NeetCode 150 is a curated list of 150 essential LeetCode problems compiled by a Google engineer. This collection represents the most important algorithmic patterns and concepts frequently tested in FAANG and top tech company interviews. Each problem has been selected to maximize your interview preparation efficiency.
🎯 Perfect for FAANG Interview Preparation | 🔥 150 Handpicked Problems | ✅ Pattern-Based Learning
- ✨ Curated by Industry Expert: Selected by a Google engineer based on real interview experience
- 🎯 Maximum Coverage: Covers all major algorithmic patterns and data structures
- ⚡ Efficient Preparation: Focus on quality over quantity - 150 problems vs. 2000+ on LeetCode
- 📈 Proven Success: Used by thousands to land offers at top tech companies
- 🎥 Video Solutions: Comprehensive video explanations available for every problem
| Category | Problems | Difficulty Distribution | Key Patterns |
|---|---|---|---|
| Arrays & Hashing | 9 | 2 Easy, 6 Medium, 1 Hard | Two Pointers, Hash Maps, Prefix Sums |
| Two Pointers | 5 | 1 Easy, 4 Medium | Left-Right Pointers, Fast-Slow Pointers |
| Sliding Window | 6 | 2 Easy, 3 Medium, 1 Hard | Fixed/Variable Window, String Problems |
| Stack | 7 | 2 Easy, 4 Medium, 1 Hard | Monotonic Stack, Expression Parsing |
| Binary Search | 7 | 2 Easy, 5 Medium | Search Space Reduction, Peak Finding |
| Linked List | 11 | 2 Easy, 8 Medium, 1 Hard | Two Pointers, Reversal, Cycle Detection |
| Trees | 15 | 3 Easy, 10 Medium, 2 Hard | DFS, BFS, Tree Construction |
| Tries | 3 | 2 Medium, 1 Hard | Prefix Trees, Word Search |
| Heap/Priority Queue | 7 | 1 Easy, 5 Medium, 1 Hard | K-Elements, Merge Operations |
| Backtracking | 9 | 6 Medium, 3 Hard | Permutations, Combinations, Subsets |
| Graphs | 13 | 3 Medium, 10 Hard | DFS, BFS, Union Find, Topological Sort |
| Advanced Graphs | 6 | 6 Hard | Shortest Path, MST, Advanced Algorithms |
| 1-D Dynamic Programming | 12 | 1 Easy, 8 Medium, 3 Hard | State Transitions, Optimization |
| 2-D Dynamic Programming | 11 | 8 Medium, 3 Hard | Grid DP, String DP |
| Greedy | 8 | 2 Easy, 4 Medium, 2 Hard | Local Optimal Choices |
| Intervals | 5 | 1 Easy, 3 Medium, 1 Hard | Merging, Scheduling |
| Math & Geometry | 8 | 3 Easy, 4 Medium, 1 Hard | Number Theory, Computational Geometry |
| Bit Manipulation | 7 | 3 Easy, 4 Medium | Bitwise Operations, XOR Tricks |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 1 | Contains Duplicate | Easy | Hash Set | All FAANG |
| 2 | Valid Anagram | Easy | Character Count | All FAANG |
| 3 | Two Sum | Easy | Hash Map | All FAANG |
| 4 | Group Anagrams | Medium | Hash Map, Sorting | Google, Amazon |
| 5 | Top K Frequent Elements | Medium | Heap, Hash Map | All FAANG |
| 6 | Product of Array Except Self | Medium | Prefix/Suffix Product | Meta, Apple |
| 7 | Valid Sudoku | Medium | Hash Set, Matrix | Apple, Amazon |
| 8 | Encode and Decode Strings | Medium | String Manipulation | Google, Meta |
| 9 | Longest Consecutive Sequence | Hard | Union Find, Hash Set | Google, Meta |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 10 | Valid Palindrome | Easy | Two Pointers | Meta, Apple |
| 11 | Two Sum II - Input Array Is Sorted | Medium | Two Pointers | Amazon, Google |
| 12 | 3Sum | Medium | Two Pointers, Sort | All FAANG |
| 13 | Container With Most Water | Medium | Two Pointers | All FAANG |
| 14 | Trapping Rain Water | Hard | Two Pointers | Amazon, Google |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 15 | Best Time to Buy and Sell Stock | Easy | Single Pass | All FAANG |
| 16 | Longest Substring Without Repeating Characters | Medium | Variable Window | All FAANG |
| 17 | Longest Repeating Character Replacement | Medium | Variable Window | Google, Meta |
