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
- Project Employees IeasyDatabasefrequency 26.7
- Queries Quality and PercentageeasyDatabasefrequency 26.7
- Rank ScoresmediumDatabasefrequency 26.7
- Remove Linked List ElementseasyLinked ListRecursionfrequency 26.7
- Remove Outermost ParentheseseasyStringStackBracket Sequencesfrequency 26.7
- Reorganize StringmediumHash TableStringGreedySorting+2frequency 26.7
- Reverse Vowels of a StringeasyTwo PointersStringfrequency 26.7
- Sum of Unique ElementseasyArrayHash TableCountingfrequency 26.7
- Unique Number of OccurrenceseasyArrayHash Tablefrequency 26.7
- Word Search IIhardArrayStringBacktrackingTrie+1frequency 26.7
- Assign CookieseasyArrayTwo PointersGreedySorting+1frequency 25.1
- Average of Levels in Binary TreeeasyTreeDepth-First SearchBreadth-First SearchBinary Treefrequency 25.1
- Binary Search Tree Iterator IImediumStackTreeDesignBinary Search Tree+2frequency 25.1
- Build Array from PermutationeasyArraySimulationfrequency 25.1
- Calculate Amount Paid in TaxeseasyArraySimulationfrequency 25.1
- Cheapest Flights Within K StopsmediumDynamic ProgrammingDepth-First SearchBreadth-First SearchGraph Theory+2frequency 25.1
- Count Pairs Whose Sum is Less than TargeteasyArrayTwo PointersBinary SearchSortingfrequency 25.1
- Decode Ways IIhardStringDynamic Programmingfrequency 25.1
- Design Add and Search Words Data StructuremediumStringDepth-First SearchDesignTriefrequency 25.1
- Design Circular QueuemediumArrayLinked ListDesignQueuefrequency 25.1
- Design Search Autocomplete SystemhardStringDepth-First SearchDesignTrie+3frequency 25.1
- Find Kth Bit in Nth Binary StringmediumStringRecursionSimulationfrequency 25.1
- Find Missing and Repeated ValueseasyArrayHash TableMathMatrixfrequency 25.1
- Find Numbers with Even Number of DigitseasyArrayMathfrequency 25.1
- Find Winner on a Tic Tac Toe GameeasyArrayHash TableMatrixSimulationfrequency 25.1
- First Unique Character in a StringeasyHash TableStringQueueCountingfrequency 25.1
- Flood FilleasyArrayDepth-First SearchBreadth-First SearchMatrixfrequency 25.1
- Fraction to Recurring DecimalmediumHash TableMathStringfrequency 25.1
- Friend Requests I: Overall Acceptance RateeasyDatabasefrequency 25.1
- H-IndexmediumArraySortingCounting Sortfrequency 25.1
- H-Index IImediumArrayBinary Searchfrequency 25.1
- Immediate Food Delivery IImediumDatabasefrequency 25.1
- Intersection of Two Arrays IIeasyArrayHash TableTwo PointersBinary Search+1frequency 25.1
- Largest BST SubtreemediumDynamic ProgrammingTreeDepth-First SearchBinary Search Tree+2frequency 25.1
- Largest Odd Number in StringeasyMathStringGreedyfrequency 25.1
- Largest Plus SignmediumArrayDynamic Programmingfrequency 25.1
- Lemonade ChangeeasyArrayGreedyfrequency 25.1
- Max Number of K-Sum PairsmediumArrayHash TableTwo PointersSortingfrequency 25.1
- Maximum Sum Circular SubarraymediumArrayDivide and ConquerDynamic ProgrammingQueue+1frequency 25.1
- Minimum Cost to Reach Destination in TimehardArrayDynamic ProgrammingGraph TheoryDijkstra's Algorithmfrequency 25.1
- Minimum Deletions for At Most K Distinct CharacterseasyHash TableStringGreedySorting+1frequency 25.1
- Minimum Number of Days to Make m BouquetsmediumArrayBinary Searchfrequency 25.1
- N-Queens IIhardBacktrackingAlgorithm Xfrequency 25.1
- Number of Longest Increasing SubsequencemediumArrayDynamic ProgrammingBinary Indexed TreeSegment Tree+1frequency 25.1
- Number of Substrings Containing All Three CharactersmediumHash TableStringSliding Windowfrequency 25.1
- Page RecommendationsmediumDatabasefrequency 25.1
- Page Recommendations IIhardDatabasefrequency 25.1
- Partition Array for Maximum SummediumArrayDynamic Programmingfrequency 25.1
- Power of ThreeeasyMathRecursionfrequency 25.1
- Redundant ConnectionmediumDepth-First SearchBreadth-First SearchUnion-FindGraph Theoryfrequency 25.1
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.