Binary Search | AmazonGoogleMeta | 🔥 Very High | |
| 32 | Search in Rotated Sorted Array | MEDIUM | Binary SearchArray | MetaAmazonGoogle+1 | 🔥 Very High | |
| 33 | Find Minimum in Rotated Sorted Array | MEDIUM | Binary SearchArray | AmazonMetaGoogle | ⚡ High | |
| 34 | Koko Eating Bananas | MEDIUM | Binary Search | MetaGoogle | 📊 Medium | |
| 35 | Search a 2D Matrix | MEDIUM | Binary SearchMatrix | AmazonGoogleMeta | ⚡ High | |
| 36 | Time Based Key-Value Store | MEDIUM | Binary SearchHash Map | GoogleAmazon | 📊 Medium | |
| 37 | Median of Two Sorted Arrays | HARD | Binary SearchArray | GoogleMetaAmazon+1 | 🔥 Very High | |
| 38 | Valid Parentheses | EASY | StackString | AmazonMetaGoogle+2 | 🔥 Very High | |
| 39 | Min Stack | MEDIUM | StackDesign | AmazonGoogleMeta | ⚡ High | |
| 40 | Daily Temperatures | MEDIUM | StackMonotonic Stack | AmazonMetaGoogle | ⚡ High | |
| 41 | Evaluate Reverse Polish Notation | MEDIUM | StackArray | AmazonMeta | 📊 Medium | |
| 42 | Largest Rectangle in Histogram | HARD | StackMonotonic Stack | GoogleAmazonMeta | ⚡ High | |
| 43 | Generate Parentheses | MEDIUM | StackBacktracking | MetaGoogleAmazon | 🔥 Very High | |
| 44 | Maximum Depth of Binary Tree | EASY | TreeDFS | AmazonMetaGoogle | 🔥 Very High | |
| 45 | Same Tree | EASY | TreeDFS | MetaAmazon | ⚡ High | |
| 46 | Invert Binary Tree | EASY | TreeDFS | GoogleMetaAmazon | 🔥 Very High | |
| 47 | Symmetric Tree | EASY | TreeDFS | MetaAmazonMicrosoft | ⚡ High | |
| 48 | Binary Tree Level Order Traversal | MEDIUM | TreeBFS | AmazonMetaGoogle+1 | 🔥 Very High | |
| 49 | Validate Binary Search Tree | MEDIUM | TreeDFS | AmazonMetaGoogle+1 | 🔥 Very High | |
| 50 | Lowest Common Ancestor of BST | MEDIUM | TreeBST | AmazonMetaGoogle | ⚡ High | |
| 51 | Kth Smallest Element in a BST | MEDIUM | TreeBST | AmazonGoogleMeta | ⚡ High | |
| 52 | Binary Tree Right Side View | MEDIUM | TreeBFS | MetaAmazonGoogle | ⚡ High | |
| 53 | Construct Binary Tree from Preorder and Inorder | MEDIUM | TreeDFS | MetaAmazonGoogle | ⚡ High | |
| 54 | Serialize and Deserialize Binary Tree | HARD | TreeDesign | AmazonMetaGoogle | 🔥 Very High | |
| 55 | Diameter of Binary Tree | EASY | TreeDFS | MetaGoogleAmazon | ⚡ High | |
| 56 | Subtree of Another Tree | EASY | TreeDFS | MetaAmazon | 📊 Medium | |
| 57 | Binary Tree Maximum Path Sum | HARD | TreeDFS | MetaAmazonGoogle | 🔥 Very High | |
| 58 | Count Good Nodes in Binary Tree | MEDIUM | TreeDFS | AmazonGoogle | 📊 Medium | |
| 59 | Kth Largest Element in an Array | MEDIUM | HeapArray | AmazonMetaGoogle | 🔥 Very High | |
| 60 | Find Median from Data Stream | HARD | HeapDesign | GoogleAmazonMeta | 🔥 Very High | |
| 61 | Task Scheduler | MEDIUM | HeapGreedy | MetaGoogleAmazon | ⚡ High | |
| 62 | K Closest Points to Origin | MEDIUM | HeapArray | AmazonMetaGoogle | ⚡ High | |
| 63 | Last Stone Weight | EASY | Heap | Amazon | 📊 Medium | |
| 64 | Subsets | MEDIUM | BacktrackingArray | MetaAmazonGoogle | 🔥 Very High | |
| 65 | Combination Sum | MEDIUM | BacktrackingArray | AmazonMetaGoogle | 🔥 Very High | |
| 66 | Permutations | MEDIUM | BacktrackingArray | MetaAmazonGoogle | 🔥 Very High | |
