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
- Construct Quad TreemediumArrayDivide and ConquerTreeMatrix7 companies
- Maximize Distance to Closest PersonmediumArray7 companies
- Count Vowel Substrings of a StringeasyHash TableString7 companies
- Parallel CoursesmediumGraph TheoryTopological SortDirected Acyclic Graph7 companies
- Repeated DNA SequencesmediumHash TableStringBit ManipulationSliding Window+47 companies
- Frog JumphardArrayDynamic Programming7 companies
- Unique Binary Search TreesmediumMathDynamic ProgrammingTreeBinary Search Tree+17 companies
- 24 GamehardArrayMathBacktracking7 companies
- Minimum Number of Refueling StopshardArrayDynamic ProgrammingGreedyHeap (Priority Queue)7 companies
- Flatten a Multilevel Doubly Linked ListmediumLinked ListDepth-First SearchDoubly-Linked List7 companies
- Add DigitseasyMathSimulationNumber Theory7 companies
- Delete Node in a Linked ListmediumLinked List7 companies
- Design SpreadsheetmediumArrayHash TableStringDesign+17 companies
- Fraction to Recurring DecimalmediumHash TableMathString7 companies
- Reverse PairshardArrayBinary SearchDivide and ConquerBinary Indexed Tree+47 companies
- Rotating the BoxmediumArrayTwo PointersMatrix7 companies
- Palindrome NumbereasyMath7 companies
- Sliding PuzzlehardArrayDynamic ProgrammingBacktrackingBreadth-First Search+57 companies
- Redundant ConnectionmediumDepth-First SearchBreadth-First SearchUnion-FindGraph Theory7 companies
- Merge In Between Linked ListsmediumLinked List7 companies
- Maximum SwapmediumMathGreedy7 companies
- Minimum Swaps to Group All 1's Together IImediumArraySliding Window7 companies
- Number of Ways to Form a Target String Given a DictionaryhardArrayStringDynamic Programming7 companies
- Partition to K Equal Sum SubsetsmediumArrayDynamic ProgrammingBacktrackingBit Manipulation+27 companies
- Count Number of Nice SubarraysmediumArrayHash TableMathSliding Window+17 companies
- Greatest Sum Divisible by ThreemediumArrayDynamic ProgrammingGreedySorting7 companies
- Path With Minimum EffortmediumArrayBinary SearchDepth-First SearchBreadth-First Search+47 companies
- Maximum Number of Occurrences of a SubstringmediumHash TableStringSliding Window7 companies
- Next Greater Element IIImediumMathTwo PointersString7 companies
- Best Time to Buy and Sell Stock with CooldownmediumArrayDynamic Programming7 companies
- Target SummediumArrayDynamic ProgrammingBacktrackingKnapsack Problem+17 companies
- Excel Sheet Column NumbereasyMathString7 companies
- Interleaving StringmediumStringDynamic Programming7 companies
- Shortest Unsorted Continuous SubarraymediumArrayTwo PointersStackGreedy+27 companies
- First Bad VersioneasyBinary SearchInteractive7 companies
- Merge Two Binary TreeseasyTreeDepth-First SearchBreadth-First SearchBinary Tree7 companies
- Robot Room CleanerhardBacktrackingInteractive7 companies
- Sort Characters By FrequencymediumHash TableStringSortingHeap (Priority Queue)+27 companies
- Binary Search Tree IteratormediumStackTreeDesignBinary Search Tree+27 companies
- Find the Winner of the Circular GamemediumArrayMathRecursionQueue+17 companies
- Add Two IntegerseasyMath7 companies
- Palindrome PartitioningmediumStringDynamic ProgrammingBacktracking7 companies
- Binary SearcheasyArrayBinary Search7 companies
- Delete and EarnmediumArrayHash TableDynamic Programming7 companies
- Find the Index of the First Occurrence in a StringeasyTwo PointersStringString MatchingZ Algorithm+27 companies
- Rotate ListmediumLinked ListTwo Pointers7 companies
- Peak Index in a Mountain ArraymediumArrayBinary SearchTernary Search7 companies
- Furthest Building You Can ReachmediumArrayGreedyHeap (Priority Queue)7 companies
- Subarray Sums Divisible by KmediumArrayHash TablePrefix Sum7 companies
- Zigzag ConversionmediumString7 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.