- R.I.P. to my old Leetcode repository, where there were
5.7k+stars and2.2k+forks (ever the top 3 in the field). - Since free questions may be even mistakenly taken down by some companies, only solutions will be post on now.
- There are new LeetCode questions every week. I'll keep updating for full summary and better solutions.
- For more problem solutions, you can see my LintCode repository.
- For more challenging problem solutions, you can also see my
GoogleCodeJam,FacebookHackerCuprepositories. - Hope you enjoy the journey of learning data structures and algorithms.
- Notes: "🔒" means your subscription of LeetCode premium membership is required for reading the question.
- Bit Manipulation
- Array
- String
- Linked List
- Stack
- Queue
- Heap
- Tree
- Hash Table
- Math
- Two Pointers
- Sort
- Recursion
- Binary Search
- Binary Search Tree
- Breadth-First Search
- Depth-First Search
- Backtracking
- Dynamic Programming
- Greedy
- Graph
- Geometry
- Simulation
- Design
- Concurrency
- C++
- Python
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0239 | Sliding Window Maximum | C++ Python | O(n) | O(k) | Hard | EPI, LintCode | |
| 0281 | Zigzag Iterator | C++ Python | O(n) | O(k) | Medium | 🔒 | |
| 0346 | Moving Average from Data Stream | C++ Python | O(1) | O(w) | Easy | 🔒 | |
| 0862 | Shortest Subarray with Sum at Least K | C++ Python | O(n) | O(n) | Hard | ||
| 0933 | Number of Recent Calls | C++ Python | O(1) on average | O(w) | Easy |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0264 | Ugly Number II | C++ Python | O(n) | O(1) | Medium | CTCI, LintCode | BST, Heap |
| 0295 | Find Median from Data Stream | C++ Python | O(nlogn) | O(n) | Hard | EPI, LintCode | BST, Heap |
| 0313 | Super Ugly Number | C++ Python | O(n * k) | O(n + k) | Medium | BST, Heap | |
| 0358 | Rearrange String k Distance Apart | C++ Python | O(n) | O(n) | Hard | 🔒 | Greedy, Heap |
| 0373 | Find K Pairs with Smallest Sums | C++ Python | O(k * log(min(n, m, k))) | O(min(n, m, k)) | Medium | ||
| 0378 | Kth Smallest Element in a Sorted Matrix | C++ Python | O(k * log(min(n, m, k))) | O(min(n, m, k)) | Medium | LintCode | |
| 0407 | Trapping Rain Water II | C++ Python | O(m * n * (logm + logn)) | O(m * n) | Hard | LintCode | |
| 0632 | Smallest Range | C++ Python | O(nlogk) | O(k) | Hard | ||
| 0703 | Kth Largest Element in a Stream | C++ Python | O(nlogk) | O(k) | Easy | ||
| 0846 | Hand of Straights | C++ Python | O(nlogn) | O(n) | Medium | ||
| 0855 | Exam Room | C++ Python | seat: O(logn) leave: O(logn) |
O(n) | Medium | BST, Hash | |
| 0857 | Minimum Cost to Hire K Workers | C++ Python | O(nlogn) | O(n) | Hard | Sort | |
| 0871 | Minimum Number of Refueling Stops | C++ Python | O(nlogn) | O(n) | Hard | Sort | |
| 1046 | Last Stone Weight | C++ Python | O(nlogn) | O(n) | Easy | ||
| 1057 | Campus Bikes | C++ Python | O((w * b) * log(w * b)) | O(w * b) | Medium | 🔒 |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0056 | Merge Intervals | C++ Python | O(nlogn) | O(1) | Hard | ||
| 0057 | Insert Interval | C++ Python | O(n) | O(1) | Hard | ||
| 0075 | Sort Colors | C++ Python | O(n) | O(1) | Medium | Tri Partition | |
| 0088 | Merge Sorted Array | C++ Python | O(n) | O(1) | Easy | ||
| 0147 | Insertion Sort List | C++ Python | O(n^2) | O(1) | Medium | ||
| 0148 | Sort List | C++ Python | O(nlogn) | O(logn) | Medium | ||
| 0164 | Maximum Gap | C++ Python | O(n) | O(n) | Hard | Tricky | |
| 0179 | Largest Number | C++ Python | O(nlogn) | O(1) | Medium | ||
| 0218 | The Skyline Problem | C++ Python | O(nlogn) | O(n) | Hard | Sort, BST | |
| 0252 | Meeting Rooms | C++ Python | O(nlogn) | O(n) | Easy | 🔒 | |
| 0253 | Meeting Rooms II | C++ Python | O(nlogn) | O(n) | Medium | 🔒 | |
| 0274 | H-Index | C++ Python | O(n) | O(n) | Medium | Counting Sort | |
| 0280 | Wiggle Sort | C++ Python | O(n) | O(1) | Medium | 🔒 | |
| 0324 | Wiggle Sort II | C++ Python | O(n) on average | O(1) | Medium | variant of Sort Colors | Tri Partition |
| 0347 | Top K Frequent Elements | C++ Python | O(n) | O(n) | Medium | Quick Select, Heap, Bucket Sort | |
| 0406 | Queue Reconstruction by Height | C++ Python | O(n * sqrt(n)) | O(n) | Medium | Tricky | |
| 0451 | Sort Characters By Frequency | C++ Python | O(n) | O(n) | Medium | ||
| 0692 | Top K Frequent Words | C++ Python | O(n + klogk) on average | O(n) | Medium | Quick Select, Heap, Bucket Sort | |
| 0912 | Sort an Array | C++ Python | O(nlogn) | O(n) | Medium | Merge Sort, Quick Sort | |
| 0937 | Reorder Log Files | C++ Python | O(nlogn * l) | O(l) | Easy | ||
| 0969 | Pancake Sorting | C++ Python | O(n^2) | O(l) | Medium | ||
