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
- Maximum Sum BST in Binary TreehardDynamic ProgrammingTreeDepth-First SearchBinary Search Tree+2frequency 35.1
- Minimum Add to Make Parentheses ValidmediumStringStackGreedyBracket Sequencesfrequency 35.1
- Minimum Number of Primes to Sum to TargetmediumArrayMathDynamic ProgrammingNumber Theoryfrequency 35.1
- Permutation SequencehardMathRecursionfrequency 35.1
- Remove All Adjacent Duplicates in String IImediumStringStackfrequency 35.1
- Smallest Subsequence of Distinct CharactersmediumStringStackGreedyMonotonic Stackfrequency 35.1
- Sum of Two IntegersmediumMathBit Manipulationfrequency 35.1
- Text JustificationhardArrayStringSimulationfrequency 35.1
- Count Square Submatrices with All OnesmediumArrayDynamic ProgrammingMatrixfrequency 34.2
- Is Graph Bipartite?mediumDepth-First SearchBreadth-First SearchUnion-FindGraph Theory+2frequency 34.2
- Kth Smallest Element in a Sorted MatrixmediumArrayBinary SearchSortingHeap (Priority Queue)+1frequency 34.2
- Maximum Number of Events That Can Be AttendedmediumArrayGreedySortingHeap (Priority Queue)frequency 34.2
- Minimum Falling Path SummediumArrayDynamic ProgrammingMatrixfrequency 34.2
- Number of Connected Components in an Undirected GraphmediumDepth-First SearchBreadth-First SearchUnion-FindGraph Theoryfrequency 34.2
- Permutations IImediumArrayBacktrackingSortingfrequency 34.2
- Remove All Adjacent Duplicates In StringeasyStringStackfrequency 34.2
- Remove Duplicate LettersmediumStringStackGreedyMonotonic Stackfrequency 34.2
- Repeated Substring PatterneasyStringString MatchingZ AlgorithmKnuth–Morris–Pratt Algorithmfrequency 34.2
- Replace Employee ID With The Unique IdentifiereasyDatabasefrequency 34.2
- Students and ExaminationseasyDatabasefrequency 34.2
- Swapping Nodes in a Linked ListmediumLinked ListTwo Pointersfrequency 34.2
- Two Sum IV - Input is a BSTeasyHash TableTwo PointersTreeDepth-First Search+3frequency 34.2
- Combination Sum IImediumArrayBacktrackingfrequency 33.3
- CombinationsmediumBacktrackingfrequency 33.3
- Compare Version NumbersmediumTwo PointersStringfrequency 33.3
- Consecutive NumbersmediumDatabasefrequency 33.3
- Duplicate EmailseasyDatabasefrequency 33.3
- Employee BonuseasyDatabasefrequency 33.3
- Excel Sheet Column TitleeasyMathStringfrequency 33.3
- Find All Numbers Disappeared in an ArrayeasyArrayHash Tablefrequency 33.3
- Find Longest Self-Contained SubstringhardHash TableStringSortingfrequency 33.3
- Frog JumphardArrayDynamic Programmingfrequency 33.3
- Immediate Food Delivery IImediumDatabasefrequency 33.3
- Jewels and StoneseasyHash TableStringfrequency 33.3
- Magnetic Force Between Two BallsmediumArrayBinary SearchSortingfrequency 33.3
- Most Expensive Item That Can Not Be BoughtmediumMathDynamic ProgrammingNumber Theoryfrequency 33.3
- Multiply StringsmediumMathStringSimulationfrequency 33.3
- Path Sum IIImediumTreeDepth-First SearchBinary Treefrequency 33.3
- Put Marbles in BagshardArrayGreedySortingHeap (Priority Queue)frequency 33.3
- Rank ScoresmediumDatabasefrequency 33.3
- Reconstruct ItineraryhardArrayStringDepth-First SearchGraph Theory+5frequency 33.3
- Remove Linked List ElementseasyLinked ListRecursionfrequency 33.3
- Spiral Matrix IImediumArrayMatrixSimulationfrequency 33.3
- Add StringseasyMathStringSimulationfrequency 32.3
- Best Time to Buy and Sell Stock IIIhardArrayDynamic Programmingfrequency 32.3
- Create a DataFrame from Listeasyfrequency 32.3
- Customers Who Bought All ProductsmediumDatabasefrequency 32.3
- Different Ways to Add ParenthesesmediumMathStringDynamic ProgrammingRecursion+2frequency 32.3
- Domino and Tromino TilingmediumDynamic Programmingfrequency 32.3
- Find the DifferenceeasyHash TableStringBit ManipulationSortingfrequency 32.3
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.