| 18 | Permutation in String | Medium | Fixed Window | Meta, Amazon |
| 19 | Minimum Window Substring | Hard | Variable Window | Meta, Amazon |
| 20 | Sliding Window Maximum | Hard | Deque, Fixed Window | Amazon, Google |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 21 | Valid Parentheses | Easy | Stack Matching | All FAANG |
| 22 | Min Stack | Medium | Stack Design | Amazon, Apple |
| 23 | Evaluate Reverse Polish Notation | Medium | Stack Evaluation | Amazon, Meta |
| 24 | Generate Parentheses | Medium | Backtracking, Stack | Google, Meta |
| 25 | Daily Temperatures | Medium | Monotonic Stack | Amazon, Google |
| 26 | Car Fleet | Medium | Stack, Sorting | Tesla, Amazon |
| 27 | Largest Rectangle in Histogram | Hard | Monotonic Stack | Google, Amazon |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 28 | Binary Search | Easy | Basic Binary Search | All FAANG |
| 29 | Search a 2D Matrix | Medium | Matrix Binary Search | Amazon, Apple |
| 30 | Koko Eating Bananas | Medium | Binary Search on Answer | Google, Meta |
| 31 | Find Minimum in Rotated Sorted Array | Medium | Rotated Array | All FAANG |
| 32 | Search in Rotated Sorted Array | Medium | Rotated Array | All FAANG |
| 33 | Time Based Key-Value Store | Medium | Binary Search, Design | Google, Amazon |
| 34 | Median of Two Sorted Arrays | Hard | Binary Search, Arrays | Google, Amazon |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 35 | Reverse Linked List | Easy | Iterative/Recursive | All FAANG |
| 36 | Merge Two Sorted Lists | Easy | Two Pointers | All FAANG |
| 37 | Reorder List | Medium | Multiple Pointers | Meta, Amazon |
| 38 | Remove Nth Node From End of List | Medium | Two Pointers | Amazon, Google |
| 39 | Copy List with Random Pointer | Medium | Hash Map, Cloning | Meta, Amazon |
| 40 | Add Two Numbers | Medium | Simulation | Meta, Amazon |
| 41 | Linked List Cycle | Easy | Floyd's Algorithm | All FAANG |
| 42 | Find the Duplicate Number | Medium | Floyd's Algorithm | All FAANG |
| 43 | LRU Cache | Medium | Design, Hash Map | All FAANG |
| 44 | Merge k Sorted Lists | Hard | Divide & Conquer | All FAANG |
| 45 | Reverse Nodes in k-Group | Hard | Advanced Reversal | Meta, Google |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 46 | Invert Binary Tree | Easy | DFS/BFS | All FAANG |
| 47 | Maximum Depth of Binary Tree | Easy | DFS/BFS | All FAANG |
| 48 | Diameter of Binary Tree | Easy | DFS | All FAANG |
| 49 | Balanced Binary Tree | Easy | DFS | Amazon, Apple |
| 50 | Same Tree | Easy | DFS/BFS | All FAANG |
| 51 | Subtree of Another Tree | Easy | DFS | Amazon, Meta |
| 52 | Lowest Common Ancestor of a Binary Search Tree | Medium | BST Property | All FAANG |
| 53 | Binary Tree Level Order Traversal | Medium | BFS | All FAANG |
| 54 | Binary Tree Right Side View | Medium | BFS/DFS | Amazon, Meta |
| 55 | Count Good Nodes in Binary Tree | Medium | DFS | Amazon, Google |
| 56 | Validate Binary Search Tree | Medium | DFS, BST | All FAANG |
| 57 | Kth Smallest Element in a BST | Medium | Inorder Traversal | All FAANG |
| 58 | Construct Binary Tree from Preorder and Inorder Traversal | Medium | Tree Construction | All FAANG |
| 59 | Binary Tree Maximum Path Sum | Hard | DFS, Path Sum | All FAANG |
| 60 | Serialize and Deserialize Binary Tree | Hard | Tree Serialization | All FAANG |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 61 | Implement Trie (Prefix Tree) | Medium | Trie Design | All FAANG |
| 62 | Design Add and Search Words Data Structure | Medium | Trie, Backtracking | Google, Meta |
| 63 | Word Search II | Hard | Trie, Backtracking | All FAANG |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 64 | Kth Largest Element in a Stream | Easy | Min Heap | All FAANG |