| 0973 | K Closest Points to Origin | C++ Python | O(n) on average | O(1) | Easy | Quick Select, Heap | |
| 0976 | Largest Perimeter Triangle | C++ Python | O(nlogn) | O(1) | Easy | ||
| 1054 | Distant Barcodes | C++ Python | O(klogk) | O(k) | Medium | variant of Rearrange String k Distance Apart | |
| 1086 | High Five | C++ Python | O(nlogn) | O(n) | Easy | 🔒 | |
| 1094 | Car Pooling | C++ Python | O(nlogn) | O(n) | Medium | variant of Meeting Rooms II | |
| 1122 | Relative Sort Array | C++ Python | O(nlogn) | O(n) | Easy | ||
| 1229 | Meeting Scheduler | C++ Python | O(nlogn) | O(n) | Medium | Line Sweep, Heap |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0220 | Contains Duplicate III | C++ Python | O(nlogk) | O(k) | Medium | ||
| 0230 | Kth Smallest Element in a BST | C++ Python | O(max(h, k)) | O(min(h, k)) | Medium | ||
| 0235 | Lowest Common Ancestor of a Binary Search Tree | C++ Python | O(h) | O(1) | Easy | EPI | |
| 0270 | Closest Binary Search Tree Value | C++ Python | O(h) | O(1) | Easy | 🔒 | |
| 0285 | Inorder Successor in BST | C++ Python | O(h) | O(1) | Medium | 🔒 | |
| 0352 | Data Stream as Disjoint Intervals | C++ Python | O(logn) | O(n) | Hard | ||
| 0449 | Serialize and Deserialize BST | C++ Python | O(n) | O(h) | Medium | ||
| 0450 | Delete Node in a BST | C++ Python | O(h) | O(h) | Medium | ||
| 0530 | Minimum Absolute Difference in BST | C++ Python | O(n) | O(h) | Easy | ||
| 0776 | Split BST | C++ Python | O(n) | O(h) | Medium | 🔒 | |
| 0783 | Minimum Distance Between BST Nodes | C++ Python | O(n) | O(h) | Easy | ||
| 0510 | Inorder Successor in BST II | C++ Python | O(h) | O(1) | Medium | 🔒 |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0102 | Binary Tree Level Order Traversal | C++ Python | O(n) | O(n) | Easy | ||
| 0107 | Binary Tree Level Order Traversal II | C++ Python | O(n) | O(n) | Easy | ||
| 0103 | Binary Tree Zigzag Level Order Traversal | Python | O(n) | O(n) | Medium | ||
| 0117 | Populating Next Right Pointers in Each Node II | Python | O(n) | O(1) | Hard | ||
| 0127 | Word Ladder | Python | O(n * d) | O(d) | Medium | ||
| 0130 | Surrounded Regions | C++ Python | O(m * n) | O(m + n) | Medium | ||
| 0133 | Clone Graph | Python | O(n) | O(n) | Medium | ||
| 0207 | Course Schedule | Python | O(|V| + |E|) | O(|E|) | Medium | Topological Sort | |
| 0210 | Course Schedule II | Python | O(|V| + |E|) | O(|E|) | Medium | Topological Sort | |
| 0261 | Graph Valid Tree | C++ Python | O(|V| + |E|) | O(|V| + |E|) | Medium | 🔒 | |
| 0269 | Alien Dictionary | C++ Python | O(n) | O(1) | Hard | 🔒 | Topological Sort, BFS, DFS |
| 0286 | Walls and Gates | C++ Python | O(m * n) | O(g) | Medium | 🔒 | |
| 0310 | Minimum Height Trees | C++ Python | O(n) | O(n) | Medium | ||
| 0317 | Shortest Distance from All Buildings | C++ Python | O(k * m * n) | O(m * n) | Hard | 🔒 | |
| 0433 | Minimum Genetic Mutation | C++ Python | O(n * b) | O(b) | Medium | ||
| 0444 | Sequence Reconstruction | C++ Python | O(n * s) | O(n) | Medium | 🔒 | Topological Sort |
| 0490 | The Maze | C++ Python | O(max(r, c) * w) | O(w) | Medium | ||
| 0499 | The Maze III | C++ Python | O(max(r, c) * wlogw) | O(w^2) | Hard | ||
| 0505 | The Maze II | C++ Python | O(max(r, c) * wlogw) | O(w) | Medium | ||
| 0542 | 01 Matrix | C++ Python | O(m * n) | O(m * n) | Medium | DP | |
| 0666 | Path Sum IV | C++ Python | O(n) | O(w) | Medium | 🔒 | Topological Sort |
| 0675 | Cut Off Trees for Golf Event | C++ Python | O(t * m * n) | O(m * n) | Hard | A* Search Algorithm |
|
| 0742 | Closest Leaf in a Binary Tree | C++ Python | O(n) | O(n) | Medium | ||
| 0743 | Network Delay Time | C++ Python | O(|E| * log|V|) | O(|E|) | Medium | Dijkstra's algorithm |
|
| 0752 | Open the Lock | C++ Python | O(k * n^k + d) | O(k * n^k + d) | Medium | ||
| 0773 | Sliding Puzzle | C++ Python | O((m * n) * (m * n)!) | O((m * n) * (m * n)!) | Hard | A* Search Algorithm |
|
| 0787 | Cheapest Flights Within K Stops | C++ Python | O(|E| * log|V|) | O(|E|) | Medium | Dijkstra's algorithm |
|
| 0815 | Bus Routes | C++ Python | O(|E| + |V|) | O(|E| + |V|) | Hard | ||
| 0854 | K-Similar Strings | C++ Python | O(n * n!/(c_a!*...*c_z!)) | O(n * n!/(c_a!*...*c_z!)) | Hard | ||
| 0865 | Shortest Path to Get All Keys | C++ Python | O(k * r * c + k^3*2^k) | O(k*2^k) | Hard | Dijkstra's algorithm |
|
| 0882 | Reachable Nodes In Subdivided Graph | C++ Python | O(|E| * log|V|) | O(|E|) | Hard | Dijkstra's algorithm |
|
| 0886 | Possible Bipartition | C++ Python | O(|V| + |E|) | O(|V| + |E|) | Medium | ||
| 0934 | Shortest Bridge | C++ Python | O(n^2) | O(n^2) | Medium | BFS, DFS | |
| 0967 | Numbers With Same Consecutive Differences | C++ Python | O(2^n) | O(2^n) | Medium | ||
