Solutions & Explanations

Browse 4,030+ detailed solutions with multiple approaches, code in Python, Java, C++ and more.

4,030 Solutions961 Easy2102 Medium967 Hard

Title	Difficulty	Acceptance	Topics	Solution
1901. Find a Peak Element II	Medium	55.7%	Array Binary Search+1	Read
1902. Depth of BST Given Insertion Order	Medium	42.5%	Array Binary Search Tree+3	Read
1903. Largest Odd Number in String	Easy	67.7%	Greedy Math+1	Read
1904. The Number of Full Rounds You Have Played	Medium	43.9%	Math String	Read
1905. Count Sub Islands	Medium	72.8%	Array Breadth-First Search+3	Read
1906. Minimum Absolute Difference Queries	Medium	45.8%	Array Hash Table	Read
1907. Count Salary Categories	Medium	62.5%	Database	Read
1908. Game of Nim	Medium	62.4%	Array Bit Manipulation+4	Read
1909. Remove One Element to Make the Array Strictly Increasing	Easy	30.8%	Array	Read
1910. Remove All Occurrences of a Substring	Medium	78.2%	Simulation Stack+1	Read
1911. Maximum Alternating Subsequence Sum	Medium	58.8%	Array Dynamic Programming	Read
1912. Design Movie Rental System	Hard	62.5%	Array Design+3	Read
1913. Maximum Product Difference Between Two Pairs	Easy	82.9%	Array Sorting	Read
1914. Cyclically Rotating a Grid	Medium	74.2%	Array Matrix+1	Read
1915. Number of Wonderful Substrings	Medium	66.8%	Bit Manipulation Hash Table+2	Read
1916. Count Ways to Build Rooms in an Ant Colony	Hard	51.8%	Combinatorics Dynamic Programming+4	Read
1917. Leetcodify Friends Recommendations	Hard	27.5%	Database	Read
1918. Kth Smallest Subarray Sum	Medium	53.4%	Array Binary Search+1	Read
1919. Leetcodify Similar Friends	Hard	42.4%	Database	Read
1920. Build Array from Permutation	Easy	91.1%	Array Simulation	Read
1921. Eliminate Maximum Number of Monsters	Medium	50.9%	Array Greedy+1	Read
1922. Count Good Numbers	Medium	58.1%	Math Recursion	Read
1923. Longest Common Subpath	Hard	30.1%	Array Binary Search+3	Read
1924. Erect the Fence II	Hard	49.4%	Array Geometry+1	Read
1925. Count Square Sum Triples	Easy	77.2%	Enumeration Math	Read
1926. Nearest Exit from Entrance in Maze	Medium	49.0%	Array Breadth-First Search+1	Read
1927. Sum Game	Medium	63.5%	Game Theory Greedy+2	Read
1928. Minimum Cost to Reach Destination in Time	Hard	42.0%	Array Dynamic Programming+1	Read
1929. Concatenation of Array	Easy	90.2%	Array Simulation	Read
1930. Unique Length-3 Palindromic Subsequences	Medium	73.8%	Bit Manipulation Hash Table+2	Read
1931. Painting a Grid With Three Different Colors	Hard	77.2%	Dynamic Programming	Read
1932. Merge BSTs to Create Single BST	Hard	39.7%	Binary Search Binary Tree+3	Read
1933. Check if String Is Decomposable Into Value-Equal Substrings	Easy	50.4%	String	Read
1934. Confirmation Rate	Medium	60.1%	Database	Read
1935. Maximum Number of Words You Can Type	Easy	82.9%	Hash Table String	Read
1936. Add Minimum Number of Rungs	Medium	43.8%	Array Greedy	Read
1937. Maximum Number of Points with Cost	Medium	41.8%	Array Dynamic Programming+1	Read
1938. Maximum Genetic Difference Query	Hard	48.0%	Array Bit Manipulation+3	Read
1939. Users That Actively Request Confirmation Messages	Easy	56.4%	Database	Read
1940. Longest Common Subsequence Between Sorted Arrays	Medium	81.3%	Array Counting+1	Read
1941. Check if All Characters Have Equal Number of Occurrences	Easy	79.4%	Counting Hash Table+1	Read
1942. The Number of the Smallest Unoccupied Chair	Medium	60.3%	Array Hash Table+1	Read
1943. Describe the Painting	Medium	52.7%	Array Hash Table+2	Read
1944. Number of Visible People in a Queue	Hard	73.3%	Array Monotonic Stack+1	Read
1945. Sum of Digits of String After Convert	Easy	74.9%	Simulation String	Read
1946. Largest Number After Mutating Substring	Medium	38.5%	Array Greedy+1	Read
1947. Maximum Compatibility Score Sum	Medium	65.0%	Array Backtracking+3	Read
1948. Delete Duplicate Folders in System	Hard	77.7%	Array Hash Function+3	Read
1949. Strong Friendship	Medium	54.6%	Database	Read
1950. Maximum of Minimum Values in All Subarrays	Medium	48.0%	Array Monotonic Stack+1	Read

