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
1912. Design Movie Rental System	Hard	62.5%	Array Design+3	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
1919. Leetcodify Similar Friends	Hard	42.4%	Database	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
1928. Minimum Cost to Reach Destination in Time	Hard	42.0%	Array Dynamic Programming+1	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
1938. Maximum Genetic Difference Query	Hard	48.0%	Array Bit Manipulation+3	Read
1944. Number of Visible People in a Queue	Hard	73.3%	Array Monotonic Stack+1	Read
1948. Delete Duplicate Folders in System	Hard	77.7%	Array Hash Function+3	Read
1955. Count Number of Special Subsequences	Hard	52.8%	Array Dynamic Programming	Read
1956. Minimum Time For K Virus Variants to Spread	Hard	49.5%	Array Binary Search+3	Read
1960. Maximum Product of the Length of Two Palindromic Substrings	Hard	32.1%	Hash Function Rolling Hash+1	Read
1964. Find the Longest Valid Obstacle Course at Each Position	Hard	62.8%	Array Binary Indexed Tree+1	Read
1970. Last Day Where You Can Still Cross	Hard	68.7%	Array Binary Search+4	Read
1972. First and Last Call On the Same Day	Hard	50.7%	Database	Read
1977. Number of Ways to Separate Numbers	Hard	21.7%	Dynamic Programming String+1	Read
1982. Find Array Given Subset Sums	Hard	49.7%	Array Divide and Conquer	Read
1987. Number of Unique Good Subsequences	Hard	52.7%	Dynamic Programming String	Read
1994. The Number of Good Subsets	Hard	37.8%	Array Bit Manipulation+3	Read
1998. GCD Sort of an Array	Hard	50.7%	Array Math+3	Read
2003. Smallest Missing Genetic Value in Each Subtree	Hard	48.4%	Depth-First Search Dynamic Programming+2	Read
2004. The Number of Seniors and Juniors to Join the Company	Hard	44.0%	Database	Read
2005. Subtree Removal Game with Fibonacci Tree	Hard	54.9%	Binary Tree Dynamic Programming+3	Read
2009. Minimum Number of Operations to Make Array Continuous	Hard	52.0%	Array Binary Search+2	Read
2010. The Number of Seniors and Juniors to Join the Company II	Hard	63.2%	Database	Read
2014. Longest Subsequence Repeated k Times	Hard	71.3%	Backtracking Counting+3	Read
2019. The Score of Students Solving Math Expression	Hard	34.8%	Array Dynamic Programming+4	Read
2025. Maximum Number of Ways to Partition an Array	Hard	36.2%	Array Counting+3	Read
2030. Smallest K-Length Subsequence With Occurrences of a Letter	Hard	40.0%	Greedy Monotonic Stack+2	Read
2035. Partition Array Into Two Arrays to Minimize Sum Difference	Hard	24.4%	Array Binary Search+5	Read
2040. Kth Smallest Product of Two Sorted Arrays	Hard	48.8%	Array Binary Search	Read
2045. Second Minimum Time to Reach Destination	Hard	62.3%	Breadth-First Search Graph+1	Read
2050. Parallel Courses III	Hard	67.0%	Array Dynamic Programming+2	Read
2056. Number of Valid Move Combinations On Chessboard	Hard	48.1%	Array Backtracking+2	Read
2060. Check if an Original String Exists Given Two Encoded Strings	Hard	43.6%	Dynamic Programming String	Read
2065. Maximum Path Quality of a Graph	Hard	63.1%	Array Backtracking+1	Read
2071. Maximum Number of Tasks You Can Assign	Hard	50.1%	Array Binary Search+4	Read
2076. Process Restricted Friend Requests	Hard	61.7%	Graph Union Find	Read
2081. Sum of k-Mirror Numbers	Hard	63.7%	Enumeration Math	Read
2088. Count Fertile Pyramids in a Land	Hard	66.5%	Array Dynamic Programming+1	Read
2092. Find All People With Secret	Hard	48.4%	Breadth-First Search Depth-First Search+3	Read
2097. Valid Arrangement of Pairs	Hard	66.5%	Depth-First Search Eulerian Circuit+1	Read
2102. Sequentially Ordinal Rank Tracker	Hard	61.5%	Data Stream Design+2	Read
2106. Maximum Fruits Harvested After at Most K Steps	Hard	61.0%	Array Binary Search+2	Read
2111. Minimum Operations to Make the Array K-Increasing	Hard	40.5%	Array Binary Search	Read
2117. Abbreviating the Product of a Range	Hard	25.0%	Math	Read
2118. Build the Equation	Hard	55.9%	Database	Read