| 0994 | Rotting Oranges | C++ Python | O(m * n) | O(m * n) | Easy | ||
| 1034 | Coloring A Border | C++ Python | O(m * n) | O(m + n) | Medium | ||
| 1036 | Escape a Large Maze | C++ Python | O(n^2) | O(n) | Hard | ||
| 1091 | Shortest Path in Binary Matrix | C++ Python | O(n^2) | O(n) | Medium | ||
| 1102 | Path With Maximum Minimum Value | C++ Python | O((m * n) * log(m * n)) | O(m * n) | Medium | 🔒 | Binary Search, DFS, Dijkstra's algorithm |
| 1129 | Shortest Path with Alternating Colors | C++ Python | O(n + e) | O(n + e) | Medium | ||
| 1136 | Parallel Courses | C++ Python | O(|V| + |E|) | O(|E|) | Hard | 🔒 | Topological Sort |
| 1161 | Maximum Level Sum of a Binary Tree | C++ Python | O(n) | O(w) | Medium | DFS | |
| 1162 | As Far from Land as Possible | C++ Python | O(m * n) | O(m * n) | Medium | ||
| 1163 | Last Substring in Lexicographical Order | C++ Python | O(n) | O(n) | Hard | ||
| 1203 | Sort Items by Groups Respecting Dependencies | C++ Python | O(n + e) | O(n + e) | Hard | Topological Sort | |
| 1210 | Minimum Moves to Reach Target with Rotations | C++ Python | O(n) | O(n) | Hard | ||
| 1215 | Stepping Numbers | C++ Python | O(logk + r) | O(k) | Medium | 🔒 | Precompute, Binary Search |
| 1245 | Tree Diameter | C++ Python | O(|V| + |E|) | O(|E|) | Medium |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0112 | Path Sum | Python | O(n) | O(h) | Easy | ||
| 0113 | Path Sum II | Python | O(n) | O(h) | Medium | ||
| 0199 | Binary Tree Right Side View | Python | O(n) | O(h) | Medium | ||
| 0200 | Number of Islands | Python | O(m * n) | O(m * n) | Medium | ||
| 0236 | Lowest Common Ancestor of a Binary Tree | C++ Python | O(n) | O(h) | Medium | EPI | |
| 0247 | Strobogrammatic Number II | C++ Python | O(n^2 * 5^(n/2)) | O(n) | Medium | 🔒 | |
| 0250 | Count Univalue Subtrees | C++ Python | O(n) | O(h) | Medium | 🔒 | |
| 0257 | Binary Tree Paths | C++ Python | O(n * h) | O(h) | Easy | ||
| 0282 | Expression Add Operators | C++ Python | O(4^n) | O(n) | Hard | ||
| 0301 | Remove Invalid Parentheses | C++ Python | O(C(n, c)) | O(c) | Hard | ||
| 0329 | Longest Increasing Path in a Matrix | C++ Python | O(m * n) | O(m * n) | Hard | ||
| 0332 | Reconstruct Itinerary | C++ Python | O(t! / (n1! * n2! * ... nk!)) | O(t) | Medium | ||
| 0339 | Nested List Weight Sum | C++ Python | O(n) | O(h) | Easy | 🔒 | |
| 0364 | Nested List Weight Sum II | C++ Python | O(n) | O(h) | Medium | 🔒 | |
| 0366 | Find Leaves of Binary Tree | C++ Python | O(n) | O(h) | Medium | 🔒 | |
| 0399 | Evaluate Division | C++ Python | O(q * |V|!) | O(e) | Medium | ||
| 0417 | Pacific Atlantic Water Flow | C++ Python | O(m * n) | O(m * n) | Medium | ||
| 0440 | K-th Smallest in Lexicographical Order | C++ Python | O(logn) | O(logn) | Hard | ||
| 0464 | Can I Win | C++ Python | O(n!) | O(n) | Medium | ||
| 0515 | Find Largest Value in Each Tree Row | C++ Python | O(n) | O(h) | Medium | ||
| 0547 | Friend Circles | C++ Python | O(n^2) | O(n) | Medium | Union Find | |
| 0582 | Kill Process | C++ Python | O(n) | O(n) | Medium | 🔒 | DFS, BFS |
| 0638 | Shopping Offers | C++ Python | O(n * 2^n) | O(n) | Medium | ||
| 0690 | Employee Importance | C++ Python | O(n) | O(h) | Easy | DFS, BFS | |
| 0694 | Number of Distinct Islands | C++ Python | O(m * n) | O(m * n) | Medium | 🔒 | |
| 0695 | Max Area of Island | C++ Python | O(m * n) | O(m * n) | Easy | ||
| 0711 | Number of Distinct Islands II | C++ Python | O((m * n) * log(m * n)) | O(m * n) | Hard | 🔒 | Hash |
| 0733 | Max Area of Island | C++ Python | O(m * n) | O(m * n) | Easy | ||
| 0749 | Contain Virus | C++ Python | O((m * n)^(4/3)) | O(m * n) | Hard | Simulation | |
| 0753 | Cracking the Safe | C++ Python | O(k^n) | O(k^n) | Hard | de Bruijn sequences, Lyndon word |
|
| 0756 | Pyramid Transition Matrix | C++ Python | O(a^b) | O(a^b) | Medium | ||
| 0785 | Is Graph Bipartite? | C++ Python | O(|V| + |E|) | O(|V|) | Medium | ||
| 0797 | All Paths From Source to Target | C++ Python | O(p + r * n) | O(n) | Medium | ||
| 0802 | Find Eventual Safe States | C++ Python | O(|V| + |E|) | O(|V|) | Medium | ||
| 0827 | Making A Large Island | C++ Python | O(n^2) | O(n^2) | Hard | ||
| 0834 | Sum of Distances in Tree | C++ Python | O(n) | O(n) | Hard | ||
| 0841 | Keys and Rooms | C++ Python | O(n!) | O(n) | Medium | ||
| 0851 | Loud and Rich | C++ Python | O(q + r) | O(q + r) | Medium | ||
| 0913 | Cat and Mouse | C++ Python | O(n^3) | O(n^2) | Hard | ||
| 1020 | Number of Enclaves | C++ Python | O(m * n) | O(m * n) | Medium | ||
| 1059 | All Paths from Source Lead to Destination | C++ Python | O(n + e) | O(n + e) | Medium | 🔒 | |
