Solutions & Explanations

Browse 4,029+ detailed solutions with multiple approaches, code in Python, Java, C++ and more.

4,029 Solutions961 Easy2102 Medium966 Hard

All4029 Easy961 Medium2102 Hard966

Title	Difficulty	Acceptance	Topics	Solution
151. Reverse Words in a String	Medium	57.8%	String Two Pointers	Read
152. Maximum Product Subarray	Medium	36.7%	Array Dynamic Programming	Read
153. Find Minimum in Rotated Sorted Array	Medium	55.3%	Array Binary Search	Read
154. Find Minimum in Rotated Sorted Array II	Hard	46.6%	Array Binary Search	Read
155. Min Stack	Medium	58.5%	Design Stack	Read
156. Binary Tree Upside Down	Medium	65.4%	Binary Tree Depth-First Search+1	Read
157. Read N Characters Given Read4	Easy	42.5%	Array Interactive+1	Read
158. Read N Characters Given read4 II - Call Multiple Times	Hard	43.2%	Array Interactive+1	Read
159. Longest Substring with At Most Two Distinct Characters	Medium	57.0%	Hash Table Sliding Window+1	Read
160. Intersection of Two Linked Lists	Easy	64.6%	Hash Table Linked List+1	Read
161. One Edit Distance	Medium	34.4%	String Two Pointers	Read
162. Find Peak Element	Medium	46.8%	Array Binary Search	Read
163. Missing Ranges	Easy	35.5%	Array	Read
164. Maximum Gap	Medium	52.8%	Array Bucket Sort+2	Read
165. Compare Version Numbers	Medium	46.8%	String Two Pointers	Read
166. Fraction to Recurring Decimal	Medium	31.3%	Hash Table Math+1	Read
167. Two Sum II - Input Array Is Sorted	Medium	65.5%	Array Binary Search+1	Read
168. Excel Sheet Column Title	Easy	47.3%	Math String	Read
169. Majority Element	Easy	66.2%	Array Counting+3	Read
170. Two Sum III - Data structure design	Easy	39.1%	Array Data Stream+3	Read
171. Excel Sheet Column Number	Easy	68.0%	Math String	Read
172. Factorial Trailing Zeroes	Medium	46.9%	Math	Read
173. Binary Search Tree Iterator	Medium	76.9%	Binary Search Tree Binary Tree+4	Read
174. Dungeon Game	Hard	42.2%	Array Dynamic Programming+1	Read
175. Combine Two Tables	Easy	77.1%	Database	Read
176. Second Highest Salary	Medium	42.2%	Database	Read
177. Nth Highest Salary	Medium	38.0%	Database	Read
178. Rank Scores	Medium	63.9%	Database	Read
179. Largest Number	Medium	43.3%	Array Greedy+2	Read
180. Consecutive Numbers	Medium	44.6%	Database	Read
181. Employees Earning More Than Their Managers	Easy	70.6%	Database	Read
182. Duplicate Emails	Easy	71.8%	Database	Read
183. Customers Who Never Order	Easy	69.9%	Database	Read
184. Department Highest Salary	Medium	53.2%	Database	Read
185. Department Top Three Salaries	Hard	55.8%	Database	Read
186. Reverse Words in a String II	Medium	56.6%	String Two Pointers	Read
187. Repeated DNA Sequences	Medium	53.7%	Bit Manipulation Hash Function+4	Read
188. Best Time to Buy and Sell Stock IV	Hard	50.9%	Array Dynamic Programming	Read
189. Rotate Array	Medium	45.3%	Array Math+1	Read
190. Reverse Bits	Easy	69.2%	Bit Manipulation Divide and Conquer	Read
191. Number of 1 Bits	Easy	77.1%	Bit Manipulation Divide and Conquer	Read
192. Word Frequency	Medium	26.3%	Shell	Read
193. Valid Phone Numbers	Easy	26.6%	Shell	Read
194. Transpose File	Medium	27.1%	Shell	Read
195. Tenth Line	Easy	33.8%	Shell	Read
196. Delete Duplicate Emails	Easy	63.4%	Database	Read
197. Rising Temperature	Easy	49.3%	Database	Read
198. House Robber	Medium	53.6%	Array Dynamic Programming	Read
199. Binary Tree Right Side View	Medium	70.9%	Binary Tree Breadth-First Search+2	Read
200. Number of Islands	Medium	65.2%	Array Breadth-First Search+3	Read

