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
- String to Integer (atoi)mediumString16 companies
- Valid SudokumediumArrayHash TableMatrix16 companies
- Reverse Linked ListeasyLinked ListRecursion16 companies
- Letter Combinations of a Phone NumbermediumHash TableStringBacktracking16 companies
- Binary Tree Maximum Path SumhardDynamic ProgrammingTreeDepth-First SearchBinary Tree+116 companies
- Subarray Sum Equals KmediumArrayHash TablePrefix Sum16 companies
- Climbing StairseasyMathDynamic ProgrammingMemoization16 companies
- Task SchedulermediumArrayHash TableGreedySorting+216 companies
- Combination SummediumArrayBacktracking16 companies
- Container With Most WatermediumArrayTwo PointersGreedy16 companies
- Largest Rectangle in HistogramhardArrayStackMonotonic StackRange Minimum/Maximum Query16 companies
- Design Memory AllocatormediumArrayHash TableDesignSimulation15 companies
- Evaluate DivisionmediumArrayStringDepth-First SearchBreadth-First Search+515 companies
- Maximum Profit in Job SchedulinghardArrayBinary SearchDynamic ProgrammingSorting15 companies
- Alien DictionaryhardArrayStringDepth-First SearchBreadth-First Search+315 companies
- Integer to RomanmediumHash TableMathString15 companies
- Find Peak ElementmediumArrayBinary Search15 companies
- Min StackmediumStackDesign15 companies
- Accounts MergemediumArrayHash TableStringDepth-First Search+315 companies
- Best Time to Buy and Sell Stock IImediumArrayDynamic ProgrammingGreedy14 companies
- Find the Length of the Longest Common PrefixmediumArrayHash TableStringTrie14 companies
- Roman to IntegereasyHash TableMathString14 companies
- Top K Frequent WordsmediumArrayHash TableStringTrie+414 companies
- Sudoku SolverhardArrayHash TableBacktrackingMatrix+214 companies
- Clone GraphmediumHash TableDepth-First SearchBreadth-First SearchGraph Theory14 companies
- Snapshot ArraymediumArrayHash TableBinary SearchDesign+114 companies
- Word BreakmediumArrayHash TableStringDynamic Programming+314 companies
- Regular Expression MatchinghardStringDynamic ProgrammingRecursion14 companies
- Word Break IIhardArrayHash TableStringDynamic Programming+314 companies
- Making A Large IslandhardArrayDepth-First SearchBreadth-First SearchUnion-Find+114 companies
- Longest Increasing SubsequencemediumArrayBinary SearchDynamic ProgrammingLongest Increasing Subsequence14 companies
- Merge Sorted ArrayeasyArrayTwo PointersSorting14 companies
- Longest Common PrefixeasyArrayStringTrie14 companies
- Generate ParenthesesmediumStringDynamic ProgrammingBacktrackingBracket Sequences14 companies
- Move ZeroeseasyArrayTwo Pointers14 companies
- Serialize and Deserialize Binary TreehardStringTreeDepth-First SearchBreadth-First Search+214 companies
- Find K Closest ElementsmediumArrayTwo PointersBinary SearchSliding Window+214 companies
- Flatten Nested List IteratormediumStackTreeDepth-First SearchDesign+213 companies
- Integer to English WordshardMathStringRecursion13 companies
- Lowest Common Ancestor of a Binary TreemediumTreeDepth-First SearchBinary TreeBinary Lifting+113 companies
- Reconstruct ItineraryhardArrayStringDepth-First SearchGraph Theory+513 companies
- Search Suggestions SystemmediumArrayStringBinary SearchTrie+213 companies
- Shortest BridgemediumArrayDepth-First SearchBreadth-First SearchMatrix13 companies
- Simple Bank SystemmediumArrayHash TableDesignSimulation13 companies
- Simplify PathmediumStringStack13 companies
- Palindromic SubstringsmediumTwo PointersStringDynamic Programming13 companies
- Game of LifemediumArrayMatrixSimulation13 companies
- Word Search IIhardArrayStringBacktrackingTrie+113 companies
- Logger Rate LimitereasyHash TableDesignData Stream13 companies
- Pow(x, n)mediumMathRecursion13 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.