669.Trim a Binary Search Tree
MediumBinary Search TreeBinary TreeDepth-First Search66.9% acceptance4 companiesVideo
With video · 318 results
671.Second Minimum Node In a Binary Tree
EasyBinary TreeDepth-First SearchTree46.0% acceptance2 companiesVideo
672.Bulb Switcher II
MediumBit ManipulationBreadth-First SearchDepth-First Search51.2% acceptance1 companyVideo
676.Implement Magic Dictionary
MediumDepth-First SearchDesignHash Table58.4% acceptance2 companiesVideo
684.Redundant Connection
MediumBreadth-First SearchDepth-First SearchGraph68.0% acceptance8 companiesVideo
685.Redundant Connection II
HardBreadth-First SearchDepth-First SearchGraph36.6% acceptance1 companyVideo
687.Longest Univalue Path
MediumBinary TreeDepth-First SearchTree44.3% acceptance7 companiesVideo
690.Employee Importance
MediumArrayBreadth-First SearchDepth-First Search69.4% acceptance6 companiesVideo
694.Number of Distinct Islands
MediumBreadth-First SearchDepth-First SearchHash Function62.8% acceptance12 companiesPremium elsewhere, free hereVideo
695.Max Area of Island
MediumArrayBreadth-First SearchDepth-First Search73.9% acceptance20 companiesVideo
711.Number of Distinct Islands II
HardBreadth-First SearchDepth-First SearchHash Function55.3% acceptance2 companiesPremium elsewhere, free hereVideo
721.Accounts Merge
MediumArrayBreadth-First SearchDepth-First Search62.2% acceptance17 companiesVideo
733.Flood Fill
EasyArrayBreadth-First SearchDepth-First Search68.6% acceptance12 companiesVideo
737.Sentence Similarity II
MediumArrayBreadth-First SearchDepth-First Search51.2% acceptance4 companiesPremium elsewhere, free hereVideo
742.Closest Leaf in a Binary Tree
MediumBinary TreeBreadth-First SearchDepth-First Search47.4% acceptance3 companiesPremium elsewhere, free hereVideo
743.Network Delay Time
MediumBreadth-First SearchDepth-First SearchGraph61.7% acceptance9 companiesVideo
749.Contain Virus
HardArrayBreadth-First SearchDepth-First Search56.5% acceptance3 companiesVideo
753.Cracking the Safe
HardDepth-First SearchEulerian CircuitGraph58.5% acceptance1 companyVideo
756.Pyramid Transition Matrix
MediumBit ManipulationBreadth-First SearchDepth-First Search60.6% acceptance3 companiesVideo
765.Couples Holding Hands
HardBreadth-First SearchDepth-First SearchGraph59.8% acceptance5 companiesVideo
778.Swim in Rising Water
HardArrayBinary SearchBreadth-First Search68.3% acceptance8 companiesVideo
783.Minimum Distance Between BST Nodes
EasyBinary Search TreeBinary TreeBreadth-First Search61.8% acceptance4 companiesVideo
785.Is Graph Bipartite?
MediumBreadth-First SearchDepth-First SearchGraph59.6% acceptance11 companiesVideo
787.Cheapest Flights Within K Stops
MediumBreadth-First SearchDepth-First SearchDynamic Programming42.7% acceptance18 companiesVideo
797.All Paths From Source to Target
MediumBacktrackingBreadth-First SearchDepth-First Search83.6% acceptance5 companiesVideo
802.Find Eventual Safe States
MediumBreadth-First SearchDepth-First SearchGraph71.6% acceptance7 companiesVideo
814.Binary Tree Pruning
MediumBinary TreeDepth-First SearchTree72.3% acceptance5 companiesVideo
827.Making A Large Island
HardArrayBreadth-First SearchDepth-First Search57.0% acceptance16 companiesVideo
834.Sum of Distances in Tree
HardDepth-First SearchDynamic ProgrammingGraph65.8% acceptance5 companiesVideo
839.Similar String Groups
HardArrayBreadth-First SearchDepth-First Search56.7% acceptance5 companiesVideo
841.Keys and Rooms
MediumBreadth-First SearchDepth-First SearchGraph76.2% acceptance10 companiesVideo
851.Loud and Rich
MediumArrayDepth-First SearchGraph63.9% acceptance6 companiesVideo
863.All Nodes Distance K in Binary Tree
MediumBinary TreeBreadth-First SearchDepth-First Search68.1% acceptance16 companiesVideo
865.Smallest Subtree with all the Deepest Nodes
MediumBinary TreeBreadth-First SearchDepth-First Search77.5% acceptance4 companiesVideo
872.Leaf-Similar Trees
EasyBinary TreeDepth-First SearchTree70.0% acceptance5 companiesVideo
886.Possible Bipartition
MediumBreadth-First SearchDepth-First SearchGraph53.0% acceptance11 companiesVideo
897.Increasing Order Search Tree
EasyBinary Search TreeBinary TreeDepth-First Search79.1% acceptance2 companiesVideo
924.Minimize Malware Spread
HardArrayBreadth-First SearchDepth-First Search43.6% acceptance10 companiesVideo
928.Minimize Malware Spread II
HardArrayBreadth-First SearchDepth-First Search46.2% acceptance2 companiesVideo
934.Shortest Bridge
MediumArrayBreadth-First SearchDepth-First Search59.9% acceptance16 companiesVideo
938.Range Sum of BST
EasyBinary Search TreeBinary TreeDepth-First Search87.7% acceptance6 companiesVideo
947.Most Stones Removed with Same Row or Column
MediumDepth-First SearchGraphHash Table63.4% acceptance10 companiesVideo
951.Flip Equivalent Binary Trees
MediumBinary TreeDepth-First SearchTree69.8% acceptance4 companiesVideo
959.Regions Cut By Slashes
MediumArrayBreadth-First SearchDepth-First Search77.8% acceptance6 companiesVideo
965.Univalued Binary Tree
EasyBinary TreeBreadth-First SearchDepth-First Search73.5% acceptance3 companiesVideo
968.Binary Tree Cameras
HardBinary TreeDepth-First SearchDynamic Programming48.3% acceptance14 companiesVideo
971.Flip Binary Tree To Match Preorder Traversal
MediumBinary TreeDepth-First SearchTree51.9% acceptanceVideo
979.Distribute Coins in Binary Tree
MediumBinary TreeDepth-First SearchTree77.2% acceptance8 companiesVideo
987.Vertical Order Traversal of a Binary Tree
HardBinary TreeBreadth-First SearchDepth-First Search54.6% acceptance15 companiesVideo
988.Smallest String Starting From Leaf
MediumBacktrackingBinary TreeDepth-First Search61.2% acceptance2 companiesVideo
Showing 101–150 of 318
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.