5.Longest Palindromic Substring
MediumDynamic ProgrammingStringTwo Pointers38.7% acceptance81 companiesVideo
Medium · 146 results
11.Container With Most Water
MediumArrayGreedyTwo Pointers60.9% acceptance57 companiesVideo
15.3Sum
MediumArraySortingTwo Pointers40.1% acceptance57 companiesVideo
16.3Sum Closest
MediumArraySortingTwo Pointers47.4% acceptance11 companiesVideo
18.4Sum
MediumArraySortingTwo Pointers42.0% acceptance20 companiesVideo
19.Remove Nth Node From End of List
MediumLinked ListTwo Pointers52.4% acceptance18 companiesVideo
31.Next Permutation
MediumArrayTwo Pointers46.1% acceptance31 companiesVideo
61.Rotate List
MediumLinked ListTwo Pointers43.1% acceptance9 companiesVideo
75.Sort Colors
MediumArraySortingTwo Pointers69.9% acceptance37 companiesVideo
80.Remove Duplicates from Sorted Array II
MediumArrayTwo Pointers65.0% acceptance9 companiesVideo
82.Remove Duplicates from Sorted List II
MediumLinked ListTwo Pointers52.8% acceptance11 companiesVideo
86.Partition List
MediumLinked ListTwo Pointers62.0% acceptance5 companiesVideo
142.Linked List Cycle II
MediumHash TableLinked ListTwo Pointers59.3% acceptance13 companiesVideo
143.Reorder List
MediumLinked ListRecursionStack66.6% acceptance15 companiesVideo
148.Sort List
MediumDivide and ConquerLinked ListMerge Sort65.2% acceptance9 companiesVideo
151.Reverse Words in a String
MediumStringTwo Pointers57.8% acceptance30 companiesVideo
161.One Edit Distance
MediumStringTwo Pointers34.4% acceptance8 companiesPremium elsewhere, free hereVideo
165.Compare Version Numbers
MediumStringTwo Pointers46.8% acceptance11 companiesVideo
167.Two Sum II - Input Array Is Sorted
MediumArrayBinary SearchTwo Pointers66.1% acceptance16 companiesVideo
186.Reverse Words in a String II
MediumStringTwo Pointers56.6% acceptance4 companiesPremium elsewhere, free hereVideo
189.Rotate Array
MediumArrayMathTwo Pointers45.3% acceptance27 companiesVideo
244.Shortest Word Distance II
MediumArrayDesignHash Table62.8% acceptance4 companiesPremium elsewhere, free hereVideo
251.Flatten 2D Vector
MediumArrayDesignIterator50.5% acceptance4 companiesPremium elsewhere, free hereVideo
253.Meeting Rooms II
MediumArrayGreedyHeap (Priority Queue)52.6% acceptance42 companiesPremium elsewhere, free hereVideo
259.3Sum Smaller
MediumArrayBinary SearchSorting51.4% acceptance7 companiesPremium elsewhere, free hereVideo
277.Find the Celebrity
MediumGraphInteractiveTwo Pointers48.9% acceptance12 companiesPremium elsewhere, free hereVideo
287.Find the Duplicate Number
MediumArrayBinary SearchBit Manipulation64.7% acceptance22 companiesVideo
360.Sort Transformed Array
MediumArrayMathSorting58.0% acceptance3 companiesPremium elsewhere, free hereVideo
443.String Compression
MediumStringTwo Pointers60.9% acceptance41 companiesVideo
457.Circular Array Loop
MediumArrayHash TableTwo Pointers38.3% acceptance4 companiesVideo
475.Heaters
MediumArrayBinary SearchSorting42.9% acceptance12 companiesVideo
481.Magical String
MediumStringTwo Pointers56.6% acceptance3 companiesVideo
522.Longest Uncommon Subsequence II
MediumArrayHash TableSorting45.8% acceptance1 companyVideo
524.Longest Word in Dictionary through Deleting
MediumArraySortingString53.2% acceptance2 companiesVideo
532.K-diff Pairs in an Array
MediumArrayBinary SearchHash Table46.3% acceptance8 companiesVideo
556.Next Greater Element III
MediumMathStringTwo Pointers35.2% acceptance11 companiesVideo
567.Permutation in String
MediumHash TableSliding WindowString49.8% acceptance16 companiesVideo
581.Shortest Unsorted Continuous Subarray
MediumArrayGreedyMonotonic Stack38.7% acceptance9 companiesVideo
611.Valid Triangle Number
MediumArrayBinary SearchGreedy57.4% acceptance9 companiesVideo
633.Sum of Square Numbers
MediumBinary SearchMathTwo Pointers37.0% acceptance6 companiesVideo
647.Palindromic Substrings
MediumDynamic ProgrammingStringTwo Pointers73.2% acceptance25 companiesVideo
658.Find K Closest Elements
MediumArrayBinary SearchHeap (Priority Queue)50.1% acceptance18 companiesVideo
723.Candy Crush
MediumArrayMatrixSimulation77.6% acceptance11 companiesPremium elsewhere, free hereVideo
763.Partition Labels
MediumGreedyHash TableString81.8% acceptance9 companiesVideo
777.Swap Adjacent in LR String
MediumStringTwo Pointers38.5% acceptance3 companiesVideo
786.K-th Smallest Prime Fraction
MediumArrayBinary SearchHeap (Priority Queue)69.0% acceptance1 companyVideo
795.Number of Subarrays with Bounded Maximum
MediumArrayTwo Pointers55.4% acceptance4 companiesVideo
809.Expressive Words
MediumArrayStringTwo Pointers46.8% acceptance2 companiesVideo
825.Friends Of Appropriate Ages
MediumArrayBinary SearchSorting49.9% acceptance3 companiesVideo
826.Most Profit Assigning Work
MediumArrayBinary SearchGreedy56.4% acceptance5 companiesVideo
Showing 1–50 of 146
How to use these solutions
Each solution breaks the problem into approaches, usually from brute force to the best one, and explains why each works. Code comes in Python, Java, C++ and other languages. Knowing why an approach works matters more in an interview than remembering the code.
- Try the problem first. Give it at least 20 minutes before you open the solution.
- Read every approach. The brute force shows you the problem; the faster ones show the pattern.
- Check the complexity. Note the time and space of each approach and what makes the difference.
- Write it yourself. Close the solution and code it from memory in the editor.
- Come back in a week. Solving it again later is what makes the pattern stick.