171 problems
| Problem | Difficulty | Frequency ↓ | Topics |
|---|---|---|---|
| Paint House | Medium | 65.5% | TopicsArrayDynamic Programming |
| 146. LRU Cache | Medium | 64.7% | TopicsHash TableLinked ListDesignDoubly-Linked List |
| 235. Lowest Common Ancestor of a Binary Search Tree | Medium | 64.7% | TopicsTreeDepth-First SearchBinary Search TreeBinary TreeBinary LiftingLowest Common Ancestor |
| 297. Serialize and Deserialize Binary Tree | Hard | 63.9% | TopicsStringTreeDepth-First SearchBreadth-First SearchDesignBinary Tree |
| Exclusive Time of Functions | Medium | 63.9% | TopicsArrayStack |
| Lowest Common Ancestor of a Binary Tree | Medium | 63% | TopicsTreeDepth-First SearchBinary TreeBinary LiftingLowest Common Ancestor |
| Second Minimum Node In a Binary Tree | Easy | 63% | TopicsTreeDepth-First SearchBinary Tree |
| 101. Symmetric Tree | Easy | 62.1% | TopicsTreeDepth-First SearchBreadth-First SearchBinary Tree |
| 205. Isomorphic Strings | Easy | 62.1% | TopicsHash TableString |
| Closest Binary Search Tree Value II | Hard | 62.1% | TopicsTwo PointersStackTreeDepth-First SearchBinary Search TreeHeap (Priority Queue)Binary Tree |
| Insert Delete GetRandom O(1) - Duplicates allowed | Hard | 62.1% | TopicsArrayHash TableMathDesignRandomized |
| 215. Kth Largest Element in an Array | Medium | 61.2% | TopicsArrayDivide and ConquerSortingHeap (Priority Queue)Quickselect |
| 744. Find Smallest Letter Greater Than Target | Easy | 61.2% | TopicsArrayBinary Search |
| Random Pick with Weight | Medium | 61.2% | TopicsArrayMathBinary SearchPrefix SumRandomized |
| Shortest Word Distance | Easy | 60.1% | TopicsArrayString |
| Design Bounded Blocking Queue | Medium | 60.1% | TopicsConcurrency |
| Repeated DNA Sequences | Medium | 59.1% | TopicsHash TableStringBit ManipulationSliding WindowRolling HashHash FunctionZ AlgorithmBoyer–Moore String-Search Algorithm |
| 56. Merge Intervals | Medium | 58% | TopicsArraySortingQuicksort |
| Lowest Common Ancestor of a Binary Tree III | Medium | 58% | TopicsHash TableTwo PointersTreeBinary TreeBinary LiftingLowest Common Ancestor |
| 46. Permutations | Medium | 56.8% | TopicsArrayBacktracking |
| Valid Number | Hard | 56.8% | TopicsString |
| Max Points on a Line | Hard | 56.8% | TopicsArrayHash TableMathGeometryEuclidean AlgorithmGreatest Common Divisor |
| Factor Combinations | Medium | 56.8% | TopicsBacktrackingPrime Factorization |
| 2276. Count Integers in Intervals | Hard | 56.8% | TopicsDesignSegment TreeOrdered Set |
| Longest Palindromic Subsequence | Medium | 56.8% | TopicsStringDynamic Programming |
