Solutions & Explanations

Browse 4,029+ detailed solutions with multiple approaches, code in Python, Java, C++ and more.

4,029 Solutions961 Easy2102 Medium966 Hard

Title	Difficulty	Acceptance	Topics	Solution
807. Max Increase to Keep City Skyline	Medium	86.2%	Array Greedy+1	Read
808. Soup Servings	Medium	59.7%	Dynamic Programming Math+1	Read
809. Expressive Words	Medium	46.8%	Array String+1	Read
811. Subdomain Visit Count	Medium	77.2%	Array Counting+2	Read
813. Largest Sum of Averages	Medium	55.5%	Array Dynamic Programming+1	Read
814. Binary Tree Pruning	Medium	72.3%	Binary Tree Depth-First Search+1	Read
816. Ambiguous Coordinates	Medium	56.4%	Backtracking Enumeration+1	Read
817. Linked List Components	Medium	57.8%	Array Hash Table+1	Read
820. Short Encoding of Words	Medium	61.0%	Array Hash Table+2	Read
822. Card Flipping Game	Medium	50.7%	Array Hash Table	Read
823. Binary Trees With Factors	Medium	52.9%	Array Dynamic Programming+2	Read
825. Friends Of Appropriate Ages	Medium	49.9%	Array Binary Search+2	Read
826. Most Profit Assigning Work	Medium	56.4%	Array Binary Search+3	Read
831. Masking Personal Information	Medium	56.2%	String	Read
833. Find And Replace in String	Medium	50.9%	Array Hash Table+2	Read
835. Image Overlap	Medium	70.6%	Array Matrix	Read
837. New 21 Game	Medium	52.0%	Dynamic Programming Math+2	Read
838. Push Dominoes	Medium	63.0%	Dynamic Programming String+1	Read
840. Magic Squares In Grid	Medium	55.1%	Array Hash Table+2	Read
841. Keys and Rooms	Medium	76.2%	Breadth-First Search Depth-First Search+1	Read
842. Split Array into Fibonacci Sequence	Medium	40.3%	Backtracking String	Read
845. Longest Mountain in Array	Medium	42.0%	Array Dynamic Programming+2	Read
846. Hand of Straights	Medium	57.9%	Array Greedy+2	Read
848. Shifting Letters	Medium	46.1%	Array Prefix Sum+1	Read
849. Maximize Distance to Closest Person	Medium	49.7%	Array	Read
851. Loud and Rich	Medium	63.9%	Array Depth-First Search+2	Read
852. Peak Index in a Mountain Array	Medium	66.9%	Array Binary Search	Read
853. Car Fleet	Medium	55.5%	Array Monotonic Stack+2	Read
855. Exam Room	Medium	43.6%	Design Heap (Priority Queue)+1	Read
856. Score of Parentheses	Medium	63.9%	Stack String	Read
858. Mirror Reflection	Medium	62.3%	Geometry Math+1	Read
861. Score After Flipping Matrix	Medium	80.3%	Array Bit Manipulation+2	Read
863. All Nodes Distance K in Binary Tree	Medium	68.1%	Binary Tree Breadth-First Search+3	Read
865. Smallest Subtree with all the Deepest Nodes	Medium	77.5%	Binary Tree Breadth-First Search+3	Read
866. Prime Palindrome	Medium	28.6%	Math Number Theory	Read
869. Reordered Power of 2	Medium	66.0%	Counting Enumeration+3	Read
870. Advantage Shuffle	Medium	55.0%	Array Greedy+2	Read
873. Length of Longest Fibonacci Subsequence	Medium	57.5%	Array Dynamic Programming+1	Read
874. Walking Robot Simulation	Medium	64.5%	Array Hash Table+1	Read
875. Koko Eating Bananas	Medium	50.4%	Array Binary Search	Read
877. Stone Game	Medium	77.0%	Array Dynamic Programming+2	Read
880. Decoded String at Index	Medium	37.3%	Stack String	Read
881. Boats to Save People	Medium	62.1%	Array Greedy+2	Read
885. Spiral Matrix III	Medium	84.6%	Array Matrix+1	Read
886. Possible Bipartition	Medium	53.0%	Breadth-First Search Depth-First Search+2	Read
889. Construct Binary Tree from Preorder and Postorder Traversal	Medium	78.0%	Array Binary Tree+3	Read
890. Find and Replace Pattern	Medium	76.8%	Array Hash Table+1	Read
893. Groups of Special-Equivalent Strings	Medium	73.5%	Array Hash Table+2	Read
894. All Possible Full Binary Trees	Medium	82.8%	Binary Tree Dynamic Programming+3	Read
898. Bitwise ORs of Subarrays	Medium	56.8%	Array Bit Manipulation+1	Read