| 1192 | Critical Connections in a Network | C++ Python | O(|V| + |E|) | O(|V| + |E|) | Hard | Tarjan's Algorithm, Bridge Finding Algorithm |
|
| 1202 | Smallest String With Swaps | C++ Python | O(nlogn) | O(n) | Medium | Union Find | |
| 1254 | Number of Closed Islands | C++ Python | O(m * n) | O(1) | Medium |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0017 | Letter Combinations of a Phone Number | Python | O(n * 4^n) | O(n) | Medium | ||
| 0022 | Generate Parentheses | Python | O(4^n / n^(3/2)) | O(n) | Medium | ||
| 0037 | Sudoku Solver | Python | O((9!)^9) | O(1) | Hard | ||
| 0039 | Combination Sum | Python | O(k * n^k) | O(k) | Medium | ||
| 0040 | Combination Sum II | Python | O(k * C(n, k)) | O(k) | Medium | ||
| 0046 | Permutations | Python | O(n * n!) | O(n) | Medium | ||
| 0047 | Permutations II | Python | O(n * n!) | O(n) | Medium | ||
| 0051 | N-Queens | Python | O(n!) | O(n) | Hard | ||
| 0052 | N-Queens-II | Python | O(n!) | O(n) | Hard | ||
| 0077 | Combinations | Python | O(O(k * C(n, k))) | O(k) | Medium | ||
| 0079 | Word Search | Python | O(m * n * l) | O(l) | Medium | ||
| 0093 | Restore IP Addresses | Python | O(1) | O(1) | Medium | ||
| 0078 | Subsets | C++ Python | O(n * 2^n) | O(1) | Medium | ||
| 0090 | Subsets II | C++ Python | O(n * 2^n) | O(1) | Medium | ||
| 0126 | Word Ladder II | Python | O(n * d) | O(d) | Hard | ||
| 0131 | Palindrome Partitioning | Python | O(n^2) ~ O(2^n) | O(n^2) | Medium | ||
| 0140 | Word Break II | C++ Python | O(n * l^2 + n * r) | O(n^2) | Hard | ||
| 0212 | Word Search II | C++ Python | O(m * n * l) | O(l) | Hard | LintCode | Trie, DFS |
| 0216 | Combination Sum III | C++ Python | O(k * C(n, k)) | O(k) | Medium | ||
| 0254 | Factor Combinations | C++ Python | O(nlogn) | O(logn) | Medium | 🔒 | |
| 0267 | Palindrome Permutation II | C++ Python | O(n * n!) | O(n) | Medium | 🔒 | |
| 0291 | Word Pattern II | C++ Python | O(n * C(n - 1, c - 1)) | O(n + c) | Hard | 🔒 | |
| 0294 | Flip Game II | C++ Python | O(n + c^2) | O(c) | Medium | 🔒 | DP, Hash |
| 0320 | Generalized Abbreviation | C++ Python | O(n * 2^n) | O(n) | Medium | 🔒 | |
| 0425 | Word Squares | C++ Python | O(n^2 * n!) | O(n^2) | Hard | 🔒 | |
| 0526 | Beautiful Arrangement | C++ Python | O(n!) | O(n) | Medium | ||
| 0676 | Implement Magic Dictionary | C++ Python | O(n) | O(d) | Medium | Trie, DFS | |
| 0679 | 24 Game | C++ Python | O(1) | O(1) | Hard | DFS | |
| 0698 | Partition to K Equal Sum Subsets | C++ Python | O(n * 2^n) | O(2^n) | Medium | DFS, DP, Memoization | |
| 0718 | Maximum Length of Repeated Subarray | C++ Python | O(m * n) | O(min(m, n)) | Medium | DP, Hash, Binary Search | |
| 0784 | Letter Case Permutation | C++ Python | O(n * 2^n) | O(1) | Easy | ||
| 0996 | Number of Squareful Arrays | C++ Python | O(n!) | O(n^2) | Hard | ||
| 1087 | Brace Expansion | C++ Python | O(p * l * log(p * l)) | O(p * l) | Medium | 🔒 | |
| 1096 | Brace Expansion II | C++ Python | O(p * l * log(p * l)) | O(p * l) | Hard | ||
| 1219 | Path with Maximum Gold | C++ Python | O(m^2 * n^2) | O(m * n) | Medium | ||
| 1240 | Tiling a Rectangle with the Fewest Squares | C++ Python | O(n^2 * m^2 * m^(n * m)) | O(n * m) | Hard | ||
| 1255 | Maximum Score Words Formed by Letters | C++ Python | O(n * 2^n) | O(n) | Hard |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0010 | Regular Expression Matching | Python | O(m * n) | O(n) | Hard | ||
| 0044 | Wildcard Matching | Python | O(m * n) | O(1) | Hard | Greedy | |
| 0053 | Maximum Subarray | C++ Python | O(n) | O(1) | Medium | ||
| 0062 | Unique Paths | Python | O(m * n) | O(m + n) | Medium | ||
| 0063 | Unique Paths II | Python | O(m * n) | O(m + n) | Medium | ||
| 0064 | Minimum Path Sum | Python | O(m * n) | O(m + n) | Medium | ||
| 0070 | Climbing Stairs | C++ Python | O(logn) | O(1) | Easy | Matrix Exponentiation | |
| 0072 | Edit Distance | Python | O(m * n) | O(m + n) | Hard | ||
| 0087 | Scramble String | Python | O(n^4) | O(n^3) | Hard | ||
| 0091 | Decode Ways | C++ Python | O(n) | O(1) | Medium | ||
| 0096 | Unique Binary Search Trees | Python | O(n) | O(1) | Medium | Math | |
| 0097 | Interleaving String | Python | O(m * n) | O(m + n) | Hard | ||
| 0115 | Distinct Subsequences | Python | O(n^2) | O(n) | Hard | ||
| 0120 | Triangle | Python | O(m * n) | O(n) | Medium | ||
| 0123 | Best Time to Buy and Sell Stock III | Python | O(n) | O(1) | Hard | ||
| 0132 | Palindrome Partitioning II | Python | O(n^2) | O(n^2) | Hard | ||
| 0139 | Word Break | C++ Python | O(n * l^2) | O(n) | Medium | ||
| 0152 | Maximum Product Subarray | Python | O(n) | O(1) | Medium | ||
| 0174 | Dungeon Game | Python | O(m * n) | O(m + n) | Hard | ||
| 0188 | Best Time to Buy and Sell Stock IV | Python | O(k * n) | O(k) | Hard | ||