| 67 | Word Search | MEDIUM | BacktrackingMatrix | AmazonMetaGoogle+1 | 🔥 Very High | |
| 68 | Palindrome Partitioning | MEDIUM | BacktrackingString | AmazonGoogle | 📊 Medium | |
| 69 | Letter Combinations of a Phone Number | MEDIUM | BacktrackingString | AmazonMetaGoogle | ⚡ High | |
| 70 | N-Queens | HARD | Backtracking | GoogleAmazon | 📊 Medium | |
| 71 | Climbing Stairs | EASY | Dynamic Programming | AmazonGoogleAdobe | 🔥 Very High | |
| 72 | House Robber | MEDIUM | Dynamic Programming | AmazonGoogleApple | ⚡ High | |
| 73 | House Robber II | MEDIUM | Dynamic Programming | AmazonGoogle | 📊 Medium | |
| 74 | Longest Palindromic Substring | MEDIUM | Dynamic ProgrammingString | AmazonMetaGoogle+1 | 🔥 Very High | |
| 75 | Palindromic Substrings | MEDIUM | Dynamic ProgrammingString | MetaAmazon | 📊 Medium | |
| 76 | Decode Ways | MEDIUM | Dynamic ProgrammingString | MetaGoogleAmazon | ⚡ High | |
| 77 | Coin Change | MEDIUM | Dynamic Programming | AmazonGoogleMeta | 🔥 Very High | |
| 78 | Maximum Product Subarray | MEDIUM | Dynamic ProgrammingArray | AmazonLinkedIn | ⚡ High | |
| 79 | Word Break | MEDIUM | Dynamic ProgrammingString | AmazonMetaGoogle | 🔥 Very High | |
| 80 | Longest Increasing Subsequence | MEDIUM | Dynamic ProgrammingArray | AmazonMicrosoftGoogle | 🔥 Very High | |
| 81 | Unique Paths | MEDIUM | Dynamic ProgrammingMath | AmazonGoogleMeta | ⚡ High | |
| 82 | Jump Game | MEDIUM | Dynamic ProgrammingGreedy | AmazonMetaGoogle | ⚡ High | |
| 83 | Edit Distance | MEDIUM | Dynamic ProgrammingString | GoogleAmazonMeta | ⚡ High | |
| 84 | Regular Expression Matching | HARD | Dynamic ProgrammingString | GoogleMetaAmazon | ⚡ High | |
| 85 | Longest Common Subsequence | MEDIUM | Dynamic ProgrammingString | AmazonGoogle | ⚡ High | |
| 86 | Number of Islands | MEDIUM | GraphDFS | AmazonMetaGoogle+1 | 🔥 Very High | |
| 87 | Clone Graph | MEDIUM | GraphDFS | MetaAmazonGoogle | 🔥 Very High | |
| 88 | Pacific Atlantic Water Flow | MEDIUM | GraphDFS | GoogleAmazon | 📊 Medium | |
| 89 | Course Schedule | MEDIUM | GraphTopological Sort | AmazonMetaGoogle | 🔥 Very High | |
| 90 | Course Schedule II | MEDIUM | GraphTopological Sort | AmazonMetaGoogle | ⚡ High | |
| 91 | Rotting Oranges | MEDIUM | GraphBFS | AmazonBloomberg | ⚡ High | |
| 92 | Word Ladder | HARD | GraphBFS | AmazonMetaGoogle | ⚡ High | |
| 93 | Alien Dictionary | HARD | GraphTopological Sort | GoogleMetaAmazon | ⚡ High | |
| 94 | Graph Valid Tree | MEDIUM | GraphUnion Find | MetaGoogle | 📊 Medium | |
| 95 | Network Delay Time | MEDIUM | GraphDijkstra | AmazonGoogle | 📊 Medium | |
| 96 | LRU Cache | MEDIUM | DesignHash Map+1 | AmazonMetaGoogle+2 | 🔥 Very High | |
| 97 | Implement Trie | MEDIUM | TrieDesign | AmazonMetaGoogle | 🔥 Very High | |
| 98 | Design Add and Search Words Data Structure | MEDIUM | TrieDesign | MetaAmazon | 📊 Medium | |
| 99 | Word Search II | HARD | TrieBacktracking | AmazonMetaGoogle | ⚡ High | |
| 100 | Sliding Window Maximum | HARD | Sliding WindowMonotonic Stack | AmazonGoogleMeta | 🔥 Very High |
💡 Pro Tip: Start with Easy problems, then progress to Medium and Hard.
Problems are ordered by pattern to help you master one concept at a time.