#1912Hard

Design Movie Rental System

ArrayDesignHash Table+2

Acceptance: 62.5%

#1916Hard

Count Ways to Build Rooms in an Ant Colony

CombinatoricsDynamic ProgrammingGraph+3

Acceptance: 51.8%

#1917Hard

Leetcodify Friends Recommendations

Database

Acceptance: 27.5%

#1919Hard

Leetcodify Similar Friends

Database

Acceptance: 42.4%

#1923Hard

Longest Common Subpath

ArrayBinary SearchHash Function+2

Acceptance: 30.1%

#1924Hard

Erect the Fence II

ArrayGeometryMath

Acceptance: 49.4%

#1928Hard

Minimum Cost to Reach Destination in Time

ArrayDynamic ProgrammingGraph

Acceptance: 42.0%

#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%

#1938Hard

Maximum Genetic Difference Query

ArrayBit ManipulationDepth-First Search+2

Acceptance: 48.0%

#1944Hard

Number of Visible People in a Queue

ArrayMonotonic StackStack

Acceptance: 73.3%

#1948Hard

Delete Duplicate Folders in System

ArrayHash FunctionHash Table+2

Acceptance: 77.7%

#1955Hard

Count Number of Special Subsequences

ArrayDynamic Programming

Acceptance: 52.8%

#1956Hard

Minimum Time For K Virus Variants to Spread

ArrayBinary SearchEnumeration+2

Acceptance: 49.5%

#1960Hard

Maximum Product of the Length of Two Palindromic Substrings

Hash FunctionRolling HashString

Acceptance: 32.1%

#1964Hard

Find the Longest Valid Obstacle Course at Each Position

ArrayBinary Indexed TreeBinary Search

Acceptance: 62.8%

#1970Hard

Last Day Where You Can Still Cross

ArrayBinary SearchBreadth-First Search+3

Acceptance: 68.7%

#1972Hard

First and Last Call On the Same Day

Database

Acceptance: 50.7%

#1977Hard

Number of Ways to Separate Numbers

Dynamic ProgrammingStringSuffix Array

Acceptance: 21.7%

#1982Hard

Find Array Given Subset Sums

ArrayDivide and Conquer

Acceptance: 49.7%

#1987Hard

Number of Unique Good Subsequences

Dynamic ProgrammingString

Acceptance: 52.7%

#1994Hard

The Number of Good Subsets

ArrayBit ManipulationBitmask+2

Acceptance: 37.8%

#1998Hard

GCD Sort of an Array

ArrayMathNumber Theory+2

Acceptance: 50.7%

#2003Hard

Smallest Missing Genetic Value in Each Subtree

Depth-First SearchDynamic ProgrammingTree+1

Acceptance: 48.4%

#2004Hard

The Number of Seniors and Juniors to Join the Company

Database

Acceptance: 44.0%

#2005Hard

Subtree Removal Game with Fibonacci Tree

Binary TreeDynamic ProgrammingGame Theory+2

Acceptance: 54.9%

#2009Hard

Minimum Number of Operations to Make Array Continuous

ArrayBinary SearchHash Table+1

Acceptance: 52.0%

#2010Hard

The Number of Seniors and Juniors to Join the Company II

Database

Acceptance: 63.2%

#2014Hard

Longest Subsequence Repeated k Times

BacktrackingCountingEnumeration+2

Acceptance: 71.3%

#2019Hard

The Score of Students Solving Math Expression

ArrayDynamic ProgrammingMath+3

Acceptance: 34.8%

#2025Hard

Maximum Number of Ways to Partition an Array

ArrayCountingEnumeration+2

Acceptance: 36.2%

#2030Hard

Smallest K-Length Subsequence With Occurrences of a Letter

GreedyMonotonic StackStack+1

Acceptance: 40.0%

#2035Hard

Partition Array Into Two Arrays to Minimize Sum Difference

ArrayBinary SearchBit Manipulation+4

Acceptance: 24.4%

#2040Hard

Kth Smallest Product of Two Sorted Arrays

ArrayBinary Search

Acceptance: 48.8%

#2045Hard

Second Minimum Time to Reach Destination

Breadth-First SearchGraphShortest Path

Acceptance: 62.3%

#2050Hard

Parallel Courses III

ArrayDynamic ProgrammingGraph+1

Acceptance: 67.0%

#2056Hard

Number of Valid Move Combinations On Chessboard

ArrayBacktrackingSimulation+1

Acceptance: 48.1%

#2060Hard

Check if an Original String Exists Given Two Encoded Strings

Dynamic ProgrammingString

Acceptance: 43.6%

#2065Hard

Maximum Path Quality of a Graph

ArrayBacktrackingGraph

Acceptance: 63.1%

#2071Hard

Maximum Number of Tasks You Can Assign

ArrayBinary SearchGreedy+3

Acceptance: 50.1%

#2076Hard

Process Restricted Friend Requests

GraphUnion Find

Acceptance: 61.7%

#2081Hard

Sum of k-Mirror Numbers

EnumerationMath

Acceptance: 63.7%

#2088Hard

Count Fertile Pyramids in a Land

ArrayDynamic ProgrammingMatrix

Acceptance: 66.5%

#2092Hard

Find All People With Secret

Breadth-First SearchDepth-First SearchGraph+2

Acceptance: 48.4%

#2097Hard

Valid Arrangement of Pairs

Depth-First SearchEulerian CircuitGraph

Acceptance: 66.5%

#2102Hard

Sequentially Ordinal Rank Tracker

Data StreamDesignHeap (Priority Queue)+1

Acceptance: 61.5%

#2106Hard

Maximum Fruits Harvested After at Most K Steps

ArrayBinary SearchPrefix Sum+1

Acceptance: 61.0%

#2111Hard

Minimum Operations to Make the Array K-Increasing

ArrayBinary Search

Acceptance: 40.5%

#2117Hard

Abbreviating the Product of a Range

Math

Acceptance: 25.0%

#2118Hard

Build the Equation

Database

Acceptance: 55.9%

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