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
- Wildcard MatchinghardStringDynamic ProgrammingGreedyRecursionfrequency 37.7
- Cutting RibbonsmediumArrayBinary Searchfrequency 36.8
- Frequency of the Most Frequent ElementmediumArrayBinary SearchGreedySliding Window+2frequency 36.8
- Friend Requests II: Who Has the Most FriendsmediumDatabasefrequency 36.8
- Kth Largest Element in a StreameasyTreeDesignBinary Search TreeHeap (Priority Queue)+2frequency 36.8
- Maximum Sum of 3 Non-Overlapping SubarrayshardArrayDynamic ProgrammingSliding WindowPrefix Sumfrequency 36.8
- Reverse StringeasyTwo PointersStringfrequency 36.8
- Same TreeeasyTreeDepth-First SearchBreadth-First SearchBinary Treefrequency 36.8
- Sort ListmediumLinked ListTwo PointersDivide and ConquerSorting+1frequency 36.8
- Unique Binary Search TreesmediumMathDynamic ProgrammingTreeBinary Search Tree+1frequency 36.8
- Valid Parenthesis StringmediumStringDynamic ProgrammingStackGreedy+1frequency 36.8
- Valid SudokumediumArrayHash TableMatrixfrequency 36.8
- Word Break IIhardArrayHash TableStringDynamic Programming+3frequency 36.8
- Check if Array Is Sorted and RotatedeasyArrayfrequency 36.0
- Gas StationmediumArrayGreedyfrequency 36.0
- Kth Smallest Element in a BSTmediumTreeDepth-First SearchBinary Search TreeBinary Treefrequency 36.0
- Longest Increasing SubsequencemediumArrayBinary SearchDynamic ProgrammingLongest Increasing Subsequencefrequency 36.0
- Search a 2D Matrix IImediumArrayBinary SearchDivide and ConquerMatrixfrequency 36.0
- Second Highest SalarymediumDatabasefrequency 36.0
- Symmetric TreeeasyTreeDepth-First SearchBreadth-First SearchBinary Treefrequency 36.0
- Task SchedulermediumArrayHash TableGreedySorting+2frequency 36.0
- Average Time of Process per MachineeasyDatabasefrequency 35.0
- Combine Two TableseasyDatabasefrequency 35.0
- Greatest Common Divisor of StringseasyMathStringEuclidean AlgorithmGreatest Common Divisorfrequency 35.0
- Kids With the Greatest Number of CandieseasyArrayfrequency 35.0
- Length of Last WordeasyStringfrequency 35.0
- Letter Case PermutationmediumStringBacktrackingBit Manipulationfrequency 35.0
- Lowest Common Ancestor of a Binary Tree IImediumTreeDepth-First SearchBinary TreeBinary Lifting+1frequency 35.0
- Maximum Size Subarray Sum Equals kmediumArrayHash TablePrefix Sumfrequency 35.0
- Monotonic ArrayeasyArrayfrequency 35.0
- Remove K DigitsmediumStringStackGreedyMonotonic Stackfrequency 35.0
- Rotate ListmediumLinked ListTwo Pointersfrequency 35.0
- Sort Array By ParityeasyArrayTwo PointersSortingfrequency 35.0
- Balanced Binary TreeeasyTreeDepth-First SearchBinary Treefrequency 34.0
- Big CountrieseasyDatabasefrequency 34.0
- Edit DistancemediumStringDynamic Programmingfrequency 34.0
- Implement Trie (Prefix Tree)mediumHash TableStringDesignTriefrequency 34.0
- Longest Common SubsequencemediumStringDynamic ProgrammingLongest Common Subsequencefrequency 34.0
- Lowest Common Ancestor of Deepest LeavesmediumHash TableTreeDepth-First SearchBreadth-First Search+4frequency 34.0
- Majority Element IImediumArrayHash TableSortingCounting+1frequency 34.0
- Next Greater Element IIImediumMathTwo PointersStringfrequency 34.0
- Reverse Linked List IImediumLinked Listfrequency 34.0
- Rotate StringeasyStringString Matchingfrequency 34.0
- Binary Tree PathseasyStringBacktrackingTreeDepth-First Search+1frequency 33.0
- CandyhardArrayGreedyfrequency 33.0
- Count PrimesmediumArrayMathEnumerationNumber Theory+3frequency 33.0
- Delete Node in a Linked ListmediumLinked Listfrequency 33.0
- Find All Anagrams in a StringmediumHash TableStringSliding Windowfrequency 33.0
- Flatten Binary Tree to Linked ListmediumLinked ListStackTreeDepth-First Search+1frequency 33.0
- Integer to English WordshardMathStringRecursionfrequency 33.0
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.