| 0198 | House Robber | C++ Python | O(n) | O(1) | Easy | ||
| 0213 | House Robber II | C++ Python | O(n) | O(1) | Medium | ||
| 0221 | Maximal Square | C++ Python | O(n^2) | O(n) | Medium | EPI | |
| 0256 | Paint House | C++ Python | O(n) | O(1) | Medium | 🔒 | |
| 0265 | Paint House II | C++ Python | O(n * k) | O(k) | Hard | 🔒 | |
| 0276 | Paint Fence | C++ Python | O(n) | O(1) | Easy | 🔒 | |
| 0279 | Perfect Squares | C++ Python | O(n * sqrt(n)) | O(n) | Medium | Hash | |
| 0303 | Range Sum Query - Immutable | C++ Python | ctor: O(n), lookup: O(1) | O(n) | Easy | ||
| 0304 | Range Sum Query 2D - Immutable | C++ Python | ctor: O(m * n), lookup: O(1) | O(m * n) | Medium | ||
| 0309 | Best Time to Buy and Sell Stock with Cooldown | C++ Python | O(n) | O(1) | Medium | ||
| 0312 | Burst Balloons | C++ Python | O(n^3) | O(n^2) | Hard | ||
| 0322 | Coin Change | C++ Python | O(n * k) | O(k) | Medium | ||
| 0351 | Android Unlock Patterns | C++ Python | O(9^2 * 2^9) | O(9 * 2^9) | Medium | 🔒 | Backtracking |
| 0357 | Count Numbers with Unique Digits | C++ Python | O(n) | O(1) | Medium | Backtracking, Math | |
| 0361 | Bomb Enemy | C++ Python | O(m * n) | O(m * n) | Medium | 🔒 | |
| 0368 | Largest Divisible Subset | C++ Python | O(n^2) | O(n) | Medium | ||
| 0375 | Guess Number Higher or Lower II | C++ Python | O(n^2) | O(n^2) | Medium | ||
| 0377 | Combination Sum IV | C++ Python | O(nlogn + n * t) | O(t) | Medium | ||
| 0403 | Frog Jump | C++ Python | O(n^2) | O(n^2) | Hard | ||
| 0416 | Partition Equal Subset Sum | C++ Python | O(n * s) | O(s) | Medium | ||
| 0418 | Sentence Screen Fitting | C++ Python | O(r + n * c) | O(n) | Medium | 🔒 | |
| 0446 | Arithmetic Slices II - Subsequence | C++ Python | O(n^2) | O(n * d) | Hard | ||
| 0465 | Optimal Account Balancing | C++ Python | O(n * 2^n) | O(2^n) | Hard | 🔒 | |
| 0466 | Count The Repetitions | C++ Python | O(s1 * min(s2, n1)) | O(s2) | Hard | ||
| 0467 | Unique Substrings in Wraparound String | C++ Python | O(n) | O(1) | Medium | ||
| 0471 | Encode String with Shortest Length | C++ Python | O(n^3) on average | O(n^2) | Medium | 🔒 | |
| 0472 | Concatenated Words | C++ Python | O(n * l^2) | O(n * l) | Medium | ||
| 0474 | Ones and Zeroes | C++ Python | O(s * m * n) | O(m * n) | Medium | ||
| 0486 | Predict the Winner | C++ Python | O(n^2) | O(n) | Medium | ||
| 0509 | Fibonacci Number | C++ Python | O(logn) | O(1) | Easy | variant of Climbing Stairs | Matrix Exponentiation |
| 0514 | Freedom Trail | C++ Python | O(k) ~ O(k * r^2) | O(r) | Hard | ||
| 0516 | Longest Palindromic Subsequence | C++ Python | O(n^2) | O(n) | Medium | ||
| 0546 | Remove Boxes | C++ Python | O(n^3) ~ O(n^4) | O(n^3) | Hard | ||
| 0552 | Student Attendance Record II | C++ Python | O(n) | O(1) | Hard | ||
| 0562 | Longest Line of Consecutive One in Matrix | C++ Python | O(m * n) | O(n) | Medium | 🔒 | |
| 0568 | Maximum Vacation Days | C++ Python | O(n^2 * k) | O(k) | Hard | 🔒 | |
| 0576 | Out of Boundary Paths | C++ Python | O(N * m * n) | O(m * n) | Medium | ||
| 0583 | Delete Operation for Two Strings | C++ Python | O(m * n) | O(n) | Medium | ||
| 0600 | Non-negative Integers without Consecutive Ones | C++ Python | O(1) | O(1) | Hard | ||
| 0629 | K Inverse Pairs Array | C++ Python | O(n * k) | O(k) | Hard | ||
| 0639 | Decode Ways II | C++ Python | O(n) | O(1) | Hard | ||
| 0650 | 2 Keys Keyboard | C++ Python | O(sqrt(n)) | O(1) | Medium | ||
| 0656 | Coin Path | C++ Python | O(n * B) | O(n) | Hard | 🔒 | |
| 0664 | Strange Printer | C++ Python | O(n^3) | O(n^2) | Hard | ||
| 0673 | Number of Longest Increasing Subsequence | C++ Python | O(n^2) | O(n) | Medium | ||
| 0688 | Knight Probability in Chessboard | C++ Python | O(k * n^2) | O(n^2) | Medium | ||
| 0689 | Maximum Sum of 3 Non-Overlapping Subarrays | C++ Python | O(n) | O(n) | Hard | ||
| 0691 | Stickers to Spell Word | C++ Python | O(T * S^T) | O(T * S^T) | Hard | Backtracking, Memoization | |
| 0712 | Minimum ASCII Delete Sum for Two Strings | C++ Python | O(m * n) | O(n) | Medium | ||
| 0714 | Best Time to Buy and Sell Stock with Transaction Fee | C++ Python | O(n) | O(1) | Medium | ||
| 0727 | Minimum Window Subsequence | C++ Python | O(s * t) | O(s) | Hard | 🔒 | |
| 0730 | Count Different Palindromic Subsequences | C++ Python | O(n^2) | O(n) | Hard | ||
| 0740 | Delete and Earn | C++ Python | O(n) | O(1) | Medium | ||
| 0741 | Cherry Pickup | C++ Python | O(n^3) | O(n^2) | Hard | ||
| 0746 | Min Cost Climbing Stairs | C++ Python | O(n) | O(1) | Easy | ||
| 0750 | Number Of Corner Rectangles | C++ Python | O(n * m^2) | O(n * m) | Medium | ||
| 0764 | Largest Plus Sign | C++ Python | O(n^2) | O(n^2) | Medium | ||
