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
2139. Minimum Moves to Reach Target Score	Medium	52.3%	Greedy Math	Read
2140. Solving Questions With Brainpower	Medium	60.2%	Array Dynamic Programming	Read
2142. The Number of Passengers in Each Bus I	Medium	48.8%	Database	Read
2145. Count the Hidden Sequences	Medium	56.7%	Array Prefix Sum	Read
2146. K Highest Ranked Items Within a Price Range	Medium	47.1%	Array Breadth-First Search+3	Read
2149. Rearrange Array Elements by Sign	Medium	84.7%	Array Simulation+1	Read
2150. Find All Lonely Numbers in the Array	Medium	63.4%	Array Counting+1	Read
2152. Minimum Number of Lines to Cover Points	Medium	43.9%	Array Backtracking+6	Read
2155. All Divisions With the Highest Score of a Binary Array	Medium	65.5%	Array	Read
2159. Order Two Columns Independently	Medium	60.5%	Database	Read
2161. Partition Array According to Given Pivot	Medium	90.8%	Array Simulation+1	Read
2162. Minimum Cost to Set Cooking Time	Medium	45.0%	Enumeration Math	Read
2165. Smallest Value of the Rearranged Number	Medium	53.5%	Math Sorting	Read
2166. Design Bitset	Medium	32.7%	Array Design+2	Read
2168. Unique Substrings With Equal Digit Frequency	Medium	64.6%	Counting Hash Function+3	Read
2170. Minimum Operations to Make the Array Alternating	Medium	35.7%	Array Counting+2	Read
2171. Removing Minimum Number of Magic Beans	Medium	44.5%	Array Enumeration+3	Read
2174. Remove All Ones With Row and Column Flips II	Medium	67.2%	Array Bit Manipulation+2	Read
2175. The Change in Global Rankings	Medium	60.1%	Database	Read
2177. Find Three Consecutive Integers That Sum to a Given Number	Medium	65.3%	Math Simulation	Read
2178. Maximum Split of Positive Even Integers	Medium	59.9%	Backtracking Greedy+1	Read
2181. Merge Nodes in Between Zeros	Medium	89.8%	Linked List Simulation	Read
2182. Construct String With Repeat Limit	Medium	70.9%	Counting Greedy+3	Read
2184. Number of Ways to Build Sturdy Brick Wall	Medium	49.2%	Array Bit Manipulation+2	Read
2186. Minimum Number of Steps to Make Two Strings Anagram II	Medium	72.7%	Counting Hash Table+1	Read
2187. Minimum Time to Complete Trips	Medium	39.6%	Array Binary Search	Read
2189. Number of Ways to Build House of Cards	Medium	62.7%	Dynamic Programming Math	Read
2191. Sort the Jumbled Numbers	Medium	60.1%	Array Sorting	Read
2192. All Ancestors of a Node in a Directed Acyclic Graph	Medium	62.1%	Breadth-First Search Depth-First Search+2	Read
2195. Append K Integers With Minimal Sum	Medium	26.9%	Array Greedy+2	Read
2196. Create Binary Tree From Descriptions	Medium	83.9%	Array Binary Tree+2	Read
2198. Number of Single Divisor Triplets	Medium	53.1%	Math	Read
2201. Count Artifacts That Can Be Extracted	Medium	57.1%	Array Hash Table+1	Read
2202. Maximize the Topmost Element After K Moves	Medium	24.0%	Array Greedy	Read
2207. Maximize Number of Subsequences in a String	Medium	36.0%	Greedy Prefix Sum+1	Read
2208. Minimum Operations to Halve Array Sum	Medium	50.1%	Array Greedy+1	Read
2211. Count Collisions on a Road	Medium	58.1%	Simulation Stack+1	Read
2212. Maximum Points in an Archery Competition	Medium	52.2%	Array Backtracking+2	Read
2214. Minimum Health to Beat Game	Medium	58.9%	Array Greedy	Read
2216. Minimum Deletions to Make Array Beautiful	Medium	50.5%	Array Greedy+1	Read
2217. Find Palindrome With Fixed Length	Medium	38.0%	Array Math	Read
2219. Maximum Sum Score of Array	Medium	62.6%	Array Prefix Sum	Read
2221. Find Triangular Sum of an Array	Medium	82.0%	Array Combinatorics+2	Read
2222. Number of Ways to Select Buildings	Medium	50.8%	Dynamic Programming Prefix Sum+1	Read
2225. Find Players With Zero or One Losses	Medium	72.4%	Array Counting+2	Read
2226. Maximum Candies Allocated to K Children	Medium	49.9%	Array Binary Search	Read
2228. Users With Two Purchases Within Seven Days	Medium	45.2%	Database	Read
2232. Minimize Result by Adding Parentheses to Expression	Medium	68.4%	Enumeration String	Read
2233. Maximum Product After K Increments	Medium	44.0%	Array Greedy+1	Read
2237. Count Positions on Street With Required Brightness	Medium	62.4%	Array Prefix Sum	Read

