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
298 questions at Apple · all time
- Two Sum II - Input Array Is SortedmediumArrayTwo PointersBinary Searchfrequency 46.0
- Coin ChangemediumArrayDynamic ProgrammingBreadth-First SearchKnapsack Problem+1frequency 43.0
- Design Memory AllocatormediumArrayHash TableDesignSimulationfrequency 43.0
- Find All Lonely Numbers in the ArraymediumArrayHash TableCountingfrequency 43.0
- Insert IntervalmediumArrayfrequency 43.0
- Lowest Common Ancestor of a Binary Tree IIImediumHash TableTwo PointersTreeBinary Tree+2frequency 43.0
- PermutationsmediumArrayBacktrackingfrequency 43.0
- Reverse StringeasyTwo PointersStringfrequency 43.0
- Sliding Window MaximumhardArrayQueueSliding WindowHeap (Priority Queue)+2frequency 43.0
- String to Integer (atoi)mediumStringfrequency 43.0
- Text JustificationhardArrayStringSimulationfrequency 43.0
- Add Two NumbersmediumLinked ListMathRecursionfrequency 39.4
- Best Time to Buy and Sell Stock with CooldownmediumArrayDynamic Programmingfrequency 39.4
- Cheapest Flights Within K StopsmediumDynamic ProgrammingDepth-First SearchBreadth-First SearchGraph Theory+2frequency 39.4
- Distribute Money to Maximum ChildreneasyMathGreedyfrequency 39.4
- Edit DistancemediumStringDynamic Programmingfrequency 39.4
- Exam RoommediumDesignHeap (Priority Queue)Ordered Setfrequency 39.4
- Find Peak ElementmediumArrayBinary Searchfrequency 39.4
- Gas StationmediumArrayGreedyfrequency 39.4
- Keys and RoomsmediumDepth-First SearchBreadth-First SearchGraph Theoryfrequency 39.4
- Maximum Frequency StackhardHash TableStackDesignOrdered Setfrequency 39.4
- Middle of the Linked ListeasyLinked ListTwo Pointersfrequency 39.4
- Path SumeasyTreeDepth-First SearchBreadth-First SearchBinary Treefrequency 39.4
- Roman to IntegereasyHash TableMathStringfrequency 39.4
- Rotting OrangesmediumArrayBreadth-First SearchMatrixfrequency 39.4
- Serialize and Deserialize N-ary TreehardStringTreeDepth-First SearchBreadth-First Searchfrequency 39.4
- Set Matrix ZeroesmediumArrayHash TableMatrixfrequency 39.4
- Total Hamming DistancemediumArrayMathBit Manipulationfrequency 39.4
- Valid AnagrameasyHash TableStringSortingfrequency 39.4
- Word SearchmediumArrayStringBacktrackingDepth-First Search+1frequency 39.4
- Alien DictionaryhardArrayStringDepth-First SearchBreadth-First Search+3frequency 35.0
- Best Time to Buy and Sell Stock IIIhardArrayDynamic Programmingfrequency 35.0
- Brace ExpansionmediumStringBacktrackingStackBreadth-First Search+1frequency 35.0
- Capacity To Ship Packages Within D DaysmediumArrayBinary Searchfrequency 35.0
- Combination SummediumArrayBacktrackingfrequency 35.0
- Convert Sorted Array to Binary Search TreeeasyArrayDivide and ConquerTreeBinary Search Tree+1frequency 35.0
- Design Add and Search Words Data StructuremediumStringDepth-First SearchDesignTriefrequency 35.0
- Design Log Storage SystemmediumHash TableStringDesignOrdered Setfrequency 35.0
- Fizz BuzzeasyMathStringSimulationfrequency 35.0
- H-IndexmediumArraySortingCounting Sortfrequency 35.0
- Happy NumbereasyHash TableMathTwo PointersFloyd's Cycle Finding Algorithmfrequency 35.0
- Interleaving StringmediumStringDynamic Programmingfrequency 35.0
- Knight Probability in ChessboardmediumDynamic Programmingfrequency 35.0
- Kth Smallest Element in a Sorted MatrixmediumArrayBinary SearchSortingHeap (Priority Queue)+1frequency 35.0
- Longest Increasing Path in a MatrixhardArrayDynamic ProgrammingDepth-First SearchBreadth-First Search+5frequency 35.0
- Maximum Path Quality of a GraphhardArrayBacktrackingGraph Theoryfrequency 35.0
- Missing NumbereasyArrayHash TableMathBinary Search+2frequency 35.0
- Odd Even Linked ListmediumLinked Listfrequency 35.0
- Palindromic SubstringsmediumTwo PointersStringDynamic Programmingfrequency 35.0
- Reconstruct ItineraryhardArrayStringDepth-First SearchGraph Theory+5frequency 35.0
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.