| 0788 | Rotated Digits | C++ Python | O(logn) | O(logn) | Easy | Memoization | |
| 0790 | Domino and Tromino Tiling | C++ Python | O(logn) | O(1) | Medium | Matrix Exponentiation | |
| 0799 | Champagne Tower | C++ Python | O(n^2) | O(n) | Medium | ||
| 0801 | Minimum Swaps To Make Sequences Increasing | C++ Python | O(n) | O(1) | Medium | ||
| 0805 | Split Array With Same Average | C++ Python | O(n^4) | O(n^3) | Hard | ||
| 0808 | Soup Servings | C++ Python | O(1) | O(1) | Medium | Memoization | |
| 0813 | Largest Sum of Averages | C++ Python | O(k * n^2) | O(n) | Medium | ||
| 0818 | Race Car | C++ Python | O(nlogn) | O(n) | Hard | ||
| 0823 | Binary Trees With Factors | C++ Python | O(n^2) | O(n) | Medium | ||
| 0837 | New 21 Game | C++ Python | O(n) | O(n) | Medium | ||
| 0838 | Push Dominoes | C++ Python | O(n) | O(n) | Medium | ||
| 0847 | Shortest Path Visiting All Nodes | C++ Python | O(n *2^n) | O(n * 2^n) | Hard | BFS | |
| 0877 | Stone Game | C++ Python | O(n^2) | O(n) | Medium | variant of Predict the Winner | |
| 0879 | Profitable Schemes | C++ Python | O(n * p * g) | O(p * g) | Hard | ||
| 0903 | Valid Permutations for DI Sequence | C++ Python | O(n^2) | O(n) | Hard | ||
| 0920 | Number of Music Playlists | C++ Python | O(n * l) | O(l) | Hard | ||
| 0926 | Flip String to Monotone Increasing | C++ Python | O(n) | O(1) | Medium | ||
| 0931 | Minimum Falling Path Sum | C++ Python | O(n^2) | O(1) | Medium | ||
| 0935 | Knight Dialer | C++ Python | O(logn) | O(1) | Medium | Matrix Exponentiation | |
| 0940 | Distinct Subsequences II | C++ Python | O(n) | O(1) | Hard | ||
| 0943 | Find the Shortest Superstring | C++ Python | O(n^2 * (l^2 + 2^n)) | O(n^2) | Hard | ||
| 0956 | Tallest Billboard | C++ Python | O(n * 3^(n/2)) | O(3^(n/2)) | Hard | ||
| 0960 | Delete Columns to Make Sorted III | C++ Python | O(n * l^2) | O(l) | Hard | ||
| 0964 | Least Operators to Express Number | C++ Python | O(logn / logx) | O(logn) | Hard | Math | |
| 0975 | Odd Even Jump | C++ Python | O(nlogn) | O(n) | Hard | Mono Stack, BST | |
| 0980 | Unique Paths III | C++ Python | O((m * n) * 2^(m * n)) | O((m * n) * 2^(m * n)) | Hard | ||
| 0983 | Minimum Cost For Tickets | C++ Python | O(n) | O(1) | Medium | ||
| 1000 | Minimum Cost to Merge Stones | C++ Python | O(n^3) | O(n^3) | Hard | Memoization | |
| 1027 | Longest Arithmetic Sequence | C++ Python | O(n^2) | O(n^2) | Medium | ||
| 1035 | Uncrossed Lines | C++ Python | O(m * n) | O(min(m, n)) | Medium | ||
| 1039 | Minimum Score Triangulation of Polygon | C++ Python | O(n^3) | O(n^2) | Medium | ||
| 1043 | Partition Array for Maximum Sum | C++ Python | O(n * k) | O(k) | Medium | ||
| 1048 | Longest String Chain | C++ Python | O(n * l^2) | O(n * l) | Medium | ||
| 1049 | Last Stone Weight II | C++ Python | O(2^n) | O(2^n) | Medium | ||
| 1066 | Campus Bikes II | C++ Python | O(w * b * 2^b) | O(w * b * 2^b) | Medium | 🔒 | |
| 1092 | Shortest Common Supersequence | C++ Python | O(m * n) | O(m * n) | Hard | ||
| 1105 | Filling Bookcase Shelves | C++ Python | O(n^2) | O(n) | Medium | ||
| 1125 | Smallest Sufficient Team | C++ Python | O(m * 2^n) | O(2^n) | Hard | ||
| 1137 | N-th Tribonacci Number | C++ Python | O(logn) | O(1) | Easy | variant of Fibonacci Number | Matrix Exponentiation |
| 1139 | Largest 1-Bordered Square | C++ Python | O(n^3) | O(n^2) | Medium | ||
| 1140 | Stone Game II | C++ Python | O(n*(logn)^2) | O(nlogn) | Medium | ||
| 1143 | Longest Common Subsequence | C++ Python | O(m * n) | O(min(m, n)) | Medium | ||
| 1155 | Number of Dice Rolls With Target Sum | C++ Python | O(d * f * t) | O(t) | Medium | ||
| 1182 | Shortest Distance to Target Color | C++ Python | O(n) | O(n) | Medium | 🔒 | |
| 1186 | Maximum Subarray Sum with One Deletion | C++ Python | O(n) | O(1) | Medium | ||
| 1187 | Make Array Strictly Increasing | C++ Python | O(n^2 * logn) | O(n) | Hard | ||
| 1191 | K-Concatenation Maximum Sum | C++ Python | O(n) | O(1) | Medium | ||
| 1216 | Valid Palindrome III | C++ Python | O(n^2) | O(n) | Hard | 🔒, variant of Longest Palindromic Subsequence | |
| 1218 | Longest Arithmetic Subsequence of Given Difference | C++ Python | O(n) | O(n) | Medium | ||
| 1220 | Count Vowels Permutation | C++ Python | O(logn) | O(1) | Hard | Matrix Exponentiation | |
| 1223 | Dice Roll Simulation | C++ Python | O(m * n) | O(m) | Medium | ||
| 1230 | Toss Strange Coins | C++ Python | O(n^2) | O(n) | Medium | ||
| 1235 | Maximum Profit in Job Scheduling | C++ Python | O(nlogn) | O(n) | Hard | DP, Heap | |
| 1239 | Maximum Length of a Concatenated String with Unique Characters | C++ Python | O(n) ~ O(2^n) | O(1) ~ O(2^n) | Medium | DP, Bit Manipulation | |