#1901Medium

Find a Peak Element II

ArrayBinary SearchMatrix

Acceptance: 55.7%

#1902Medium

Depth of BST Given Insertion Order

ArrayBinary Search TreeBinary Tree+2

Acceptance: 42.5%

#1903Easy

Largest Odd Number in String

GreedyMathString

Acceptance: 67.7%

#1904Medium

The Number of Full Rounds You Have Played

MathString

Acceptance: 43.9%

#1905Medium

Count Sub Islands

ArrayBreadth-First SearchDepth-First Search+2

Acceptance: 72.8%

#1906Medium

Minimum Absolute Difference Queries

ArrayHash Table

Acceptance: 45.8%

#1907Medium

Count Salary Categories

Database

Acceptance: 62.5%

#1908Medium

Game of Nim

ArrayBit ManipulationBrainteaser+3

Acceptance: 62.4%

#1909Easy

Remove One Element to Make the Array Strictly Increasing

Array

Acceptance: 30.8%

#1910Medium

Remove All Occurrences of a Substring

SimulationStackString

Acceptance: 78.2%

#1911Medium

Maximum Alternating Subsequence Sum

ArrayDynamic Programming

Acceptance: 58.8%

#1912Hard

Design Movie Rental System

ArrayDesignHash Table+2

Acceptance: 62.5%

#1913Easy

Maximum Product Difference Between Two Pairs

ArraySorting

Acceptance: 82.9%

#1914Medium

Cyclically Rotating a Grid

ArrayMatrixSimulation

Acceptance: 74.2%

#1915Medium

Number of Wonderful Substrings

Bit ManipulationHash TablePrefix Sum+1

Acceptance: 66.8%

#1916Hard

Count Ways to Build Rooms in an Ant Colony

CombinatoricsDynamic ProgrammingGraph+3

Acceptance: 51.8%

#1917Hard

Leetcodify Friends Recommendations

Database

Acceptance: 27.5%

#1918Medium

Kth Smallest Subarray Sum

ArrayBinary SearchSliding Window

Acceptance: 53.4%

#1919Hard

Leetcodify Similar Friends

Database

Acceptance: 42.4%

#1920Easy

Build Array from Permutation

ArraySimulation

Acceptance: 91.1%

#1921Medium

Eliminate Maximum Number of Monsters

ArrayGreedySorting

Acceptance: 50.9%

#1922Medium

Count Good Numbers

MathRecursion

Acceptance: 58.1%

#1923Hard

Longest Common Subpath

ArrayBinary SearchHash Function+2

Acceptance: 30.1%

#1924Hard

Erect the Fence II

ArrayGeometryMath

Acceptance: 49.4%

#1925Easy

Count Square Sum Triples

EnumerationMath

Acceptance: 77.2%

#1926Medium

Nearest Exit from Entrance in Maze

ArrayBreadth-First SearchMatrix

Acceptance: 49.0%

#1927Medium

Sum Game

Game TheoryGreedyMath+1

Acceptance: 63.5%

#1928Hard

Minimum Cost to Reach Destination in Time

ArrayDynamic ProgrammingGraph

Acceptance: 42.0%

#1929Easy

Concatenation of Array

ArraySimulation

Acceptance: 90.2%

#1930Medium

Unique Length-3 Palindromic Subsequences

Bit ManipulationHash TablePrefix Sum+1

Acceptance: 73.8%

#1931Hard

Painting a Grid With Three Different Colors

Dynamic Programming

Acceptance: 77.2%

#1932Hard

Merge BSTs to Create Single BST

Binary SearchBinary TreeDepth-First Search+2

Acceptance: 39.7%

#1933Easy

Check if String Is Decomposable Into Value-Equal Substrings

String

Acceptance: 50.4%

#1934Medium

Confirmation Rate

Database

Acceptance: 60.1%

#1935Easy

Maximum Number of Words You Can Type

Hash TableString

Acceptance: 82.9%

#1936Medium

Add Minimum Number of Rungs

ArrayGreedy

Acceptance: 43.8%

#1937Medium

Maximum Number of Points with Cost

ArrayDynamic ProgrammingMatrix

Acceptance: 41.8%

#1938Hard

Maximum Genetic Difference Query

ArrayBit ManipulationDepth-First Search+2

Acceptance: 48.0%

#1939Easy

Users That Actively Request Confirmation Messages

Database

Acceptance: 56.4%

#1940Medium

Longest Common Subsequence Between Sorted Arrays

ArrayCountingHash Table

Acceptance: 81.3%

#1941Easy

Check if All Characters Have Equal Number of Occurrences

CountingHash TableString

Acceptance: 79.4%

#1942Medium

The Number of the Smallest Unoccupied Chair

ArrayHash TableHeap (Priority Queue)

Acceptance: 60.3%

#1943Medium

Describe the Painting

ArrayHash TablePrefix Sum+1

Acceptance: 52.7%

#1944Hard

Number of Visible People in a Queue

ArrayMonotonic StackStack

Acceptance: 73.3%

#1945Easy

Sum of Digits of String After Convert

SimulationString

Acceptance: 74.9%

#1946Medium

Largest Number After Mutating Substring

ArrayGreedyString

Acceptance: 38.5%

#1947Medium

Maximum Compatibility Score Sum

ArrayBacktrackingBit Manipulation+2

Acceptance: 65.0%

#1948Hard

Delete Duplicate Folders in System

ArrayHash FunctionHash Table+2

Acceptance: 77.7%

#1949Medium

Strong Friendship

Database

Acceptance: 54.6%

#1950Medium

Maximum of Minimum Values in All Subarrays

ArrayMonotonic StackStack

Acceptance: 48.0%

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