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
2,344 questions at Google · all time
- Reconstruct Original Digits from EnglishmediumHash TableMathStringfrequency 10.5
- Reformat Department TableeasyDatabasefrequency 10.5
- Regions Cut By SlashesmediumArrayHash TableDepth-First SearchBreadth-First Search+3frequency 10.5
- Remove Letter To Equalize FrequencyeasyHash TableStringCountingfrequency 10.5
- Removing Stars From a StringmediumStringStackSimulationfrequency 10.5
- Replace Non-Coprime Numbers in ArrayhardArrayMathStackNumber Theory+2frequency 10.5
- Restaurant GrowthmediumDatabasefrequency 10.5
- Score of ParenthesesmediumStringStackBracket Sequencesfrequency 10.5
- Smallest Palindromic Rearrangement IIhardHash TableMathStringCombinatorics+1frequency 10.5
- Sort Byeasyfrequency 10.5
- Sort Matrix by DiagonalsmediumArraySortingMatrixfrequency 10.5
- Spiral Matrix IIImediumArrayMatrixSimulationfrequency 10.5
- Strong Password CheckerhardStringGreedyHeap (Priority Queue)frequency 10.5
- Successful Pairs of Spells and PotionsmediumArrayTwo PointersBinary SearchSortingfrequency 10.5
- Sum of DistancesmediumArrayHash TablePrefix Sumfrequency 10.5
- Taking Maximum Energy From the Mystic DungeonmediumArrayDynamic ProgrammingPrefix Sumfrequency 10.5
- Tallest BillboardhardArrayDynamic ProgrammingMeet in the MiddleKnapsack Problem+1frequency 10.5
- Tenth LineeasyShellfrequency 10.5
- The Number of the Smallest Unoccupied ChairmediumArrayHash TableHeap (Priority Queue)frequency 10.5
- Three DivisorseasyMathEnumerationNumber TheoryPrime Factorization+1frequency 10.5
- Transpose FilemediumShellfrequency 10.5
- Uncommon Words from Two SentenceseasyHash TableStringCountingfrequency 10.5
- Univalued Binary TreeeasyTreeDepth-First SearchBreadth-First SearchBinary Treefrequency 10.5
- Valid WordeasyStringfrequency 10.5
- Verifying an Alien DictionaryeasyArrayHash TableStringfrequency 10.5
- Word FrequencymediumShellfrequency 10.5
- 3Sum With MultiplicitymediumArrayHash TableTwo PointersSorting+1frequency 8.1
- Actors and Directors Who Cooperated At Least Three TimeseasyDatabasefrequency 8.1
- All Paths From Source to TargetmediumBacktrackingDepth-First SearchBreadth-First SearchGraph Theory+1frequency 8.1
- Amount of Time for Binary Tree to Be InfectedmediumHash TableTreeDepth-First SearchBreadth-First Search+1frequency 8.1
- Analyze User Website Visit PatternmediumArrayHash TableStringSortingfrequency 8.1
- Apple Redistribution into BoxeseasyArrayGreedySortingfrequency 8.1
- Basic Calculator IVhardHash TableMathStringStack+1frequency 8.1
- Best Meeting PointhardArrayMathSortingMatrixfrequency 8.1
- Check If Digits Are Equal in String After Operations IeasyMathStringSimulationCombinatorics+1frequency 8.1
- Check If It Is a Good ArrayhardArrayMathNumber TheoryBézout's Lemma+3frequency 8.1
- Check if Matrix Is X-MatrixeasyArrayMatrixfrequency 8.1
- Check if Object Instance of Classmediumfrequency 8.1
- Check if One String Swap Can Make Strings EqualeasyHash TableStringCountingfrequency 8.1
- Circular Array LoopmediumArrayHash TableTwo PointersFloyd's Cycle Finding Algorithmfrequency 8.1
- Closest Subsequence SumhardArrayTwo PointersDynamic ProgrammingBit Manipulation+3frequency 8.1
- Concatenation of Consecutive Binary NumbersmediumMathBit ManipulationSimulationfrequency 8.1
- Constrained Subsequence SumhardArrayDynamic ProgrammingQueueSliding Window+2frequency 8.1
- Convert BST to Greater TreemediumTreeDepth-First SearchBinary Search TreeBinary Treefrequency 8.1
- Count Number of Pairs With Absolute Difference KeasyArrayHash TableCountingfrequency 8.1
- Count Partitions with Even Sum DifferenceeasyArrayMathPrefix Sumfrequency 8.1
- Count Sub IslandsmediumArrayDepth-First SearchBreadth-First SearchUnion-Find+1frequency 8.1
- Count Submatrices with Top-Left Element and Sum Less Than kmediumArrayMatrixPrefix Sumfrequency 8.1
- Count Total Number of Colored CellsmediumMathfrequency 8.1
- Count Univalue SubtreesmediumTreeDepth-First SearchBinary TreeDP on Treesfrequency 8.1
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.