| 1246 | Palindrome Removal | C++ Python | O(n^3) | O(n^2) | Hard |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0765 | Couples Holding Hands | C++ Python | O(n) | O(n) | Hard | ||
| 0924 | Minimize Malware Spread | C++ Python | O(n^2) | O(n) | Hard | Union Find | |
| 0928 | Minimize Malware Spread II | C++ Python | O(n^2) | O(n) | Hard | Union Find | |
| 0959 | Regions Cut By Slashes | C++ Python | O(n^2) | O(n^2) | Medium | Union Find | |
| 0990 | Satisfiability of Equality Equations | C++ Python | O(n) | O(1) | Medium | Union Find | |
| 1042 | Flower Planting With No Adjacent | C++ Python | O(n) | O(n) | Easy | ||
| 1101 | The Earliest Moment When Everyone Become Friends | C++ Python | O(nlogn) | O(n) | Medium | 🔒 | Union Find |
| 1135 | Connecting Cities With Minimum Cost | C++ Python | O(nlogn) | O(n) | Medium | 🔒 | Union Find, Kruskal's Algorithm, MST |
| 1168 | Optimize Water Distribution in a Village | C++ Python | O(nlogn) | O(n) | Hard | 🔒 | Union Find |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0587 | Erect the Fence | C++ Python | O(nlogn) | O(n) | Hard | Convex Hull, Monotone Chain |
|
| 0892 | Surface Area of 3D Shapes | C++ Python | O(n^2) | O(1) | Easy |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0874 | Walking Robot Simulation | C++ Python | O(n + k) | O(k) | Easy | ||
| 1138 | Alphabet Board Path | C++ Python | O(n) | O(1) | Medium | ||
| 1243 | Array Transformation | C++ Python | O(n^2) | O(n) | Easy |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0146 | LRU Cache | C++ Python | O(1) | O(k) | Hard | ||
| 0225 | Implement Stack using Queues | C++ Python | push: O(n), pop: O(1), top: O(1) | O(n) | Easy | ||
| 0284 | Peeking Iterator | C++ Python | O(1) | O(1) | Medium | ||
| 0348 | Design Tic-Tac-Toe | C++ Python | O(1) | O(n^2) | Medium | 🔒 | |
| 0353 | Design Snake Game | C++ Python | O(1) | O(s) | Medium | 🔒 | Deque |
| 0355 | Design Twitter | C++ Python | O(klogu) | O(t + f) | Medium | LintCode | Heap |
| 0359 | Logger Rate Limiter | C++ Python | O(1), amortized | O(k) | Easy | 🔒 | Deque |
| 0362 | Design Hit Counter | C++ Python | O(1), amortized | O(k) | Medium | 🔒 | Deque |
| 0379 | Design Phone Directory | C++ Python | O(1) | O(n) | Medium | 🔒 | |
| 0380 | Insert Delete GetRandom O(1) | C++ Python | O(1) | O(n) | Hard | ||
| 0381 | Insert Delete GetRandom O(1) - Duplicates allowed | C++ Python | O(1) | O(n) | Hard | ||
| 0432 | All O`one Data Structure | C++ Python | O(1) | O(n) | Hard | ||
| 0460 | LFU Cache | C++ Python | O(1) | O(k) | Hard | ||
| 0535 | Encode and Decode TinyURL | C++ Python | O(1) | O(n) | Medium | ||
| 0588 | Design In-Memory File System | C++ Python | ls: O(l + klogk) mkdir: O(l) addContentToFile: O(l + c) readContentFromFile: O(l + c) |
O(n + s) | Hard | 🔒 | |
| 0604 | Design Compressed String Iterator | C++ Python | O(1) | O(1) | Easy | 🔒 | |
| 0631 | Design Excel Sum Formula | C++ Python | set: O((r * c)^2) get: O(1) sum: O((r * c)^2) |
O(r * c) | Hard | 🔒 | |
| 0635 | Design Log Storage System | C++ Python | put: O(1) retrieve: O(n + dlogd) |
O(n) | Medium | 🔒 | |
| 0642 | Design Search Autocomplete System | C++ Python | O(p^2) | O(p * t + s) | Hard | 🔒 | |
| 0715 | Range Module | C++ Python | add: O(n) remove: O(n) query: O(logn) |
O(n) | Hard | ||
| 0716 | Max Stack | C++ Python | push: O(logn) pop: O(logn) popMax: O(logn) top: O(1) peekMax: O(1) |
O(n) | Easy | ||
| 0745 | Prefix and Suffix Search | C++ Python | ctor: O(w * l^2) search : O(p + s) |
O(t) | Hard | Trie | |
| 0900 | RLE Iterator | C++ Python | O(n) | O(1) | Medium | ||
| 1146 | Snapshot Array | C++ Python | set: O(1) get: O(logn) |
O(n) | Medium | ||
| 1166 | Design File System | C++ Python | create: O(n) get: O(n) |
O(n) | Medium | 🔒 | |
| 1172 | Dinner Plate Stacks | C++ Python | push: O(logn) pop: O(1), amortized popAtStack: (logn) |
O(n * c) | Hard | ||
| 1206 | Design Skiplist | C++ Python | O(logn), on average | O(n) | Hard | ||
| 1236 | Web Crawler | C++ Python | O(|V| + |E|) | O(|V|) | Medium | 🔒 | |
| 1244 | Design A Leaderboard | C++ Python | ctor: O(1) add: O(1) top: O(n) reset: O(1) |
O(n) | Medium |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 1114 | Print in Order | C++ Python | O(n) | O(1) | Easy | ||
| 1115 | Print FooBar Alternately | C++ Python | O(n) | O(1) | Medium | ||
| 1116 | Print Zero Even Odd | C++ Python | O(n) | O(1) | Medium | ||
| 1117 | Building H2O | C++ Python | O(n) | O(1) | Hard | ||
| 1188 | Design Bounded Blocking Queue | C++ Python | O(n) | O(1) | Medium | 🔒 | |
| 1195 | Fizz Buzz Multithreaded | C++ Python | O(n) | O(1) | Medium | ||
