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
607. Sales Person	Easy	65.7%	Database	Read
610. Triangle Judgement	Easy	72.9%	Database	Read
613. Shortest Distance in a Line	Easy	80.0%	Database	Read
617. Merge Two Binary Trees	Easy	79.2%	Binary Tree Breadth-First Search+2	Read
619. Biggest Single Number	Easy	67.3%	Database	Read
620. Not Boring Movies	Easy	74.5%	Database	Read
627. Swap Salary	Easy	83.6%	Database	Read
628. Maximum Product of Three Numbers	Easy	48.0%	Array Math+1	Read
637. Average of Levels in Binary Tree	Easy	74.8%	Binary Tree Breadth-First Search+2	Read
643. Maximum Average Subarray I	Easy	49.2%	Array Sliding Window	Read
645. Set Mismatch	Easy	43.4%	Array Bit Manipulation+2	Read
653. Two Sum IV - Input is a BST	Easy	63.7%	Binary Search Tree Binary Tree+5	Read
657. Robot Return to Origin	Easy	78.0%	Simulation String	Read
661. Image Smoother	Easy	69.8%	Array Matrix	Read
671. Second Minimum Node In a Binary Tree	Easy	46.0%	Binary Tree Depth-First Search+1	Read
674. Longest Continuous Increasing Subsequence	Easy	51.9%	Array	Read
680. Valid Palindrome II	Easy	44.7%	Greedy String+1	Read
682. Baseball Game	Easy	80.8%	Array Simulation+1	Read
693. Binary Number with Alternating Bits	Easy	69.8%	Bit Manipulation	Read
696. Count Binary Substrings	Easy	70.3%	String Two Pointers	Read
697. Degree of an Array	Easy	58.2%	Array Hash Table	Read
700. Search in a Binary Search Tree	Easy	83.1%	Binary Search Tree Binary Tree+1	Read
703. Kth Largest Element in a Stream	Easy	61.4%	Binary Search Tree Binary Tree+4	Read
704. Binary Search	Easy	61.2%	Array Binary Search	Read
705. Design HashSet	Easy	67.9%	Array Design+3	Read
706. Design HashMap	Easy	66.5%	Array Design+3	Read
709. To Lower Case	Easy	84.8%	String	Read
717. 1-bit and 2-bit Characters	Easy	49.5%	Array	Read
724. Find Pivot Index	Easy	63.6%	Array Prefix Sum	Read
728. Self Dividing Numbers	Easy	81.3%	Math	Read
733. Flood Fill	Easy	68.6%	Array Breadth-First Search+2	Read
734. Sentence Similarity	Easy	44.5%	Array Hash Table+1	Read
744. Find Smallest Letter Greater Than Target	Easy	59.6%	Array Binary Search	Read
746. Min Cost Climbing Stairs	Easy	68.7%	Array Dynamic Programming	Read
747. Largest Number At Least Twice of Others	Easy	52.8%	Array Sorting	Read
748. Shortest Completing Word	Easy	63.5%	Array Hash Table+1	Read
760. Find Anagram Mappings	Easy	83.8%	Array Hash Table	Read
762. Prime Number of Set Bits in Binary Representation	Easy	78.7%	Bit Manipulation Math	Read
766. Toeplitz Matrix	Easy	69.8%	Array Matrix	Read
771. Jewels and Stones	Easy	89.5%	Hash Table String	Read
783. Minimum Distance Between BST Nodes	Easy	61.8%	Binary Search Tree Binary Tree+3	Read
796. Rotate String	Easy	66.6%	String String Matching	Read
800. Similar RGB Color	Easy	68.6%	Enumeration Math+1	Read
804. Unique Morse Code Words	Easy	83.6%	Array Hash Table+1	Read
806. Number of Lines To Write String	Easy	72.9%	Array String	Read
812. Largest Triangle Area	Easy	72.1%	Array Geometry+1	Read
819. Most Common Word	Easy	45.0%	Array Counting+2	Read
821. Shortest Distance to a Character	Easy	72.7%	Array String+1	Read
824. Goat Latin	Easy	69.9%	String	Read
830. Positions of Large Groups	Easy	54.4%	String	Read

