2324 problems
| Problem | Difficulty | Frequency ↓ | Topics |
|---|---|---|---|
| Binary Search Tree Iterator | Medium | 29.1% | TopicsStackTreeDesignBinary Search TreeBinary TreeIterator |
| Flatten Nested List Iterator | Medium | 29.1% | TopicsStackTreeDepth-First SearchDesignQueueIterator |
| Island Perimeter | Easy | 29.1% | TopicsArrayDepth-First SearchBreadth-First SearchMatrix |
| Two Sum IV - Input is a BST | Easy | 29.1% | TopicsHash TableTwo PointersTreeDepth-First SearchBreadth-First SearchBinary Search TreeBinary Tree |
| 832. Flipping an Image | Easy | 29.1% | TopicsArrayTwo PointersBit ManipulationMatrixSimulation |
| 867. Transpose Matrix | Easy | 29.1% | TopicsArrayMatrixSimulation |
| 1781. Sum of Beauty of All Substrings | Medium | 29.1% | TopicsHash TableStringCounting |
| 3346. Maximum Frequency of an Element After Performing Operations I | Medium | 29.1% | TopicsArrayBinary SearchSliding WindowSortingPrefix Sum |
| Spiral Matrix II | Medium | 28.3% | TopicsArrayMatrixSimulation |
| Number of Digit One | Hard | 28.3% | TopicsMathDynamic ProgrammingRecursion |
| 235. Lowest Common Ancestor of a Binary Search Tree | Medium | 28.3% | TopicsTreeDepth-First SearchBinary Search TreeBinary TreeBinary LiftingLowest Common Ancestor |
| 261. Graph Valid Tree | Medium | 28.3% | TopicsDepth-First SearchBreadth-First SearchUnion-FindGraph Theory |
| Binary Tree Vertical Order Traversal | Medium | 28.3% | TopicsHash TableTreeDepth-First SearchBreadth-First SearchSortingBinary Tree |
| Android Unlock Patterns | Medium | 28.3% | TopicsDynamic ProgrammingBacktrackingBit ManipulationBitmask |
| Count Numbers with Unique Digits | Medium | 28.3% | TopicsMathDynamic ProgrammingBacktracking |
| Minimum Absolute Difference in BST | Easy | 28.3% | TopicsTreeDepth-First SearchBreadth-First SearchBinary Search TreeBinary Tree |
| 769. Max Chunks To Make Sorted | Medium | 28.3% | TopicsArrayStackGreedySortingMonotonic Stack |
| 863. All Nodes Distance K in Binary Tree | Medium | 28.3% | TopicsHash TableTreeDepth-First SearchBreadth-First SearchBinary Tree |
| 921. Minimum Add to Make Parentheses Valid | Medium | 28.3% | TopicsStringStackGreedyBracket Sequences |
| 1161. Maximum Level Sum of a Binary Tree | Medium | 28.3% | TopicsTreeDepth-First SearchBreadth-First SearchBinary Tree |
| 1081. Smallest Subsequence of Distinct Characters | Medium | 28.3% | TopicsStringStackGreedyMonotonic Stack |
| 1483. Kth Ancestor of a Tree Node | Hard | 28.3% | TopicsBinary SearchDynamic ProgrammingBit ManipulationTreeDepth-First SearchBreadth-First SearchDesignBinary Lifting |
| 1358. Number of Substrings Containing All Three Characters | Medium | 28.3% | TopicsHash TableStringSliding Window |
| 1920. Build Array from Permutation | Easy | 28.3% | TopicsArraySimulation |
| 3217. Delete Nodes From Linked List Present in Array | Medium | 28.3% | TopicsArrayHash TableLinked List |