| 1226 | The Dining Philosophers | C++ Python | O(n) | O(1) | Medium | ||
| 1242 | Web Crawler Multithreaded | C++ Python | O(|V| + |E|) | O(|V|) | Medium | 🔒 |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0175 | Combine Two Tables | MySQL | O(m + n) | O(m + n) | Easy | ||
| 0176 | Second Highest Salary | MySQL | O(n) | O(1) | Easy | ||
| 0177 | Nth Highest Salary | MySQL | O(n^2) | O(n) | Medium | ||
| 0178 | Rank Scores | MySQL | O(n^2) | O(n) | Medium | ||
| 0180 | Consecutive Numbers | MySQL | O(n) | O(n) | Medium | ||
| 0181 | Employees Earning More Than Their Managers | MySQL | O(n^2) | O(1) | Easy | ||
| 0182 | Duplicate Emails | MySQL | O(n^2) | O(n) | Easy | ||
| 0183 | Customers Who Never Order | MySQL | O(n^2) | O(1) | Easy | ||
| 0184 | Department Highest Salary | MySQL | O(n^2) | O(n) | Medium | ||
| 0185 | Department Top Three Salaries | MySQL | O(n^2) | O(n) | Hard | ||
| 0196 | Delete Duplicate Emails | MySQL | O(n^2) | O(n) | Easy | ||
| 0197 | Rising Temperature | MySQL | O(n^2) | O(n) | Easy | ||
| 0262 | Trips and Users | MySQL | O((t * u) + tlogt) | O(t) | Hard | ||
| 0511 | Game Play Analysis I | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 0512 | Game Play Analysis II | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 0534 | Game Play Analysis III | MySQL | O(nlogn) | O(n) | Medium | 🔒 | |
| 0550 | Game Play Analysis IV | MySQL | O(n) | O(n) | Medium | 🔒 | |
| 1045 | Customers Who Bought All Products | MySQL | O(n + k) | O(n + k) | Medium | 🔒 | |
| 1050 | Actors and Directors Who Cooperated At Least Three Times | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1068 | Product Sales Analysis I | MySQL | O(m + n) | O(m + n) | Easy | 🔒 | |
| 1069 | Product Sales Analysis II | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1070 | Product Sales Analysis III | MySQL | O(n) | O(n) | Medium | 🔒 | |
| 1075 | Project Employees I | MySQL | O(m + n) | O(m + n) | Easy | 🔒 | |
| 1076 | Project Employees II | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1077 | Project Employees III | MySQL | O((m + n)^2) | O(m + n) | Medium | 🔒 | |
| 1082 | Sales Analysis I | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1083 | Sales Analysis II | MySQL | O(m + n) | O(m + n) | Easy | 🔒 | |
| 1084 | Sales Analysis III | MySQL | O(m + n) | O(m + n) | Easy | 🔒 | |
| 1097 | Game Play Analysis V | MySQL | O(n^2) | O(n) | Hard | 🔒 | |
| 1098 | Unpopular Books | MySQL | O(m + n) | O(n) | Medium | 🔒 | |
| 1107 | New Users Daily Count | MySQL | O(n) | O(n) | Medium | 🔒 | |
| 1112 | Highest Grade For Each Student | MySQL | O(nlogn) | O(n) | Medium | 🔒 | |
| 1113 | Reported Posts | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1126 | Active Businesses | MySQL | O(n) | O(n) | Medium | 🔒 | |
| 1127 | User Purchase Platform | MySQL | O(n) | O(n) | Hard | 🔒 | |
| 1132 | Reported Posts II | MySQL | O(m + n) | O(n) | Medium | 🔒 | |
| 1141 | User Activity for the Past 30 Days I | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1142 | User Activity for the Past 30 Days II | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1148 | Article Views I | MySQL | O(nlogn) | O(n) | Easy | 🔒 | |
| 1149 | Article Views II | MySQL | O(nlogn) | O(n) | Medium | 🔒 | |
| 1158 | Market Analysis I | MySQL | O(m + n) | O(m + n) | Medium | 🔒 | |
| 1159 | Market Analysis II | MySQL | O(m + n) | O(m + n) | Hard | 🔒 | |
| 1164 | Product Price at a Given Date | MySQL | O(mlogn) | O(m) | Medium | 🔒 | |
| 1173 | Immediate Food Delivery I | MySQL | O(n) | O(1) | Easy | 🔒 | |
| 1174 | Immediate Food Delivery II | MySQL | O(n) | O(m) | Medium | 🔒 | |
| 1179 | Reformat Department Table | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1193 | Monthly Transactions I | MySQL | O(n) | O(n) | Medium | 🔒 | |
| 1194 | Tournament Winners | MySQL | O(m + n + nlogn) | O(m + n) | Hard | 🔒 | |
| 1204 | Last Person to Fit in the Elevator | MySQL | O(nlogn) | O(n) | Medium | 🔒 | |
| 1205 | Monthly Transactions II | MySQL | O(n) | O(n) | Medium | 🔒 | |
| 1211 | Queries Quality and Percentage | MySQL | O(n) | O(n) | Easy | ||
| 1212 | Team Scores in Football Tournament | MySQL | O(nlogn) | O(n) | Medium | ||
| 1225 | Report Contiguous Dates | MySQL | O(nlogn) | O(n) | Hard | 🔒 | |
| 1241 | Number of Comments per Post | MySQL | O(n) | O(n) | Easy | 🔒 | |
| 1251 | Average Selling Price | MySQL | O(n) | O(n) | Easy | 🔒 |
| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
|---|---|---|---|---|---|---|---|
| 0192 | Word Frequency | Shell | O(n) | O(k) | Medium | ||
| 0193 | Valid Phone Numbers | Shell | O(n) | O(1) | Easy | ||
| 0194 | Transpose File | Shell | O(n^2) | O(n^2) | Medium | ||
| 0195 | Tenth Line | Shell | O(n) | O(1) | Easy |