23.Merge k Sorted Lists
HardDivide and ConquerHeap (Priority Queue)Linked List60.3% acceptance50 companiesVideo
Hard · With video · 74 results
218.The Skyline Problem
HardArrayBinary Indexed TreeDivide and Conquer45.7% acceptance13 companiesVideo
239.Sliding Window Maximum
HardArrayHeap (Priority Queue)Monotonic Queue49.1% acceptance48 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
358.Rearrange String k Distance Apart
HardCountingGreedyHash Table39.9% acceptance4 companiesPremium elsewhere, free hereVideo
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
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
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
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
759.Employee Free Time
HardArrayHeap (Priority Queue)Sorting72.9% acceptance12 companiesPremium elsewhere, free hereVideo
778.Swim in Rising Water
HardArrayBinary SearchBreadth-First Search68.3% acceptance8 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
1168.Optimize Water Distribution in a Village
HardGraphHeap (Priority Queue)Minimum Spanning Tree65.5% acceptance2 companiesPremium elsewhere, free hereVideo
1172.Dinner Plate Stacks
HardDesignHash TableHeap (Priority Queue)34.2% acceptance2 companiesVideo
1183.Maximum Number of Ones
HardGreedyHeap (Priority Queue)70.6% acceptance1 companyPremium elsewhere, free hereVideo
1199.Minimum Time to Build Blocks
HardArrayGreedyHeap (Priority Queue)49.2% acceptance1 companyPremium elsewhere, free hereVideo
1263.Minimum Moves to Move a Box to Their Target Location
HardArrayBreadth-First SearchHeap (Priority Queue)49.7% acceptance1 companyVideo
1354.Construct Target Array With Multiple Sums
HardArrayHeap (Priority Queue)36.8% acceptance1 companyVideo
1368.Minimum Cost to Make at Least One Valid Path in a Grid
HardArrayBreadth-First SearchGraph70.9% acceptance8 companiesVideo
1383.Maximum Performance of a Team
HardArrayGreedyHeap (Priority Queue)48.2% acceptance7 companiesVideo
1388.Pizza With 3n Slices
HardArrayDynamic ProgrammingGreedy54.4% acceptance1 companyVideo
1425.Constrained Subsequence Sum
HardArrayDynamic ProgrammingHeap (Priority Queue)56.5% acceptance2 companiesVideo
1439.Find the Kth Smallest Sum of a Matrix With Sorted Rows
HardArrayBinary SearchHeap (Priority Queue)62.6% acceptance2 companiesVideo
1499.Max Value of Equation
HardArrayHeap (Priority Queue)Monotonic Queue45.0% acceptance1 companyVideo
1606.Find Servers That Handled Most Number of Requests
HardArrayGreedyHeap (Priority Queue)45.9% acceptance6 companiesVideo
1675.Minimize Deviation in Array
HardArrayGreedyHeap (Priority Queue)54.0% acceptance1 companyVideo
1687.Delivering Boxes from Storage to Ports
HardArrayDynamic ProgrammingHeap (Priority Queue)40.1% acceptance1 companyVideo
1776.Car Fleet II
HardArrayHeap (Priority Queue)Math58.4% acceptance3 companiesVideo
1825.Finding MK Average
HardData StreamDesignHeap (Priority Queue)38.7% acceptance1 companyVideo
1851.Minimum Interval to Include Each Query
HardArrayBinary SearchHeap (Priority Queue)55.4% acceptance3 companiesVideo
1912.Design Movie Rental System
HardArrayDesignHash Table62.5% acceptance2 companiesVideo
2102.Sequentially Ordinal Rank Tracker
HardData StreamDesignHeap (Priority Queue)61.5% acceptance1 companyVideo
2163.Minimum Difference in Sums After Removal of Elements
HardArrayDynamic ProgrammingHeap (Priority Queue)69.8% acceptance7 companiesVideo
2290.Minimum Obstacle Removal to Reach Corner
HardArrayBreadth-First SearchGraph71.1% acceptance2 companiesVideo
2344.Minimum Deletions to Make Array Divisible
HardArrayHeap (Priority Queue)Math61.8% acceptance3 companiesVideo
2386.Find the K-Sum of an Array
HardArrayHeap (Priority Queue)Sorting42.0% acceptance3 companiesVideo
2398.Maximum Number of Robots Within Budget
HardArrayBinary SearchHeap (Priority Queue)39.4% acceptance2 companiesVideo
2402.Meeting Rooms III
HardArrayHash TableHeap (Priority Queue)51.6% acceptance12 companiesVideo
2454.Next Greater Element IV
HardArrayBinary SearchHeap (Priority Queue)43.0% acceptance1 companyVideo
2503.Maximum Number of Points From Grid Queries
HardArrayBreadth-First SearchHeap (Priority Queue)59.3% acceptance6 companiesVideo
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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.