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
- Shortest Path to Get All KeyshardArrayBit ManipulationBreadth-First SearchMatrix6 companies
- String Compression IIImediumString6 companies
- Count Unguarded Cells in the GridmediumArrayMatrixSimulation6 companies
- Maximum 69 NumbereasyMathGreedy6 companies
- Number of Steps to Reduce a Number to ZeroeasyMathBit Manipulation6 companies
- Invalid TweetseasyDatabase6 companies
- Web CrawlermediumStringDepth-First SearchBreadth-First SearchInteractive6 companies
- Stock Price FluctuationmediumHash TableDesignHeap (Priority Queue)Data Stream+16 companies
- Binary GapeasyBit Manipulation6 companies
- Investments in 2016mediumDatabase6 companies
- Number of Black BlocksmediumArrayHash TableEnumeration6 companies
- One Edit DistancemediumTwo PointersString6 companies
- Time Needed to Buy TicketseasyArrayQueueSimulation6 companies
- Trapping Rain Water IIhardArrayBreadth-First SearchHeap (Priority Queue)Matrix6 companies
- Find Duplicate File in SystemmediumArrayHash TableString6 companies
- House Robber IVmediumArrayBinary SearchDynamic ProgrammingGreedy6 companies
- Knight DialermediumDynamic Programming6 companies
- Power of FoureasyMathBit ManipulationRecursion6 companies
- Number of Islands IIhardArrayHash TableUnion-Find6 companies
- Brace ExpansionmediumStringBacktrackingStackBreadth-First Search+16 companies
- Vowel SpellcheckermediumArrayHash TableString6 companies
- Minimum Cost Path with Edge ReversalsmediumGraph TheoryHeap (Priority Queue)Shortest Path6 companies
- Minimum Absolute Difference Between Elements With ConstraintmediumArrayBinary SearchOrdered Set6 companies
- Collect Coins in a TreehardArrayTreeGraph TheoryTopological Sort6 companies
- Step-By-Step Directions From a Binary Tree Node to AnothermediumStringTreeDepth-First SearchBinary Tree+26 companies
- Detonate the Maximum BombsmediumArrayMathDepth-First SearchBreadth-First Search+26 companies
- Maximum Total Damage With Spell CastingmediumArrayHash TableTwo PointersBinary Search+36 companies
- Smallest Subsequence of Distinct CharactersmediumStringStackGreedyMonotonic Stack6 companies
- Find the Closest PalindromehardMathString6 companies
- Maximum Length of Repeated SubarraymediumArrayBinary SearchDynamic ProgrammingSliding Window+26 companies
- Closest Binary Search Tree ValueeasyBinary SearchTreeDepth-First SearchBinary Search Tree+16 companies
- Palindrome PairshardArrayHash TableStringTrie+16 companies
- Count Subarrays Where Max Element Appears at Least K TimesmediumArraySliding Window6 companies
- Nim GameeasyMathBrainteaserMinimaxGame Theory+26 companies
- Transpose MatrixeasyArrayMatrixSimulation6 companies
- Search Insert PositioneasyArrayBinary Search6 companies
- Single-Threaded CPUmediumArraySortingHeap (Priority Queue)6 companies
- Perfect NumbereasyMath6 companies
- Sum of Left LeaveseasyTreeDepth-First SearchBreadth-First SearchBinary Tree6 companies
- Count Ways To Build Good StringsmediumDynamic Programming6 companies
- Matchsticks to SquaremediumArrayDynamic ProgrammingBacktrackingBit Manipulation+16 companies
- Sort Array By ParityeasyArrayTwo PointersSorting6 companies
- Sort Array by Increasing FrequencyeasyArrayHash TableSorting6 companies
- Max Number of K-Sum PairsmediumArrayHash TableTwo PointersSorting6 companies
- Number of Substrings Containing All Three CharactersmediumHash TableStringSliding Window6 companies
- Recover a Tree From Preorder TraversalhardStringTreeDepth-First SearchBinary Tree6 companies
- Merge Strings AlternatelyeasyTwo PointersString6 companies
- Count and SaymediumString6 companies
- Kth Missing Positive NumbereasyArrayBinary Search6 companies
- Valid NumberhardString6 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.