#2139Medium

Minimum Moves to Reach Target Score

GreedyMath

Acceptance: 52.3%

#2140Medium

Solving Questions With Brainpower

ArrayDynamic Programming

Acceptance: 60.2%

#2142Medium

The Number of Passengers in Each Bus I

Database

Acceptance: 48.8%

#2145Medium

Count the Hidden Sequences

ArrayPrefix Sum

Acceptance: 56.7%

#2146Medium

K Highest Ranked Items Within a Price Range

ArrayBreadth-First SearchHeap (Priority Queue)+2

Acceptance: 47.1%

#2149Medium

Rearrange Array Elements by Sign

ArraySimulationTwo Pointers

Acceptance: 84.7%

#2150Medium

Find All Lonely Numbers in the Array

ArrayCountingHash Table

Acceptance: 63.4%

#2152Medium

Minimum Number of Lines to Cover Points

ArrayBacktrackingBit Manipulation+5

Acceptance: 43.9%

#2155Medium

All Divisions With the Highest Score of a Binary Array

Array

Acceptance: 65.5%

#2159Medium

Order Two Columns Independently

Database

Acceptance: 60.5%

#2161Medium

Partition Array According to Given Pivot

ArraySimulationTwo Pointers

Acceptance: 90.8%

#2162Medium

Minimum Cost to Set Cooking Time

EnumerationMath

Acceptance: 45.0%

#2165Medium

Smallest Value of the Rearranged Number

MathSorting

Acceptance: 53.5%

#2166Medium

Design Bitset

ArrayDesignHash Table+1

Acceptance: 32.7%

#2168Medium

Unique Substrings With Equal Digit Frequency

CountingHash FunctionHash Table+2

Acceptance: 64.6%

#2170Medium

Minimum Operations to Make the Array Alternating

ArrayCountingGreedy+1

Acceptance: 35.7%

#2171Medium

Removing Minimum Number of Magic Beans

ArrayEnumerationGreedy+2

Acceptance: 44.5%

#2174Medium

Remove All Ones With Row and Column Flips II

ArrayBit ManipulationBreadth-First Search+1

Acceptance: 67.2%

#2175Medium

The Change in Global Rankings

Database

Acceptance: 60.1%

#2177Medium

Find Three Consecutive Integers That Sum to a Given Number

MathSimulation

Acceptance: 65.3%

#2178Medium

Maximum Split of Positive Even Integers

BacktrackingGreedyMath

Acceptance: 59.9%

#2181Medium

Merge Nodes in Between Zeros

Linked ListSimulation

Acceptance: 89.8%

#2182Medium

Construct String With Repeat Limit

CountingGreedyHash Table+2

Acceptance: 70.9%

#2184Medium

Number of Ways to Build Sturdy Brick Wall

ArrayBit ManipulationBitmask+1

Acceptance: 49.2%

#2186Medium

Minimum Number of Steps to Make Two Strings Anagram II

CountingHash TableString

Acceptance: 72.7%

#2187Medium

Minimum Time to Complete Trips

ArrayBinary Search

Acceptance: 39.6%

#2189Medium

Number of Ways to Build House of Cards

Dynamic ProgrammingMath

Acceptance: 62.7%

#2191Medium

Sort the Jumbled Numbers

ArraySorting

Acceptance: 60.1%

#2192Medium

All Ancestors of a Node in a Directed Acyclic Graph

Breadth-First SearchDepth-First SearchGraph+1

Acceptance: 62.1%

#2195Medium

Append K Integers With Minimal Sum

ArrayGreedyMath+1

Acceptance: 26.9%

#2196Medium

Create Binary Tree From Descriptions

ArrayBinary TreeHash Table+1

Acceptance: 83.9%

#2198Medium

Number of Single Divisor Triplets

Math

Acceptance: 53.1%

#2201Medium

Count Artifacts That Can Be Extracted

ArrayHash TableSimulation

Acceptance: 57.1%

#2202Medium

Maximize the Topmost Element After K Moves

ArrayGreedy

Acceptance: 24.0%

#2207Medium

Maximize Number of Subsequences in a String

GreedyPrefix SumString

Acceptance: 36.0%

#2208Medium

Minimum Operations to Halve Array Sum

ArrayGreedyHeap (Priority Queue)

Acceptance: 50.1%

#2211Medium

Count Collisions on a Road

SimulationStackString

Acceptance: 58.1%

#2212Medium

Maximum Points in an Archery Competition

ArrayBacktrackingBit Manipulation+1

Acceptance: 52.2%

#2214Medium

Minimum Health to Beat Game

ArrayGreedy

Acceptance: 58.9%

#2216Medium

Minimum Deletions to Make Array Beautiful

ArrayGreedyStack

Acceptance: 50.5%

#2217Medium

Find Palindrome With Fixed Length

ArrayMath

Acceptance: 38.0%

#2219Medium

Maximum Sum Score of Array

ArrayPrefix Sum

Acceptance: 62.6%

#2221Medium

Find Triangular Sum of an Array

ArrayCombinatoricsMath+1

Acceptance: 82.0%

#2222Medium

Number of Ways to Select Buildings

Dynamic ProgrammingPrefix SumString

Acceptance: 50.8%

#2225Medium

Find Players With Zero or One Losses

ArrayCountingHash Table+1

Acceptance: 72.4%

#2226Medium

Maximum Candies Allocated to K Children

ArrayBinary Search

Acceptance: 49.9%

#2228Medium

Users With Two Purchases Within Seven Days

Database

Acceptance: 45.2%

#2232Medium

Minimize Result by Adding Parentheses to Expression

EnumerationString

Acceptance: 68.4%

#2233Medium

Maximum Product After K Increments

ArrayGreedyHeap (Priority Queue)

Acceptance: 44.0%

#2237Medium

Count Positions on Street With Required Brightness

ArrayPrefix Sum

Acceptance: 62.4%

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Master DSA with Step-by-Step Solutions

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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