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
2001. Number of Pairs of Interchangeable Rectangles	Medium	53.1%	Array Counting+3	Read
2002. Maximum Product of the Length of Two Palindromic Subsequences	Medium	62.4%	Backtracking Bit Manipulation+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
2006. Count Number of Pairs With Absolute Difference K	Easy	85.4%	Array Counting+1	Read
2007. Find Original Array From Doubled Array	Medium	40.5%	Array Greedy+2	Read
2008. Maximum Earnings From Taxi	Medium	46.9%	Array Binary Search+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
2011. Final Value of Variable After Performing Operations	Easy	90.6%	Array Simulation+1	Read
2012. Sum of Beauty in the Array	Medium	51.8%	Array	Read
2013. Detect Squares	Medium	53.0%	Array Counting+2	Read
2014. Longest Subsequence Repeated k Times	Hard	71.3%	Backtracking Counting+3	Read
2015. Average Height of Buildings in Each Segment	Medium	57.9%	Array Greedy+2	Read
2016. Maximum Difference Between Increasing Elements	Easy	66.5%	Array	Read
2017. Grid Game	Medium	60.9%	Array Matrix+1	Read
2018. Check if Word Can Be Placed In Crossword	Medium	50.7%	Array Enumeration+1	Read
2019. The Score of Students Solving Math Expression	Hard	34.8%	Array Dynamic Programming+4	Read
2020. Number of Accounts That Did Not Stream	Medium	72.0%	Database	Read
2021. Brightest Position on Street	Medium	60.5%	Array Ordered Set+1	Read
2022. Convert 1D Array Into 2D Array	Easy	72.2%	Array Matrix+1	Read
2023. Number of Pairs of Strings With Concatenation Equal to Target	Medium	75.1%	Array Counting+2	Read
2024. Maximize the Confusion of an Exam	Medium	70.4%	Binary Search Prefix Sum+2	Read
2025. Maximum Number of Ways to Partition an Array	Hard	36.2%	Array Counting+3	Read
2026. Low-Quality Problems	Easy	84.3%	Database	Read
2027. Minimum Moves to Convert String	Easy	58.4%	Greedy String	Read
2028. Find Missing Observations	Medium	57.5%	Array Math+1	Read
2029. Stone Game IX	Medium	57.6%	Array Counting+3	Read
2030. Smallest K-Length Subsequence With Occurrences of a Letter	Hard	40.0%	Greedy Monotonic Stack+2	Read
2031. Count Subarrays With More Ones Than Zeros	Medium	49.7%	Array Binary Indexed Tree+5	Read
2032. Two Out of Three	Easy	77.5%	Array Bit Manipulation+1	Read
2033. Minimum Operations to Make a Uni-Value Grid	Medium	70.7%	Array Math+2	Read
2034. Stock Price Fluctuation	Medium	49.1%	Data Stream Design+3	Read
2035. Partition Array Into Two Arrays to Minimize Sum Difference	Hard	24.4%	Array Binary Search+5	Read
2036. Maximum Alternating Subarray Sum	Medium	40.0%	Array Dynamic Programming	Read
2037. Minimum Number of Moves to Seat Everyone	Easy	87.4%	Array Counting Sort+2	Read
2038. Remove Colored Pieces if Both Neighbors are the Same Color	Medium	62.8%	Game Theory Greedy+2	Read
2039. The Time When the Network Becomes Idle	Medium	56.1%	Array Breadth-First Search+1	Read
2040. Kth Smallest Product of Two Sorted Arrays	Hard	48.8%	Array Binary Search	Read
2041. Accepted Candidates From the Interviews	Medium	78.5%	Database	Read
2042. Check if Numbers Are Ascending in a Sentence	Easy	73.6%	String	Read
2043. Simple Bank System	Medium	69.7%	Array Design+2	Read
2044. Count Number of Maximum Bitwise-OR Subsets	Medium	89.5%	Array Backtracking+2	Read
2045. Second Minimum Time to Reach Destination	Hard	62.3%	Breadth-First Search Graph+1	Read
2046. Sort Linked List Already Sorted Using Absolute Values	Medium	67.1%	Linked List Sorting+1	Read
2047. Number of Valid Words in a Sentence	Easy	31.0%	String	Read
2048. Next Greater Numerically Balanced Number	Medium	63.1%	Backtracking Enumeration+1	Read
2049. Count Nodes With the Highest Score	Medium	52.6%	Array Binary Tree+2	Read
2050. Parallel Courses III	Hard	67.0%	Array Dynamic Programming+2	Read

