23.Merge k Sorted Lists
HardDivide and ConquerHeap (Priority Queue)Linked List60.3% acceptance50 companiesVideo
208 results
215.Kth Largest Element in an Array
MediumArrayDivide and ConquerHeap (Priority Queue)69.4% acceptance41 companiesVideo
218.The Skyline Problem
HardArrayBinary Indexed TreeDivide and Conquer45.7% acceptance13 companiesVideo
239.Sliding Window Maximum
HardArrayHeap (Priority Queue)Monotonic Queue49.1% acceptance48 companiesVideo
253.Meeting Rooms II
MediumArrayGreedyHeap (Priority Queue)52.6% acceptance42 companiesPremium elsewhere, free hereVideo
264.Ugly Number II
MediumDynamic ProgrammingHash TableHeap (Priority Queue)49.7% acceptance9 companiesVideo
272.Closest Binary Search Tree Value II
HardBinary Search TreeBinary TreeDepth-First Search61.1% acceptance3 companiesPremium elsewhere, free hereVideo
295.Find Median from Data Stream
HardData StreamDesignHeap (Priority Queue)54.9% acceptance40 companiesVideo
347.Top K Frequent Elements
MediumArrayBucket SortCounting67.3% acceptance53 companiesVideo
355.Design Twitter
MediumDesignHash TableHeap (Priority Queue)45.6% acceptance14 companiesVideo
358.Rearrange String k Distance Apart
HardCountingGreedyHash Table39.9% acceptance4 companiesPremium elsewhere, free hereVideo
373.Find K Pairs with Smallest Sums
MediumArrayHeap (Priority Queue)42.3% acceptance10 companiesVideo
378.Kth Smallest Element in a Sorted Matrix
MediumArrayBinary SearchHeap (Priority Queue)65.1% acceptance10 companiesVideo
407.Trapping Rain Water II
HardArrayBreadth-First SearchHeap (Priority Queue)64.0% acceptance14 companiesVideo
420.Strong Password Checker
HardGreedyHeap (Priority Queue)String16.7% acceptance7 companiesVideo
451.Sort Characters By Frequency
MediumBucket SortCountingHash Table75.8% acceptance16 companiesVideo
480.Sliding Window Median
HardArrayHash TableHeap (Priority Queue)38.7% acceptance11 companiesVideo
499.The Maze III
HardArrayBreadth-First SearchDepth-First Search52.3% acceptance1 companyPremium elsewhere, free hereVideo
502.IPO
HardArrayGreedyHeap (Priority Queue)53.6% acceptance9 companiesVideo
505.The Maze II
MediumArrayBreadth-First SearchDepth-First Search55.0% acceptance5 companiesPremium elsewhere, free hereVideo
506.Relative Ranks
EasyArrayHeap (Priority Queue)Sorting75.1% acceptance4 companiesVideo
621.Task Scheduler
MediumArrayCountingGreedy64.0% acceptance24 companiesVideo
630.Course Schedule III
HardArrayGreedyHeap (Priority Queue)42.1% acceptance4 companiesVideo
632.Smallest Range Covering Elements from K Lists
HardArrayGreedyHash Table70.3% acceptance10 companiesVideo
642.Design Search Autocomplete System
HardData StreamDepth-First SearchDesign49.9% acceptance12 companiesPremium elsewhere, free hereVideo
658.Find K Closest Elements
MediumArrayBinary SearchHeap (Priority Queue)50.1% acceptance18 companiesVideo
659.Split Array into Consecutive Subsequences
MediumArrayGreedyHash Table52.7% acceptance2 companiesVideo
675.Cut Off Trees for Golf Event
HardArrayBreadth-First SearchHeap (Priority Queue)36.8% acceptance2 companiesVideo
683.K Empty Slots
HardArrayBinary Indexed TreeHeap (Priority Queue)38.0% acceptance1 companyPremium elsewhere, free hereVideo
692.Top K Frequent Words
MediumBucket SortCountingHash Table60.6% acceptance23 companiesVideo
703.Kth Largest Element in a Stream
EasyBinary Search TreeBinary TreeData Stream61.4% acceptance11 companiesVideo
743.Network Delay Time
MediumBreadth-First SearchDepth-First SearchGraph61.7% acceptance9 companiesVideo
759.Employee Free Time
HardArrayHeap (Priority Queue)Sorting72.9% acceptance12 companiesPremium elsewhere, free hereVideo
767.Reorganize String
MediumCountingGreedyHash Table57.5% acceptance20 companiesVideo
778.Swim in Rising Water
HardArrayBinary SearchBreadth-First Search68.3% acceptance8 companiesVideo
786.K-th Smallest Prime Fraction
MediumArrayBinary SearchHeap (Priority Queue)69.0% acceptance1 companyVideo
787.Cheapest Flights Within K Stops
MediumBreadth-First SearchDepth-First SearchDynamic Programming42.7% acceptance18 companiesVideo
855.Exam Room
MediumDesignHeap (Priority Queue)Ordered Set43.6% acceptance6 companiesVideo
857.Minimum Cost to Hire K Workers
HardArrayGreedyHeap (Priority Queue)63.5% acceptance3 companiesVideo
862.Shortest Subarray with Sum at Least K
HardArrayBinary SearchHeap (Priority Queue)33.3% acceptance7 companiesVideo
871.Minimum Number of Refueling Stops
HardArrayDynamic ProgrammingGreedy41.8% acceptance7 companiesVideo
882.Reachable Nodes In Subdivided Graph
HardGraphHeap (Priority Queue)Shortest Path53.1% acceptance2 companiesVideo
912.Sort an Array
MediumArrayBucket SortCounting Sort55.9% acceptance12 companiesVideo
973.K Closest Points to Origin
MediumArrayDivide and ConquerGeometry69.4% acceptance17 companiesVideo
1046.Last Stone Weight
EasyArrayHeap (Priority Queue)66.4% acceptance13 companiesVideo
1054.Distant Barcodes
MediumArrayCountingGreedy49.3% acceptance2 companiesVideo
1086.High Five
EasyArrayHash TableHeap (Priority Queue)74.5% acceptance2 companiesPremium elsewhere, free hereVideo
1094.Car Pooling
MediumArrayHeap (Priority Queue)Prefix Sum56.5% acceptance12 companiesVideo
1102.Path With Maximum Minimum Value
MediumArrayBinary SearchBreadth-First Search54.6% acceptance3 companiesPremium elsewhere, free hereVideo
1135.Connecting Cities With Minimum Cost
MediumGraphHeap (Priority Queue)Minimum Spanning Tree63.5% acceptance1 companyPremium elsewhere, free hereVideo
Showing 1–50 of 208
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.