2324 problems
| Problem | Difficulty | Frequency ↓ | Topics |
|---|---|---|---|
| 417. Pacific Atlantic Water Flow | Medium | 42.2% | TopicsArrayDepth-First SearchBreadth-First SearchMatrix |
| 493. Reverse Pairs | Hard | 42.2% | TopicsArrayBinary SearchDivide and ConquerBinary Indexed TreeSegment TreeMerge SortOrdered SetTreap |
| Wildcard Matching | Hard | 41.9% | TopicsStringDynamic ProgrammingGreedyRecursion |
| 74. Search a 2D Matrix | Medium | 41.9% | TopicsArrayBinary SearchMatrix |
| 101. Symmetric Tree | Easy | 41.9% | TopicsTreeDepth-First SearchBreadth-First SearchBinary Tree |
| Longest Valid Parentheses | Hard | 41.9% | TopicsStringDynamic ProgrammingStackBracket Sequences |
| Search a 2D Matrix II | Medium | 41.9% | TopicsArrayBinary SearchDivide and ConquerMatrix |
| 127. Word Ladder | Hard | 41.5% | TopicsHash TableStringBreadth-First SearchBidirectional Search |
| Lowest Common Ancestor of a Binary Tree | Medium | 41.5% | TopicsTreeDepth-First SearchBinary TreeBinary LiftingLowest Common Ancestor |
| 389. Find the Difference | Easy | 41.2% | TopicsHash TableStringBit ManipulationSorting |
| 494. Target Sum | Medium | 41.2% | TopicsArrayDynamic ProgrammingBacktrackingKnapsack Problem0-1 Knapsack |
| Remove Duplicates from Sorted List | Easy | 41.2% | TopicsLinked List |
| Create a DataFrame from List | Easy | 41.2% | Topics— |
| 1071. Greatest Common Divisor of Strings | Easy | 41.2% | TopicsMathStringEuclidean AlgorithmGreatest Common Divisor |
| 230. Kth Smallest Element in a BST | Medium | 40.8% | TopicsTreeDepth-First SearchBinary Search TreeBinary Tree |
| Remove Duplicates from Sorted Array II | Medium | 40.8% | TopicsArrayTwo Pointers |
| 278. First Bad Version | Easy | 40.8% | TopicsBinary SearchInteractive |
| 2402. Meeting Rooms III | Hard | 40.8% | TopicsArrayHash TableSortingHeap (Priority Queue)Simulation |
| Big Countries | Easy | 40.8% | TopicsDatabase |
| 621. Task Scheduler | Medium | 40.8% | TopicsArrayHash TableGreedySortingHeap (Priority Queue)Counting |
| 778. Swim in Rising Water | Hard | 40.8% | TopicsArrayBinary SearchDepth-First SearchBreadth-First SearchUnion-FindMinimaxHeap (Priority Queue)MatrixDijkstra's Algorithm |
| 130. Surrounded Regions | Medium | 40.4% | TopicsArrayDepth-First SearchBreadth-First SearchUnion-FindMatrix |
| 143. Reorder List | Medium | 40.4% | TopicsLinked ListTwo PointersStackRecursion |
| 226. Invert Binary Tree | Easy | 40.4% | TopicsTreeDepth-First SearchBreadth-First SearchBinary Tree |
| Majority Element II | Medium | 40.4% | TopicsArrayHash TableSortingCountingBoyer–Moore Majority Vote Algorithm |
