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
1,399 questions at Meta · all time
- Exclusive Time of FunctionsmediumArrayStackfrequency 67.4
- Longest Palindromic SubstringmediumTwo PointersStringDynamic ProgrammingManacherfrequency 67.1
- Remove Duplicates from Sorted ArrayeasyArrayTwo Pointersfrequency 67.1
- Diagonal TraversemediumArrayMatrixSimulationfrequency 67.0
- Median of Two Sorted ArrayshardArrayBinary SearchDivide and Conquerfrequency 66.8
- All Nodes Distance K in Binary TreemediumHash TableTreeDepth-First SearchBreadth-First Search+1frequency 65.7
- Course SchedulemediumDepth-First SearchBreadth-First SearchGraph TheoryTopological Sort+1frequency 65.7
- Number of IslandsmediumArrayDepth-First SearchBreadth-First SearchUnion-Find+1frequency 65.5
- Move ZeroeseasyArrayTwo Pointersfrequency 65.3
- Remove Nth Node From End of ListmediumLinked ListTwo Pointersfrequency 64.7
- Palindrome NumbereasyMathfrequency 64.1
- Convert Binary Search Tree to Sorted Doubly Linked ListmediumLinked ListStackTreeDepth-First Search+3frequency 63.7
- Add StringseasyMathStringSimulationfrequency 63.6
- Insert into a Sorted Circular Linked ListmediumLinked Listfrequency 63.4
- Palindromic SubstringsmediumTwo PointersStringDynamic Programmingfrequency 63.0
- Trapping Rain WaterhardArrayTwo PointersDynamic ProgrammingStack+1frequency 62.6
- Robot Room CleanerhardBacktrackingInteractivefrequency 62.4
- Container With Most WatermediumArrayTwo PointersGreedyfrequency 62.2
- Closest Binary Search Tree ValueeasyBinary SearchTreeDepth-First SearchBinary Search Tree+1frequency 61.8
- SubsetsmediumArrayBacktrackingBit Manipulationfrequency 61.8
- Accounts MergemediumArrayHash TableStringDepth-First Search+3frequency 61.4
- Group Shifted StringsmediumArrayHash TableStringfrequency 61.4
- Goat LatineasyStringfrequency 61.1
- Roman to IntegereasyHash TableMathStringfrequency 61.1
- Binary Search Tree IteratormediumStackTreeDesignBinary Search Tree+2frequency 60.9
- Maximum SubarraymediumArrayDivide and ConquerDynamic Programmingfrequency 60.5
- Continuous Subarray SummediumArrayHash TableMathPrefix Sum+1frequency 59.8
- Random Pick IndexmediumHash TableMathReservoir SamplingRandomizedfrequency 59.1
- Expression Add OperatorshardMathStringBacktrackingfrequency 58.8
- Generate ParenthesesmediumStringDynamic ProgrammingBacktrackingBracket Sequencesfrequency 58.6
- Group AnagramsmediumArrayHash TableStringSortingfrequency 58.6
- Koko Eating BananasmediumArrayBinary Searchfrequency 58.6
- Contains Duplicate IIeasyArrayHash TableSliding Windowfrequency 58.4
- Merge Two Sorted ListseasyLinked ListRecursionfrequency 58.1
- Search in Rotated Sorted ArraymediumArrayBinary Searchfrequency 58.1
- Letter Combinations of a Phone NumbermediumHash TableStringBacktrackingfrequency 57.8
- Majority ElementeasyArrayHash TableDivide and ConquerSorting+2frequency 57.8
- Merge Strings AlternatelyeasyTwo PointersStringfrequency 57.8
- Valid Palindrome IIIhardStringDynamic Programmingfrequency 57.8
- Sliding Window MedianhardArrayHash TableSliding WindowHeap (Priority Queue)+1frequency 57.6
- Word LadderhardHash TableStringBreadth-First SearchBidirectional Searchfrequency 57.6
- String to Integer (atoi)mediumStringfrequency 57.3
- Climbing StairseasyMathDynamic ProgrammingMemoizationfrequency 56.8
- Longest Consecutive SequencemediumArrayHash TableUnion-Findfrequency 56.8
- Recyclable and Low Fat ProductseasyDatabasefrequency 56.8
- Sort ColorsmediumArrayTwo PointersSortingQuicksort+1frequency 56.8
- Kth Smallest Element in a Sorted MatrixmediumArrayBinary SearchSortingHeap (Priority Queue)+1frequency 55.9
- Set Matrix ZeroesmediumArrayHash TableMatrixfrequency 55.9
- Remove All Adjacent Duplicates In StringeasyStringStackfrequency 55.6
- Reverse IntegermediumMathfrequency 55.3
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.