| 65 | Last Stone Weight | Easy | Max Heap | Amazon, Apple |
| 66 | K Closest Points to Origin | Medium | Min Heap | All FAANG |
| 67 | Kth Largest Element in an Array | Medium | Quickselect, Heap | All FAANG |
| 68 | Task Scheduler | Medium | Max Heap, Greedy | All FAANG |
| 69 | Design Twitter | Medium | Heap, Design | Amazon, Meta |
| 70 | Find Median from Data Stream | Hard | Two Heaps | All FAANG |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 71 | Subsets | Medium | Backtracking | All FAANG |
| 72 | Combination Sum | Medium | Backtracking | All FAANG |
| 73 | Permutations | Medium | Backtracking | All FAANG |
| 74 | Subsets II | Medium | Backtracking, Duplicates | Amazon, Meta |
| 75 | Combination Sum II | Medium | Backtracking, Duplicates | Amazon, Google |
| 76 | Word Search | Medium | Backtracking, Matrix | All FAANG |
| 77 | Palindrome Partitioning | Medium | Backtracking, String | Amazon, Google |
| 78 | Letter Combinations of a Phone Number | Medium | Backtracking | All FAANG |
| 79 | N-Queens | Hard | Backtracking | Google, Amazon |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 80 | Number of Islands | Medium | DFS/BFS | All FAANG |
| 81 | Clone Graph | Medium | DFS/BFS, Cloning | All FAANG |
| 82 | Max Area of Island | Medium | DFS | Amazon, Google |
| 83 | Pacific Atlantic Water Flow | Medium | DFS/BFS | Google, Amazon |
| 84 | Surrounded Regions | Medium | DFS/BFS | Amazon, Google |
| 85 | Rotting Oranges | Medium | BFS | Amazon, Apple |
| 86 | Walls and Gates | Medium | BFS | Google, Meta |
| 87 | Course Schedule | Medium | Topological Sort | All FAANG |
| 88 | Course Schedule II | Medium | Topological Sort | All FAANG |
| 89 | Redundant Connection | Medium | Union Find | Google, Amazon |
| 90 | Number of Connected Components in an Undirected Graph | Medium | Union Find/DFS | Google, Meta |
| 91 | Graph Valid Tree | Medium | Union Find/DFS | Google, Meta |
| 92 | Word Ladder | Hard | BFS | All FAANG |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 93 | Reconstruct Itinerary | Hard | Eulerian Path | Google, Amazon |
| 94 | Min Cost to Connect All Points | Medium | MST (Prim's/Kruskal's) | Amazon, Google |
| 95 | Network Delay Time | Medium | Dijkstra's Algorithm | Amazon, Google |
| 96 | Swim in Rising Water | Hard | Dijkstra's/Binary Search | Google, Amazon |
| 97 | Alien Dictionary | Hard | Topological Sort | Google, Meta |
| 98 | Cheapest Flights Within K Stops | Medium | Bellman-Ford/Dijkstra's | Google, Amazon |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 99 | Climbing Stairs | Easy | Basic DP | All FAANG |
| 100 | Min Cost Climbing Stairs | Easy | Basic DP | Amazon, Apple |
| 101 | House Robber | Medium | Linear DP | All FAANG |
| 102 | House Robber II | Medium | Circular Array DP | All FAANG |
| 103 | Longest Palindromic Substring | Medium | String DP | All FAANG |
| 104 | Palindromic Substrings | Medium | String DP | Amazon, Google |
| 105 | Decode Ways | Medium | String DP | All FAANG |
| 106 | Coin Change | Medium | DP, Greedy | All FAANG |
| 107 | Maximum Product Subarray | Medium | DP | All FAANG |
| 108 | Word Break | Medium | String DP | All FAANG |
| 109 | Longest Increasing Subsequence | Medium | DP, Binary Search | All FAANG |
| 110 | Partition Equal Subset Sum | Medium | Subset Sum DP | Amazon, Google |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 111 | Unique Paths | Medium | Grid DP | All FAANG |
| 112 | Longest Common Subsequence | Medium | String DP | All FAANG |
| 113 | Best Time to Buy and Sell Stock with Cooldown | Medium | State Machine DP | Google, Amazon |
| 114 | Coin Change 2 | Medium | Unbounded Knapsack | Amazon, Google |
| 115 | Target Sum | Medium | Subset Sum DP | Google, Meta |
| 116 | Interleaving String | Medium | String DP | Google, Amazon |