#807Medium

Max Increase to Keep City Skyline

ArrayGreedyMatrix

Acceptance: 86.2%

#808Medium

Soup Servings

Dynamic ProgrammingMathProbability and Statistics

Acceptance: 59.7%

#809Medium

Expressive Words

ArrayStringTwo Pointers

Acceptance: 46.8%

#811Medium

Subdomain Visit Count

ArrayCountingHash Table+1

Acceptance: 77.2%

#813Medium

Largest Sum of Averages

ArrayDynamic ProgrammingPrefix Sum

Acceptance: 55.5%

#814Medium

Binary Tree Pruning

Binary TreeDepth-First SearchTree

Acceptance: 72.3%

#816Medium

Ambiguous Coordinates

BacktrackingEnumerationString

Acceptance: 56.4%

#817Medium

Linked List Components

ArrayHash TableLinked List

Acceptance: 57.8%

#820Medium

Short Encoding of Words

ArrayHash TableString+1

Acceptance: 61.0%

#822Medium

Card Flipping Game

ArrayHash Table

Acceptance: 50.7%

#823Medium

Binary Trees With Factors

ArrayDynamic ProgrammingHash Table+1

Acceptance: 52.9%

#825Medium

Friends Of Appropriate Ages

ArrayBinary SearchSorting+1

Acceptance: 49.9%

#826Medium

Most Profit Assigning Work

ArrayBinary SearchGreedy+2

Acceptance: 56.4%

#831Medium

Masking Personal Information

String

Acceptance: 56.2%

#833Medium

Find And Replace in String

ArrayHash TableSorting+1

Acceptance: 50.9%

#835Medium

Image Overlap

ArrayMatrix

Acceptance: 70.6%

#837Medium

New 21 Game

Dynamic ProgrammingMathProbability and Statistics+1

Acceptance: 52.0%

#838Medium

Push Dominoes

Dynamic ProgrammingStringTwo Pointers

Acceptance: 63.0%

#840Medium

Magic Squares In Grid

ArrayHash TableMath+1

Acceptance: 55.1%

#841Medium

Keys and Rooms

Breadth-First SearchDepth-First SearchGraph

Acceptance: 76.2%

#842Medium

Split Array into Fibonacci Sequence

BacktrackingString

Acceptance: 40.3%

#845Medium

Longest Mountain in Array

ArrayDynamic ProgrammingEnumeration+1

Acceptance: 42.0%

#846Medium

Hand of Straights

ArrayGreedyHash Table+1

Acceptance: 57.9%

#848Medium

Shifting Letters

ArrayPrefix SumString

Acceptance: 46.1%

#849Medium

Maximize Distance to Closest Person

Array

Acceptance: 49.7%

#851Medium

Loud and Rich

ArrayDepth-First SearchGraph+1

Acceptance: 63.9%

#852Medium

Peak Index in a Mountain Array

ArrayBinary Search

Acceptance: 66.9%

#853Medium

Car Fleet

ArrayMonotonic StackSorting+1

Acceptance: 55.5%

#855Medium

Exam Room

DesignHeap (Priority Queue)Ordered Set

Acceptance: 43.6%

#856Medium

Score of Parentheses

StackString

Acceptance: 63.9%

#858Medium

Mirror Reflection

GeometryMathNumber Theory

Acceptance: 62.3%

#861Medium

Score After Flipping Matrix

ArrayBit ManipulationGreedy+1

Acceptance: 80.3%

#863Medium

All Nodes Distance K in Binary Tree

Binary TreeBreadth-First SearchDepth-First Search+2

Acceptance: 68.1%

#865Medium

Smallest Subtree with all the Deepest Nodes

Binary TreeBreadth-First SearchDepth-First Search+2

Acceptance: 77.5%

#866Medium

Prime Palindrome

MathNumber Theory

Acceptance: 28.6%

#869Medium

Reordered Power of 2

CountingEnumerationHash Table+2

Acceptance: 66.0%

#870Medium

Advantage Shuffle

ArrayGreedySorting+1

Acceptance: 55.0%

#873Medium

Length of Longest Fibonacci Subsequence

ArrayDynamic ProgrammingHash Table

Acceptance: 57.5%

#874Medium

Walking Robot Simulation

ArrayHash TableSimulation

Acceptance: 64.5%

#875Medium

Koko Eating Bananas

ArrayBinary Search

Acceptance: 50.4%

#877Medium

Stone Game

ArrayDynamic ProgrammingGame Theory+1

Acceptance: 77.0%

#880Medium

Decoded String at Index

StackString

Acceptance: 37.3%

#881Medium

Boats to Save People

ArrayGreedySorting+1

Acceptance: 62.1%

#885Medium

Spiral Matrix III

ArrayMatrixSimulation

Acceptance: 84.6%

#886Medium

Possible Bipartition

Breadth-First SearchDepth-First SearchGraph+1

Acceptance: 53.0%

#889Medium

Construct Binary Tree from Preorder and Postorder Traversal

ArrayBinary TreeDivide and Conquer+2

Acceptance: 78.0%

#890Medium

Find and Replace Pattern

ArrayHash TableString

Acceptance: 76.8%

#893Medium

Groups of Special-Equivalent Strings

ArrayHash TableSorting+1

Acceptance: 73.5%

#894Medium

All Possible Full Binary Trees

Binary TreeDynamic ProgrammingMemoization+2

Acceptance: 82.8%

#898Medium

Bitwise ORs of Subarrays

ArrayBit ManipulationDynamic Programming

Acceptance: 56.8%

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