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
- Read N Characters Given Read4easyArraySimulationInteractivefrequency 23.4
- Remove Duplicate LettersmediumStringStackGreedyMonotonic Stackfrequency 23.4
- Repeated DNA SequencesmediumHash TableStringBit ManipulationSliding Window+4frequency 23.4
- Reported Posts IImediumDatabasefrequency 23.4
- Reverse BitseasyDivide and ConquerBit Manipulationfrequency 23.4
- Separate the Digits in an ArrayeasyArraySimulationfrequency 23.4
- Set MismatcheasyArrayHash TableBit ManipulationSortingfrequency 23.4
- Subarray Sums Divisible by KmediumArrayHash TablePrefix Sumfrequency 23.4
- Substring with Concatenation of All WordshardHash TableStringSliding Windowfrequency 23.4
- Sum of Two IntegersmediumMathBit Manipulationfrequency 23.4
- Threshold Majority QuerieshardArrayHash TableBinary SearchDivide and Conquer+2frequency 23.4
- 132 PatternmediumArrayBinary SearchStackMonotonic Stack+1frequency 21.5
- Ads PerformanceeasyDatabasefrequency 21.5
- All the Pairs With the Maximum Number of Common FollowersmediumDatabasefrequency 21.5
- Apples & OrangesmediumDatabasefrequency 21.5
- Arranging CoinseasyMathBinary Searchfrequency 21.5
- Backspace String CompareeasyTwo PointersStringStackSimulationfrequency 21.5
- Bitwise OR of Even Numbers in an ArrayeasyArrayBit ManipulationSimulationfrequency 21.5
- Boats to Save PeoplemediumArrayTwo PointersGreedySorting+1frequency 21.5
- Burst BalloonshardArrayDynamic Programmingfrequency 21.5
- Check Knight Tour ConfigurationmediumArrayDepth-First SearchBreadth-First SearchMatrix+1frequency 21.5
- Coin Change IImediumArrayDynamic ProgrammingKnapsack ProblemComplete Knapsackfrequency 21.5
- Count Binary SubstringseasyTwo PointersStringfrequency 21.5
- Count Complete Tree NodesmediumBinary SearchBit ManipulationTreeBinary Treefrequency 21.5
- Count Nodes Equal to Sum of DescendantsmediumTreeDepth-First SearchBinary Treefrequency 21.5
- Count Number of Nice SubarraysmediumArrayHash TableMathSliding Window+1frequency 21.5
- Counting BitseasyDynamic ProgrammingBit Manipulationfrequency 21.5
- Customers Who Bought All ProductsmediumDatabasefrequency 21.5
- Customers Who Bought Products A and B but Not CmediumDatabasefrequency 21.5
- Delete Duplicate EmailseasyDatabasefrequency 21.5
- Design HashMapeasyArrayHash TableLinked ListDesign+1frequency 21.5
- Design Ride Sharing SystemmediumHash TableDesignQueueData Streamfrequency 21.5
- Encode and Decode TinyURLmediumHash TableStringDesignHash Functionfrequency 21.5
- Even Odd TreemediumTreeBreadth-First SearchBinary Treefrequency 21.5
- Find Lucky Integer in an ArrayeasyArrayHash TableCountingfrequency 21.5
- Find Subsequence of Length K With the Largest SumeasyArrayHash TableSortingHeap (Priority Queue)frequency 21.5
- Find the Highest AltitudeeasyArrayPrefix Sumfrequency 21.5
- Find the K-th Character in String Game IeasyMathBit ManipulationRecursionSimulationfrequency 21.5
- Find the Smallest Balanced IndexmediumArrayPrefix Sumfrequency 21.5
- Finding the Topic of Each PosthardDatabasefrequency 21.5
- Fruits Into Baskets IIeasyArrayBinary SearchSegment TreeSimulation+1frequency 21.5
- Game Play Analysis IVmediumDatabasefrequency 21.5
- Groups of Special-Equivalent StringsmediumArrayHash TableStringSortingfrequency 21.5
- Hamming DistanceeasyBit Manipulationfrequency 21.5
- Implement Queue using StackseasyStackDesignQueuefrequency 21.5
- Inorder Successor in BSTmediumTreeDepth-First SearchBinary Search TreeBinary Treefrequency 21.5
- Insert Delete GetRandom O(1) - Duplicates allowedhardArrayHash TableMathDesign+1frequency 21.5
- Jewels and StoneseasyHash TableStringfrequency 21.5
- Longest Subsequence Repeated k TimeshardHash TableTwo PointersStringBacktracking+2frequency 21.5
- Make Two Arrays Equal by Reversing SubarrayseasyArrayHash TableSortingfrequency 21.5
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.