Reverse Words in a String

StringTwo Pointers

Acceptance: 57.8%

Maximum Product Subarray

ArrayDynamic Programming

Acceptance: 36.7%

Find Minimum in Rotated Sorted Array

ArrayBinary Search

Acceptance: 55.3%

Find Minimum in Rotated Sorted Array II

ArrayBinary Search

Acceptance: 46.6%

Min Stack

Acceptance: 58.5%

Binary Tree Upside Down

Binary TreeDepth-First SearchTree

Acceptance: 65.4%

Read N Characters Given Read4

ArrayInteractiveSimulation

Acceptance: 42.5%

Read N Characters Given read4 II - Call Multiple Times

ArrayInteractiveSimulation

Acceptance: 43.2%

Longest Substring with At Most Two Distinct Characters

Hash TableSliding WindowString

Acceptance: 57.0%

Intersection of Two Linked Lists

Hash TableLinked ListTwo Pointers

Acceptance: 64.6%

One Edit Distance

StringTwo Pointers

Acceptance: 34.4%

Find Peak Element

ArrayBinary Search

Acceptance: 46.8%

Missing Ranges

Acceptance: 35.5%

Maximum Gap

ArrayBucket SortRadix Sort+1

Acceptance: 52.8%

Compare Version Numbers

StringTwo Pointers

Acceptance: 46.8%

Fraction to Recurring Decimal

Hash TableMathString

Acceptance: 31.3%

Two Sum II - Input Array Is Sorted

ArrayBinary SearchTwo Pointers

Acceptance: 65.5%

Excel Sheet Column Title

Acceptance: 47.3%

Majority Element

ArrayCountingDivide and Conquer+2

Acceptance: 66.2%

Two Sum III - Data structure design

ArrayData StreamDesign+2

Acceptance: 39.1%

Excel Sheet Column Number

Acceptance: 68.0%

Factorial Trailing Zeroes

Acceptance: 46.9%

Binary Search Tree Iterator

Binary Search TreeBinary TreeDesign+3

Acceptance: 76.9%

Dungeon Game

ArrayDynamic ProgrammingMatrix

Acceptance: 42.2%

Combine Two Tables

Acceptance: 77.1%

Second Highest Salary

Acceptance: 42.2%

Nth Highest Salary

Acceptance: 38.0%

Rank Scores

Acceptance: 63.9%

Largest Number

ArrayGreedySorting+1

Acceptance: 43.3%

Consecutive Numbers

Acceptance: 44.6%

Employees Earning More Than Their Managers

Acceptance: 70.6%

Duplicate Emails

Acceptance: 71.8%

Customers Who Never Order

Acceptance: 69.9%

Department Highest Salary

Acceptance: 53.2%

Department Top Three Salaries

Acceptance: 55.8%

Reverse Words in a String II

StringTwo Pointers

Acceptance: 56.6%

Repeated DNA Sequences

Bit ManipulationHash FunctionHash Table+3

Acceptance: 53.7%

Best Time to Buy and Sell Stock IV

ArrayDynamic Programming

Acceptance: 50.9%

Rotate Array

ArrayMathTwo Pointers

Acceptance: 45.3%

Reverse Bits

Bit ManipulationDivide and Conquer

Acceptance: 69.2%

Number of 1 Bits

Bit ManipulationDivide and Conquer

Acceptance: 77.1%

Word Frequency

Acceptance: 26.3%

Valid Phone Numbers

Acceptance: 26.6%

Transpose File

Acceptance: 27.1%

Tenth Line

Acceptance: 33.8%

Delete Duplicate Emails

Acceptance: 63.4%

Rising Temperature

Acceptance: 49.3%

House Robber

ArrayDynamic Programming

Acceptance: 53.6%

Binary Tree Right Side View

Binary TreeBreadth-First SearchDepth-First Search+1

Acceptance: 70.9%

Number of Islands

ArrayBreadth-First SearchDepth-First Search+2

Acceptance: 65.2%

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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