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
- Find the K-Sum of an ArrayhardArraySortingHeap (Priority Queue)frequency 26.5
- GCD Sort of an ArrayhardArrayMathUnion-FindSorting+4frequency 26.5
- Insert into a Binary Search TreemediumTreeBinary Search TreeBinary Treefrequency 26.5
- Invalid TweetseasyDatabasefrequency 26.5
- Largest Odd Number in StringeasyMathStringGreedyfrequency 26.5
- Lexicographical NumbersmediumDepth-First SearchTriefrequency 26.5
- List the Products Ordered in a PeriodeasyDatabasefrequency 26.5
- Logger Rate LimitereasyHash TableDesignData Streamfrequency 26.5
- Longest Duplicate SubstringhardStringBinary SearchSliding WindowRolling Hash+6frequency 26.5
- Loud and RichmediumArrayDepth-First SearchGraph TheoryTopological Sort+1frequency 26.5
- Lowest Common Ancestor of a Binary Tree IVmediumHash TableTreeDepth-First SearchBinary Tree+2frequency 26.5
- Max Number of K-Sum PairsmediumArrayHash TableTwo PointersSortingfrequency 26.5
- Maximize Fixed Points After DeletionshardArrayBinary SearchSortingfrequency 26.5
- Maximum Difference Between Node and AncestormediumTreeDepth-First SearchBinary Treefrequency 26.5
- Maximum Element After Decreasing and RearrangingmediumArrayGreedySortingfrequency 26.5
- Maximum Nesting Depth of the ParentheseseasyStringStackBracket Sequencesfrequency 26.5
- Maximum Number of Robots Within BudgethardArrayBinary SearchQueueSliding Window+3frequency 26.5
- Maximum Total from Optimal Activation OrdermediumArrayTwo PointersGreedySorting+1frequency 26.5
- Minimum Array SummediumArrayDynamic Programmingfrequency 26.5
- Minimum Number of Operations to Make Elements in Array DistincteasyArrayHash Tablefrequency 26.5
- Minimum Number of Pushes to Type Word IeasyMathStringGreedyfrequency 26.5
- Minimum Number of Pushes to Type Word IImediumHash TableStringGreedySorting+1frequency 26.5
- Minimum Removals to Balance ArraymediumArrayBinary SearchSliding WindowSortingfrequency 26.5
- Minimum Rounds to Complete All TasksmediumArrayHash TableGreedyCountingfrequency 26.5
- Most Common WordeasyArrayHash TableStringCountingfrequency 26.5
- Most Frequent Subtree SummediumHash TableTreeDepth-First SearchBinary Tree+1frequency 26.5
- My Calendar ImediumArrayBinary SearchDesignSegment Tree+1frequency 26.5
- Network Delay TimemediumDepth-First SearchBreadth-First SearchGraph TheoryHeap (Priority Queue)+2frequency 26.5
- Number of Ways to Select BuildingsmediumStringDynamic ProgrammingPrefix Sumfrequency 26.5
- Number of Ways to Split ArraymediumArrayPrefix Sumfrequency 26.5
- Sales Analysis IIIeasyDatabasefrequency 26.5
- Shortest Path with Alternating ColorsmediumBreadth-First SearchGraph Theoryfrequency 26.5
- Shortest Subarray to be Removed to Make Array SortedmediumArrayTwo PointersBinary SearchStack+1frequency 26.5
- Single Number IIImediumArrayBit Manipulationfrequency 26.5
- Smallest Number in Infinite SetmediumHash TableDesignHeap (Priority Queue)Ordered Setfrequency 26.5
- Sort Array By Parity IIeasyArrayTwo PointersSortingfrequency 26.5
- Substring Matching PatterneasyStringString Matchingfrequency 26.5
- Sum Root to Leaf NumbersmediumTreeDepth-First SearchBinary Treefrequency 26.5
- Total Appeal of A StringhardHash TableStringDynamic Programmingfrequency 26.5
- Triangle JudgementeasyDatabasefrequency 26.5
- Trionic Array IeasyArrayfrequency 26.5
- User Activity for the Past 30 Days IeasyDatabasefrequency 26.5
- Valid NumberhardStringfrequency 26.5
- All Paths From Source to TargetmediumBacktrackingDepth-First SearchBreadth-First SearchGraph Theory+1frequency 25.1
- Binary Tree Preorder TraversaleasyStackTreeDepth-First SearchBinary Treefrequency 25.1
- Bulls and CowsmediumHash TableStringCountingfrequency 25.1
- Check If Array Pairs Are Divisible by kmediumArrayHash TableCountingfrequency 25.1
- Concatenation of Consecutive Binary NumbersmediumMathBit ManipulationSimulationfrequency 25.1
- Convert BST to Greater TreemediumTreeDepth-First SearchBinary Search TreeBinary Treefrequency 25.1
- Count Stepping Numbers in RangehardStringDynamic Programmingfrequency 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.