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
4000. Largest Integer With Given Digit Sum	Easy	61.0%	Greedy Math	Read
4006. Count Valid Prefixes	Easy	78.0%	Counting String	Read
4010. Maximize Pair Strength Using GCD	Easy	48.6%	Array Enumeration+2	Read
4020. Elevator Requests I	Easy	84.1%	Array Simulation	Read
4024. Nearest Available Drone	Easy	66.8%	Array Enumeration	Read
4030. Elevator Requests IV	Easy	60.0%		Read
4038. Count Integers Appearing in a Single Block	Easy	44.4%	Array Counting+1	Read
4043. Count Rotations With Exactly K Equal Adjacent Pairs	Easy	71.7%	Enumeration Sliding Window+1	Read
4048. Count Values With Equally Spaced Occurrences I	Easy	74.7%	Array Hash Table	Read
4052. Cyclically Shift Rows and Columns	Easy	75.9%	Array Matrix+1	Read
4056. Number of Intersecting Interval Pairs I	Easy	61.2%		Read

#4000Easy

Largest Integer With Given Digit Sum

GreedyMath

Acceptance: 61.0%

#4006Easy

Count Valid Prefixes

CountingString

Acceptance: 78.0%

#4010Easy

Maximize Pair Strength Using GCD

ArrayEnumerationMath+1

Acceptance: 48.6%

#4020Easy

Elevator Requests I

ArraySimulation

Acceptance: 84.1%

#4024Easy

Nearest Available Drone

ArrayEnumeration

Acceptance: 66.8%

#4030Easy

Elevator Requests IV

Acceptance: 60.0%

#4038Easy

Count Integers Appearing in a Single Block

ArrayCountingHash Table

Acceptance: 44.4%

#4043Easy

Count Rotations With Exactly K Equal Adjacent Pairs

EnumerationSliding WindowString

Acceptance: 71.7%

#4048Easy

Count Values With Equally Spaced Occurrences I

ArrayHash Table

Acceptance: 74.7%

#4052Easy

Cyclically Shift Rows and Columns

ArrayMatrixSimulation

Acceptance: 75.9%

#4056Easy

Number of Intersecting Interval Pairs I

Acceptance: 61.2%

1 2 318 19 20

Page 20 of 20

Master DSA with Step-by-Step Solutions

Each solution article on FleetCode breaks down the problem into multiple approaches, from brute force to optimal, with detailed explanations and code in Python, Java, C++ and more. Understanding why an approach works - not just copying code - is what separates candidates who clear interviews from those who don't.

How to Use These Solutions

Try the problem first: Spend at least 20 minutes before reading the solution
Read all approaches: Start from brute force to understand the problem fully, then study the optimized solution
Understand the complexity: Pay attention to time and space analysis for each approach
Code it yourself: After understanding the approach, close the solution and implement from memory
Revisit after a week: Spaced repetition helps retain problem-solving patterns