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
- NPV QuerieseasyDatabase1 company
- Optimal DivisionmediumArrayMathDynamic Programming1 company
- Prison Cells After N DaysmediumArrayHash TableMathBit Manipulation+11 company
- Replace Elements in an ArraymediumArrayHash TableSimulation1 company
- Replace Question Marks in String to Minimize Its ValuemediumHash TableStringGreedySorting+21 company
- Sales by Day of the WeekhardDatabase1 company
- Sum of Beauty in the ArraymediumArray1 company
- Total Sum of Interaction Cost in Tree GroupshardArrayTreeDepth-First Search1 company
- Ads PerformanceeasyDatabase1 company
- All the Pairs With the Maximum Number of Common FollowersmediumDatabase1 company
- Apples & OrangesmediumDatabase1 company
- Count Nodes Equal to Sum of DescendantsmediumTreeDepth-First SearchBinary Tree1 company
- Customers Who Bought Products A and B but Not CmediumDatabase1 company
- Finding the Topic of Each PosthardDatabase1 company
- Groups of Special-Equivalent StringsmediumArrayHash TableStringSorting1 company
- Maximum Number of Darts Inside of a Circular DartboardhardArrayMathGeometry1 company
- Moving Stones Until ConsecutivemediumMathBrainteaser1 company
- Moving Stones Until Consecutive IImediumArrayMathSliding WindowSorting1 company
- Number Of Corner RectanglesmediumArrayMathDynamic ProgrammingMatrix1 company
- Number of Comments per PosteasyDatabase1 company
- Project Employees IIeasyDatabase1 company
- Project Employees IIImediumDatabase1 company
- Reported PostseasyDatabase1 company
- Steps to Make Array Non-decreasingmediumArrayLinked ListDynamic ProgrammingStack+21 company
- User Activity for the Past 30 Days IIeasyDatabase1 company
- Design a Todo ListmediumArrayHash TableStringDesign+11 company
- Build a Matrix With ConditionshardArrayGraph TheoryTopological SortMatrix+11 company
- Cat and Mouse IIhardArrayMathDynamic ProgrammingGraph Theory+61 company
- Closest Nodes Queries in a Binary Search TreemediumArrayBinary SearchTreeDepth-First Search+21 company
- Disconnect Path in a Binary Matrix by at Most One FlipmediumArrayDynamic ProgrammingDepth-First SearchBreadth-First Search+11 company
- Evaluate Boolean Binary TreeeasyTreeDepth-First SearchBinary Tree1 company
- Freedom TrailhardStringDynamic ProgrammingDepth-First SearchBreadth-First Search1 company
- Image OverlapmediumArrayMatrix1 company
- Latest Time by Replacing Hidden DigitseasyStringGreedy1 company
- License Key FormattingeasyString1 company
- Maximize Subarray GCD ScorehardArrayMathEnumerationNumber Theory1 company
- Maximum Area Rectangle With Point Constraints ImediumArrayMathBinary Indexed TreeSegment Tree+31 company
- Next Closest TimemediumHash TableStringBacktrackingEnumeration1 company
- Number of Restricted Paths From First to Last NodemediumDynamic ProgrammingGraph TheoryTopological SortHeap (Priority Queue)+21 company
- Number of Stable SubsequenceshardArrayDynamic Programming1 company
- Partition StringmediumHash TableStringTrieSimulation1 company
- Redundant Connection IIhardDepth-First SearchBreadth-First SearchUnion-FindGraph Theory1 company
- Sentence Screen FittingmediumArrayStringDynamic Programming1 company
- Smallest Rectangle Enclosing Black PixelshardArrayBinary SearchDepth-First SearchBreadth-First Search+11 company
- The Number of Weak Characters in the GamemediumArrayStackGreedySorting+11 company
- Verify Preorder Serialization of a Binary TreemediumStringStackTreeBinary Tree1 company
- Watering PlantsmediumArraySimulation1 company
- Count of IntegershardMathStringDynamic Programming1 company
- Find Shortest Path with K HopshardGraph TheoryHeap (Priority Queue)Shortest Path1 company
- Minimum Cost to Reach City With DiscountsmediumGraph TheoryHeap (Priority Queue)Shortest PathDijkstra's Algorithm1 company
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.