Problems
Callback's own problems and the LeetCode questions companies have been asking, in one place — pick a category, then filter by company, frequency, status, difficulty, topic, and language.
Asked on LeetCode
3,115 questions · all time
- Meeting Rooms IIIhardArrayHash TableSortingHeap (Priority Queue)+19 companies
- Design HashMapeasyArrayHash TableLinked ListDesign+19 companies
- Count Binary SubstringseasyTwo PointersString9 companies
- Next Greater Element IeasyArrayHash TableStackMonotonic Stack9 companies
- Construct Binary Tree from Preorder and Inorder TraversalmediumArrayHash TableDivide and ConquerTree+19 companies
- Edit DistancemediumStringDynamic Programming9 companies
- Counting BitseasyDynamic ProgrammingBit Manipulation9 companies
- Pacific Atlantic Water FlowmediumArrayDepth-First SearchBreadth-First SearchMatrix9 companies
- Next Greater Element IImediumArrayStackMonotonic Stack9 companies
- Meeting RoomseasyArraySortingQuicksort9 companies
- 01 MatrixmediumArrayDynamic ProgrammingBreadth-First SearchMatrix9 companies
- Reverse Linked List IImediumLinked List9 companies
- Permutations IImediumArrayBacktrackingSorting9 companies
- Surrounded RegionsmediumArrayDepth-First SearchBreadth-First SearchUnion-Find+19 companies
- Snakes and LaddersmediumArrayBreadth-First SearchMatrix9 companies
- Is Graph Bipartite?mediumDepth-First SearchBreadth-First SearchUnion-FindGraph Theory+29 companies
- Candy CrushmediumArrayTwo PointersMatrixSimulation8 companies
- Compare Version NumbersmediumTwo PointersString8 companies
- Count Palindromic SubsequenceshardStringDynamic Programming8 companies
- Frequency of the Most Frequent ElementmediumArrayBinary SearchGreedySliding Window+28 companies
- Minimum Remove to Make Valid ParenthesesmediumStringStack8 companies
- Intersection of Two ArrayseasyArrayHash TableTwo PointersBinary Search+18 companies
- Design SkiplisthardLinked ListDesign8 companies
- Longest Mountain in ArraymediumArrayTwo PointersDynamic ProgrammingEnumeration8 companies
- Minimize Malware SpreadhardArrayHash TableDepth-First SearchBreadth-First Search+28 companies
- Longest Continuous Subarray With Absolute Diff Less Than or Equal to LimitmediumArrayQueueSliding WindowHeap (Priority Queue)+28 companies
- Lowest Common Ancestor of a Binary Search TreemediumTreeDepth-First SearchBinary Search TreeBinary Tree+28 companies
- Pascal's TriangleeasyArrayDynamic Programming8 companies
- Kth Largest Element in a StreameasyTreeDesignBinary Search TreeHeap (Priority Queue)+28 companies
- Design a Text EditorhardLinked ListStringStackDesign+28 companies
- Word PatterneasyHash TableString8 companies
- Meeting SchedulermediumArrayTwo PointersSorting8 companies
- Encode and Decode StringsmediumArrayStringDesign8 companies
- Remove Duplicate LettersmediumStringStackGreedyMonotonic Stack8 companies
- Rotate ArraymediumArrayMathTwo Pointers8 companies
- Remove Sub-Folders from the FilesystemmediumArrayStringDepth-First SearchTrie8 companies
- Guess the WordhardArrayMathStringMinimax+28 companies
- Shortest Word DistanceeasyArrayString8 companies
- Combination Sum IVmediumArrayDynamic Programming8 companies
- Backspace String CompareeasyTwo PointersStringStackSimulation8 companies
- Design Excel Sum FormulahardArrayHash TableStringGraph Theory+38 companies
- Car FleetmediumArrayStackSortingMonotonic Stack8 companies
- Path Sum IIImediumTreeDepth-First SearchBinary Tree8 companies
- Remove Invalid ParentheseshardStringBacktrackingBreadth-First Search8 companies
- Remove Duplicates from Sorted ArrayeasyArrayTwo Pointers8 companies
- Last Stone WeighteasyArrayHeap (Priority Queue)8 companies
- Network Delay TimemediumDepth-First SearchBreadth-First SearchGraph TheoryHeap (Priority Queue)+28 companies
- Flood FilleasyArrayDepth-First SearchBreadth-First SearchMatrix8 companies
- Reverse Vowels of a StringeasyTwo PointersString8 companies
- Implement Queue using StackseasyStackDesignQueue8 companies
Listings only — titles, difficulty, and tags link out to LeetCode. Imported from the leetcode-company-wise-problems snapshot dated 1 June 2025. Frequency is that dataset's own relative score within a company and time range.