| 117 | Longest Increasing Path in a Matrix | Hard | DFS + Memoization | Google, Amazon |
| 118 | Distinct Subsequences | Hard | String DP | Google, Amazon |
| 119 | Edit Distance | Hard | String DP | Google, Meta |
| 120 | Burst Balloons | Hard | Interval DP | Google, Amazon |
| 121 | Regular Expression Matching | Hard | String DP | All FAANG |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 122 | Maximum Subarray | Medium | Kadane's Algorithm | All FAANG |
| 123 | Jump Game | Medium | Greedy | All FAANG |
| 124 | Jump Game II | Medium | Greedy | All FAANG |
| 125 | Gas Station | Medium | Greedy | Amazon, Google |
| 126 | Hand of Straights | Medium | Greedy, Hash Map | Google, Amazon |
| 127 | Merge Triplets to Form Target Triplet | Medium | Greedy | Google, Amazon |
| 128 | Partition Labels | Medium | Greedy | Amazon, Google |
| 129 | Valid Parenthesis String | Medium | Greedy | Google, Meta |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 130 | Insert Interval | Medium | Interval Merge | All FAANG |
| 131 | Merge Intervals | Medium | Interval Merge | All FAANG |
| 132 | Non-overlapping Intervals | Medium | Greedy | Amazon, Google |
| 133 | Meeting Rooms | Easy | Sorting | All FAANG |
| 134 | Meeting Rooms II | Medium | Heap, Greedy | All FAANG |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 135 | Rotate Image | Medium | Matrix Manipulation | All FAANG |
| 136 | Spiral Matrix | Medium | Matrix Traversal | All FAANG |
| 137 | Set Matrix Zeroes | Medium | Matrix Modification | Amazon, Apple |
| 138 | Happy Number | Easy | Number Theory | Google, Apple |
| 139 | Plus One | Easy | Array Manipulation | Google, Apple |
| 140 | Pow(x, n) | Medium | Fast Exponentiation | All FAANG |
| 141 | Multiply Strings | Medium | String Math | Google, Meta |
| 142 | Detect Squares | Medium | Geometry | Google, Amazon |
| No. | Problem | Difficulty | Pattern | Company Tags |
|---|---|---|---|---|
| 143 | Single Number | Easy | XOR | All FAANG |
| 144 | Number of 1 Bits | Easy | Bit Counting | All FAANG |
| 145 | Counting Bits | Easy | DP + Bits | All FAANG |
| 146 | Reverse Bits | Easy | Bit Reversal | Apple, Amazon |
| 147 | Missing Number | Easy | XOR/Math | All FAANG |
| 148 | Sum of Two Integers | Medium | Bit Arithmetic | Apple, Amazon |
| 149 | Reverse Integer | Medium | Integer Manipulation | All FAANG |
- Master basic patterns with arrays and strings
- Focus on understanding time/space complexity
- Practice implementation without looking at solutions
- Learn fundamental data structure operations
- Practice traversal algorithms (DFS, BFS)
- Understand when to use each data structure
- Study complex algorithmic patterns
- Practice problem decomposition
- Learn to identify pattern similarities
- Start with 1D DP problems
- Progress to 2D DP and advanced techniques
- Focus on state transition understanding
- Complete remaining categories
- Review challenging problems
- Take timed practice sessions
- Understand Patterns: Don't just memorize solutions - understand the underlying patterns
- Time Yourself: Practice under time constraints (20-30 minutes per problem)
- Code Without IDE: Practice writing code on paper or whiteboard
- Explain Solutions: Be able to articulate your approach and trade-offs
- Review Regularly: Revisit problems you found challenging
- Mock Interviews: Practice explaining your solution process
- NeetCode YouTube Channel: Detailed video explanations
- NeetCode.io Practice: Interactive problem solving
- LeetCode Study Plan: Official NeetCode 150 list
- Pattern-Based Learning: Algorithm patterns roadmap
Happy Coding! 🚀
Remember: Consistency beats intensity. Practice a few problems daily rather than cramming everything at once.