#2001Medium

Number of Pairs of Interchangeable Rectangles

ArrayCountingHash Table+2

Acceptance: 53.1%

#2002Medium

Maximum Product of the Length of Two Palindromic Subsequences

BacktrackingBit ManipulationBitmask+2

Acceptance: 62.4%

#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%

#2006Easy

Count Number of Pairs With Absolute Difference K

ArrayCountingHash Table

Acceptance: 85.4%

#2007Medium

Find Original Array From Doubled Array

ArrayGreedyHash Table+1

Acceptance: 40.5%

#2008Medium

Maximum Earnings From Taxi

ArrayBinary SearchDynamic Programming+2

Acceptance: 46.9%

#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%

#2011Easy

Final Value of Variable After Performing Operations

ArraySimulationString

Acceptance: 90.6%

#2012Medium

Sum of Beauty in the Array

Array

Acceptance: 51.8%

#2013Medium

Detect Squares

ArrayCountingDesign+1

Acceptance: 53.0%

#2014Hard

Longest Subsequence Repeated k Times

BacktrackingCountingEnumeration+2

Acceptance: 71.3%

#2015Medium

Average Height of Buildings in Each Segment

ArrayGreedyHeap (Priority Queue)+1

Acceptance: 57.9%

#2016Easy

Maximum Difference Between Increasing Elements

Array

Acceptance: 66.5%

#2017Medium

Grid Game

ArrayMatrixPrefix Sum

Acceptance: 60.9%

#2018Medium

Check if Word Can Be Placed In Crossword

ArrayEnumerationMatrix

Acceptance: 50.7%

#2019Hard

The Score of Students Solving Math Expression

ArrayDynamic ProgrammingMath+3

Acceptance: 34.8%

#2020Medium

Number of Accounts That Did Not Stream

Database

Acceptance: 72.0%

#2021Medium

Brightest Position on Street

ArrayOrdered SetPrefix Sum

Acceptance: 60.5%

#2022Easy

Convert 1D Array Into 2D Array

ArrayMatrixSimulation

Acceptance: 72.2%

#2023Medium

Number of Pairs of Strings With Concatenation Equal to Target

ArrayCountingHash Table+1

Acceptance: 75.1%

#2024Medium

Maximize the Confusion of an Exam

Binary SearchPrefix SumSliding Window+1

Acceptance: 70.4%

#2025Hard

Maximum Number of Ways to Partition an Array

ArrayCountingEnumeration+2

Acceptance: 36.2%

#2026Easy

Low-Quality Problems

Database

Acceptance: 84.3%

#2027Easy

Minimum Moves to Convert String

GreedyString

Acceptance: 58.4%

#2028Medium

Find Missing Observations

ArrayMathSimulation

Acceptance: 57.5%

#2029Medium

Stone Game IX

ArrayCountingGame Theory+2

Acceptance: 57.6%

#2030Hard

Smallest K-Length Subsequence With Occurrences of a Letter

GreedyMonotonic StackStack+1

Acceptance: 40.0%

#2031Medium

Count Subarrays With More Ones Than Zeros

ArrayBinary Indexed TreeBinary Search+4

Acceptance: 49.7%

#2032Easy

Two Out of Three

ArrayBit ManipulationHash Table

Acceptance: 77.5%

#2033Medium

Minimum Operations to Make a Uni-Value Grid

ArrayMathMatrix+1

Acceptance: 70.7%

#2034Medium

Stock Price Fluctuation

Data StreamDesignHash Table+2

Acceptance: 49.1%

#2035Hard

Partition Array Into Two Arrays to Minimize Sum Difference

ArrayBinary SearchBit Manipulation+4

Acceptance: 24.4%

#2036Medium

Maximum Alternating Subarray Sum

ArrayDynamic Programming

Acceptance: 40.0%

#2037Easy

Minimum Number of Moves to Seat Everyone

ArrayCounting SortGreedy+1

Acceptance: 87.4%

#2038Medium

Remove Colored Pieces if Both Neighbors are the Same Color

Game TheoryGreedyMath+1

Acceptance: 62.8%

#2039Medium

The Time When the Network Becomes Idle

ArrayBreadth-First SearchGraph

Acceptance: 56.1%

#2040Hard

Kth Smallest Product of Two Sorted Arrays

ArrayBinary Search

Acceptance: 48.8%

#2041Medium

Accepted Candidates From the Interviews

Database

Acceptance: 78.5%

#2042Easy

Check if Numbers Are Ascending in a Sentence

String

Acceptance: 73.6%

#2043Medium

Simple Bank System

ArrayDesignHash Table+1

Acceptance: 69.7%

#2044Medium

Count Number of Maximum Bitwise-OR Subsets

ArrayBacktrackingBit Manipulation+1

Acceptance: 89.5%

#2045Hard

Second Minimum Time to Reach Destination

Breadth-First SearchGraphShortest Path

Acceptance: 62.3%

#2046Medium

Sort Linked List Already Sorted Using Absolute Values

Linked ListSortingTwo Pointers

Acceptance: 67.1%

#2047Easy

Number of Valid Words in a Sentence

String

Acceptance: 31.0%

#2048Medium

Next Greater Numerically Balanced Number

BacktrackingEnumerationMath

Acceptance: 63.1%

#2049Medium

Count Nodes With the Highest Score

ArrayBinary TreeDepth-First Search+1

Acceptance: 52.6%

#2050Hard

Parallel Courses III

ArrayDynamic ProgrammingGraph+1

Acceptance: 67.0%

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