Problems
Callback's own problems and the LeetCode questions companies have been asking, in one place — filter by category, company, topic, difficulty, and how recently a question showed up.
Asked on LeetCode
348 questions at TikTok · all time
- LRU CachemediumHash TableLinked ListDesignDoubly-Linked Listfrequency 100.0
- Number of IslandsmediumArrayDepth-First SearchBreadth-First SearchUnion-Find+1frequency 97.3
- Longest Increasing SubsequencemediumArrayBinary SearchDynamic ProgrammingLongest Increasing Subsequencefrequency 89.7
- Longest Substring Without Repeating CharactersmediumHash TableStringSliding Windowfrequency 87.2
- Number of Distinct IslandsmediumArrayHash TableDepth-First SearchBreadth-First Search+4frequency 86.6
- Course Schedule IImediumDepth-First SearchBreadth-First SearchGraph TheoryTopological Sortfrequency 85.9
- Meeting Rooms IImediumArrayTwo PointersGreedySorting+2frequency 83.8
- Merge IntervalsmediumArraySortingQuicksortfrequency 83.0
- Trapping Rain WaterhardArrayTwo PointersDynamic ProgrammingStack+1frequency 83.0
- Course SchedulemediumDepth-First SearchBreadth-First SearchGraph TheoryTopological Sort+1frequency 82.3
- Text JustificationhardArrayStringSimulationfrequency 79.7
- Decode StringmediumStringStackRecursionfrequency 75.8
- Longest Palindromic SubstringmediumTwo PointersStringDynamic ProgrammingManacherfrequency 74.7
- Minimum Window SubstringhardHash TableStringSliding Windowfrequency 74.7
- Search in Rotated Sorted ArraymediumArrayBinary Searchfrequency 74.7
- Word SearchmediumArrayStringBacktrackingDepth-First Search+1frequency 74.7
- N-QueenshardArrayBacktrackingAlgorithm Xfrequency 73.6
- 3SummediumArrayTwo PointersSortingfrequency 72.4
- Coin ChangemediumArrayDynamic ProgrammingBreadth-First SearchKnapsack Problem+1frequency 71.1
- Minimum Swaps to Group All 1's TogethermediumArraySliding Windowfrequency 71.1
- Spiral MatrixmediumArrayMatrixSimulationfrequency 71.1
- Subarray Sum Equals KmediumArrayHash TablePrefix Sumfrequency 71.1
- Longest Consecutive SequencemediumArrayHash TableUnion-Findfrequency 69.8
- Subarray With Elements Greater Than Varying ThresholdhardArrayStackUnion-FindMonotonic Stackfrequency 69.8
- Top K Frequent ElementsmediumArrayHash TableDivide and ConquerSorting+4frequency 69.8
- Making A Large IslandhardArrayDepth-First SearchBreadth-First SearchUnion-Find+1frequency 68.3
- Maximum SwapmediumMathGreedyfrequency 68.3
- Merge k Sorted ListshardLinked ListDivide and ConquerHeap (Priority Queue)Merge Sort+1frequency 68.3
- Basic Calculator IIIhardMathStringStackRecursionfrequency 66.8
- House RobbermediumArrayDynamic Programmingfrequency 66.8
- Longest Happy StringmediumStringGreedyHeap (Priority Queue)frequency 66.8
- Maximum Value at a Given Index in a Bounded ArraymediumMathBinary SearchGreedyfrequency 66.8
- Snapshot ArraymediumArrayHash TableBinary SearchDesign+1frequency 66.8
- Sqrt(x)easyMathBinary SearchNewton's Methodfrequency 66.8
- Valid ParentheseseasyStringStackBracket Sequencesfrequency 66.8
- Basic Calculator IImediumMathStringStackfrequency 65.2
- Best Time to Buy and Sell StockeasyArrayDynamic Programmingfrequency 65.2
- Two SumeasyArrayHash Tablefrequency 65.2
- Insert Delete GetRandom O(1)mediumArrayHash TableMathDesign+1frequency 63.4
- Kth Largest Element in an ArraymediumArrayDivide and ConquerSortingHeap (Priority Queue)+1frequency 63.4
- Longest Increasing Path in a MatrixhardArrayDynamic ProgrammingDepth-First SearchBreadth-First Search+5frequency 63.4
- Valid Parenthesis StringmediumStringDynamic ProgrammingStackGreedy+1frequency 63.4
- Word LadderhardHash TableStringBreadth-First SearchBidirectional Searchfrequency 63.4
- Add StringseasyMathStringSimulationfrequency 61.4
- Daily TemperaturesmediumArrayStackMonotonic Stackfrequency 61.4
- Design HashMapeasyArrayHash TableLinked ListDesign+1frequency 61.4
- Find Median from Data StreamhardTwo PointersDesignSortingHeap (Priority Queue)+1frequency 61.4
- Generate ParenthesesmediumStringDynamic ProgrammingBacktrackingBracket Sequencesfrequency 61.4
- Meeting Rooms IIIhardArrayHash TableSortingHeap (Priority Queue)+1frequency 61.4
- Sort ColorsmediumArrayTwo PointersSortingQuicksort+1frequency 61.4
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.