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
2,011 questions at Amazon · all time
- Count of Smaller Numbers After SelfhardArrayBinary SearchDivide and ConquerBinary Indexed Tree+4frequency 25.1
- Count the Hidden SequencesmediumArrayPrefix Sumfrequency 25.1
- Delete Duplicate EmailseasyDatabasefrequency 25.1
- Design Search Autocomplete SystemhardStringDepth-First SearchDesignTrie+3frequency 25.1
- Design an Array Statistics TrackerhardHash TableBinary SearchDesignQueue+3frequency 25.1
- Encode and Decode TinyURLmediumHash TableStringDesignHash Functionfrequency 25.1
- Fair Distribution of CookiesmediumArrayDynamic ProgrammingBacktrackingBit Manipulation+1frequency 25.1
- Find and Replace PatternmediumArrayHash TableStringfrequency 25.1
- Find the Maximum Number of Elements in SubsetmediumArrayHash TableEnumerationfrequency 25.1
- Get Watched Videos by Your FriendsmediumArrayHash TableBreadth-First SearchGraph Theory+1frequency 25.1
- Intersection of Two Arrays IIeasyArrayHash TableTwo PointersBinary Search+1frequency 25.1
- K-diff Pairs in an ArraymediumArrayHash TableTwo PointersBinary Search+1frequency 25.1
- Largest Divisible SubsetmediumArrayMathDynamic ProgrammingSortingfrequency 25.1
- Lexicographically Maximum MEX ArrayhardArrayHash TableGreedyQueuefrequency 25.1
- Longest Increasing Path in a MatrixhardArrayDynamic ProgrammingDepth-First SearchBreadth-First Search+5frequency 25.1
- Longest PalindromeeasyHash TableStringGreedyfrequency 25.1
- Max StackhardLinked ListStackDesignDoubly-Linked List+1frequency 25.1
- Maximize Happiness of Selected ChildrenmediumArrayGreedySortingfrequency 25.1
- Maximize Y‑Sum by Picking a Triplet of Distinct X‑ValuesmediumArrayHash TableGreedySorting+1frequency 25.1
- Maximum Bitwise AND After Increment OperationshardArrayGreedyBit ManipulationSortingfrequency 25.1
- Maximum Candies Allocated to K ChildrenmediumArrayBinary Searchfrequency 25.1
- Maximum Frequency StackhardHash TableStackDesignOrdered Setfrequency 25.1
- Maximum Ice Cream BarsmediumArrayGreedySortingCounting Sortfrequency 25.1
- Maximum Score Words Formed by LettershardArrayHash TableStringDynamic Programming+4frequency 25.1
- Maximum Subarray Sum with One DeletionmediumArrayDynamic Programmingfrequency 25.1
- Maximum Twin Sum of a Linked ListmediumLinked ListTwo PointersStackfrequency 25.1
- MinesweepermediumArrayDepth-First SearchBreadth-First SearchMatrixfrequency 25.1
- Minimum Genetic MutationmediumHash TableStringBreadth-First SearchBidirectional Searchfrequency 25.1
- Minimum Number of Arrows to Burst BalloonsmediumArrayGreedySortingfrequency 25.1
- Minimum Number of Moves to Make PalindromehardTwo PointersStringGreedyBinary Indexed Treefrequency 25.1
- Minimum Number of Operations to Sort a Binary Tree by LevelmediumTreeBreadth-First SearchBinary Treefrequency 25.1
- Minimum Operations to Sort a PermutationmediumArrayfrequency 25.1
- Minimum Operations to Sort a StringmediumStringfrequency 25.1
- Minimum Sum of Four Digit Number After Splitting DigitseasyMathGreedySortingfrequency 25.1
- Minimum Sum of Squared DifferencemediumArrayBinary SearchGreedySorting+1frequency 25.1
- Moving Average from Data StreameasyArrayDesignQueueData Streamfrequency 25.1
- Nested List Weight SummediumDepth-First SearchBreadth-First Searchfrequency 25.1
- Number of Dice Rolls With Target SummediumDynamic Programmingfrequency 25.1
- Number of Distinct Islands IIhardArrayHash TableDepth-First SearchBreadth-First Search+4frequency 25.1
- Number of Smooth Descent Periods of a StockmediumArrayMathTwo PointersDynamic Programming+1frequency 25.1
- Number of Substrings Containing All Three CharactersmediumHash TableStringSliding Windowfrequency 25.1
- Optimal Partition of StringmediumHash TableStringGreedyfrequency 25.1
- Orderly QueuehardMathStringSortingLexicographically Minimal String Rotationfrequency 25.1
- Path With Minimum EffortmediumArrayBinary SearchDepth-First SearchBreadth-First Search+4frequency 25.1
- Power of ThreeeasyMathRecursionfrequency 25.1
- Queries Quality and PercentageeasyDatabasefrequency 25.1
- Reformat Department TableeasyDatabasefrequency 25.1
- Remove All Occurrences of a SubstringmediumStringStackSimulationfrequency 25.1
- Serialize and Deserialize BSTmediumStringTreeDepth-First SearchBreadth-First Search+3frequency 25.1
- Serialize and Deserialize N-ary TreehardStringTreeDepth-First SearchBreadth-First Searchfrequency 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.