#607Easy

Sales Person

Database

Acceptance: 65.7%

#610Easy

Triangle Judgement

Database

Acceptance: 72.9%

#613Easy

Shortest Distance in a Line

Database

Acceptance: 80.0%

#617Easy

Merge Two Binary Trees

Binary TreeBreadth-First SearchDepth-First Search+1

Acceptance: 79.2%

#619Easy

Biggest Single Number

Database

Acceptance: 67.3%

#620Easy

Not Boring Movies

Database

Acceptance: 74.5%

#627Easy

Swap Salary

Database

Acceptance: 83.6%

#628Easy

Maximum Product of Three Numbers

ArrayMathSorting

Acceptance: 48.0%

#637Easy

Average of Levels in Binary Tree

Binary TreeBreadth-First SearchDepth-First Search+1

Acceptance: 74.8%

#643Easy

Maximum Average Subarray I

ArraySliding Window

Acceptance: 49.2%

#645Easy

Set Mismatch

ArrayBit ManipulationHash Table+1

Acceptance: 43.4%

#653Easy

Two Sum IV - Input is a BST

Binary Search TreeBinary TreeBreadth-First Search+4

Acceptance: 63.7%

#657Easy

Robot Return to Origin

SimulationString

Acceptance: 78.0%

#661Easy

Image Smoother

ArrayMatrix

Acceptance: 69.8%

#671Easy

Second Minimum Node In a Binary Tree

Binary TreeDepth-First SearchTree

Acceptance: 46.0%

#674Easy

Longest Continuous Increasing Subsequence

Array

Acceptance: 51.9%

#680Easy

Valid Palindrome II

GreedyStringTwo Pointers

Acceptance: 44.7%

#682Easy

Baseball Game

ArraySimulationStack

Acceptance: 80.8%

#693Easy

Binary Number with Alternating Bits

Bit Manipulation

Acceptance: 69.8%

#696Easy

Count Binary Substrings

StringTwo Pointers

Acceptance: 70.3%

#697Easy

Degree of an Array

ArrayHash Table

Acceptance: 58.2%

#700Easy

Search in a Binary Search Tree

Binary Search TreeBinary TreeTree

Acceptance: 83.1%

#703Easy

Kth Largest Element in a Stream

Binary Search TreeBinary TreeData Stream+3

Acceptance: 61.4%

#704Easy

Binary Search

ArrayBinary Search

Acceptance: 61.2%

#705Easy

Design HashSet

ArrayDesignHash Function+2

Acceptance: 67.9%

#706Easy

Design HashMap

ArrayDesignHash Function+2

Acceptance: 66.5%

#709Easy

To Lower Case

String

Acceptance: 84.8%

#717Easy

1-bit and 2-bit Characters

Array

Acceptance: 49.5%

#724Easy

Find Pivot Index

ArrayPrefix Sum

Acceptance: 63.6%

#728Easy

Self Dividing Numbers

Math

Acceptance: 81.3%

#733Easy

Flood Fill

ArrayBreadth-First SearchDepth-First Search+1

Acceptance: 68.6%

#734Easy

Sentence Similarity

ArrayHash TableString

Acceptance: 44.5%

#744Easy

Find Smallest Letter Greater Than Target

ArrayBinary Search

Acceptance: 59.6%

#746Easy

Min Cost Climbing Stairs

ArrayDynamic Programming

Acceptance: 68.7%

#747Easy

Largest Number At Least Twice of Others

ArraySorting

Acceptance: 52.8%

#748Easy

Shortest Completing Word

ArrayHash TableString

Acceptance: 63.5%

#760Easy

Find Anagram Mappings

ArrayHash Table

Acceptance: 83.8%

#762Easy

Prime Number of Set Bits in Binary Representation

Bit ManipulationMath

Acceptance: 78.7%

#766Easy

Toeplitz Matrix

ArrayMatrix

Acceptance: 69.8%

#771Easy

Jewels and Stones

Hash TableString

Acceptance: 89.5%

#783Easy

Minimum Distance Between BST Nodes

Binary Search TreeBinary TreeBreadth-First Search+2

Acceptance: 61.8%

#796Easy

Rotate String

StringString Matching

Acceptance: 66.6%

#800Easy

Similar RGB Color

EnumerationMathString

Acceptance: 68.6%

#804Easy

Unique Morse Code Words

ArrayHash TableString

Acceptance: 83.6%

#806Easy

Number of Lines To Write String

ArrayString

Acceptance: 72.9%

#812Easy

Largest Triangle Area

ArrayGeometryMath

Acceptance: 72.1%

#819Easy

Most Common Word

ArrayCountingHash Table+1

Acceptance: 45.0%

#821Easy

Shortest Distance to a Character

ArrayStringTwo Pointers

Acceptance: 72.7%

#824Easy

Goat Latin

String

Acceptance: 69.9%

#830Easy

Positions of Large Groups

String

Acceptance: 54.4%

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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