Citadel
75 problems
| Problem | Difficulty | Frequency ↓ | Topics |
|---|---|---|---|
| 2598. Smallest Missing Non-negative Integer After Operations | Medium | 69.4% | TopicsArrayHash TableMathGreedy |
| 124. Binary Tree Maximum Path Sum | Hard | 63.9% | TopicsDynamic ProgrammingTreeDepth-First SearchBinary TreeDP on Trees |
| 200. Number of Islands | Medium | 63.9% | TopicsArrayDepth-First SearchBreadth-First SearchUnion-FindMatrix |
| 287. Find the Duplicate Number | Medium | 63.9% | TopicsArrayTwo PointersBinary SearchBit ManipulationPigeonhole PrincipleFloyd's Cycle Finding Algorithm |
| Sqrt(x) | Easy | 63.9% | TopicsMathBinary SearchNewton's Method |
| 332. Reconstruct Itinerary | Hard | 63.9% | TopicsArrayStringDepth-First SearchGraph TheorySortingHeap (Priority Queue)Eulerian CircuitEulerian PathSemi-Eulerian Graph |
| 1004. Max Consecutive Ones III | Medium | 63.9% | TopicsArrayBinary SearchSliding WindowPrefix Sum |
| 127. Word Ladder | Hard | 63.9% | TopicsHash TableStringBreadth-First SearchBidirectional Search |
| 465. Optimal Account Balancing | Hard | 63.9% | TopicsArrayDynamic ProgrammingBacktrackingBit ManipulationBitmask |
| Design Tic-Tac-Toe | Medium | 63.9% | TopicsArrayHash TableDesignMatrixSimulation |
| 1. Two Sum | Easy | 63.9% | TopicsArrayHash Table |
| 23. Merge k Sorted Lists | Hard | 56.7% | TopicsLinked ListDivide and ConquerHeap (Priority Queue)Merge SortTournament Sort |
| 37. Sudoku Solver | Hard | 56.7% | TopicsArrayHash TableBacktrackingMatrixAlgorithm XDancing Links |
| 297. Serialize and Deserialize Binary Tree | Hard | 56.7% | TopicsStringTreeDepth-First SearchBreadth-First SearchDesignBinary Tree |
| 1268. Search Suggestions System | Medium | 56.7% | TopicsArrayStringBinary SearchTrieSortingHeap (Priority Queue) |
| 765. Couples Holding Hands | Hard | 56.7% | TopicsGreedyDepth-First SearchBreadth-First SearchUnion-FindGraph Theory |
| Paint House | Medium | 56.7% | TopicsArrayDynamic Programming |
| 1632. Rank Transform of a Matrix | Hard | 56.7% | TopicsArrayUnion-FindGraph TheoryTopological SortSortingMatrix |
| 103. Binary Tree Zigzag Level Order Traversal | Medium | 56.7% | TopicsTreeBreadth-First SearchBinary Tree |
| Meeting Rooms II | Medium | 56.7% | TopicsArrayTwo PointersGreedySortingHeap (Priority Queue)Prefix Sum |
| 53. Maximum Subarray | Medium | 56.7% | TopicsArrayDivide and ConquerDynamic Programming |
| Design In-Memory File System | Hard | 56.7% | TopicsHash TableStringDesignTrieSorting |
| 42. Trapping Rain Water | Hard | 56.7% | TopicsArrayTwo PointersDynamic ProgrammingStackMonotonic Stack |
| 39. Combination Sum | Medium | 46.8% | TopicsArrayBacktracking |
| 46. Permutations | Medium | 46.8% | TopicsArrayBacktracking |
