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
3051. Find Candidates for Data Scientist Position	Easy	74.7%	Database	Read
3052. Maximize Items	Hard	72.0%	Database	Read
3053. Classifying Triangles by Lengths	Easy	50.3%	Database	Read
3054. Binary Tree Nodes	Medium	79.8%	Database	Read
3055. Top Percentile Fraud	Medium	58.1%	Database	Read
3056. Snaps Analysis	Medium	58.0%	Database	Read
3057. Employees Project Allocation	Hard	68.4%	Database	Read
3058. Friends With No Mutual Friends	Medium	49.4%	Database	Read
3059. Find All Unique Email Domains	Easy	69.0%	Database	Read
3060. User Activities within Time Bounds	Hard	40.6%	Database	Read
3061. Calculate Trapping Rain Water	Hard	81.1%	Database	Read
3062. Winner of the Linked List Game	Easy	77.6%	Linked List	Read
3063. Linked List Frequency	Easy	85.8%	Counting Hash Table+1	Read
3064. Guess the Number Using Bitwise Questions I	Medium	89.0%	Bit Manipulation Interactive	Read
3065. Minimum Operations to Exceed Threshold Value I	Easy	86.7%	Array	Read
3066. Minimum Operations to Exceed Threshold Value II	Medium	45.8%	Array Heap (Priority Queue)+1	Read
3067. Count Pairs of Connectable Servers in a Weighted Tree Network	Medium	55.6%	Array Depth-First Search+1	Read
3068. Find the Maximum Sum of Node Values	Hard	69.5%	Array Bit Manipulation+4	Read
3069. Distribute Elements Into Two Arrays I	Easy	83.4%	Array Simulation	Read
3070. Count Submatrices with Top-Left Element and Sum Less Than k	Medium	74.8%	Array Matrix+1	Read
3071. Minimum Operations to Write the Letter Y on a Grid	Medium	63.9%	Array Counting+2	Read
3072. Distribute Elements Into Two Arrays II	Hard	32.1%	Array Binary Indexed Tree+2	Read
3073. Maximum Increasing Triplet Value	Medium	35.7%	Array Ordered Set	Read
3074. Apple Redistribution into Boxes	Easy	78.5%	Array Greedy+1	Read
3075. Maximize Happiness of Selected Children	Medium	58.7%	Array Greedy+1	Read
3076. Shortest Uncommon Substring in an Array	Medium	50.8%	Array Hash Table+2	Read
3077. Maximum Strength of K Disjoint Subarrays	Hard	28.2%	Array Dynamic Programming+1	Read
3078. Match Alphanumerical Pattern in Matrix I	Medium	64.6%	Array Hash Table+2	Read
3079. Find the Sum of Encrypted Integers	Easy	74.7%	Array Math	Read
3080. Mark Elements on Array by Performing Queries	Medium	49.1%	Array Hash Table+3	Read
3081. Replace Question Marks in String to Minimize Its Value	Medium	29.0%	Counting Greedy+4	Read
3082. Find the Sum of the Power of All Subsequences	Hard	38.1%	Array Dynamic Programming	Read
3083. Existence of a Substring in a String and Its Reverse	Easy	66.6%	Hash Table String	Read
3084. Count Substrings Starting and Ending with Given Character	Medium	49.9%	Counting Math+1	Read
3085. Minimum Deletions to Make String K-Special	Medium	67.2%	Counting Greedy+3	Read
3086. Minimum Moves to Pick K Ones	Hard	21.6%	Array Greedy+2	Read
3087. Find Trending Hashtags	Medium	62.0%	Database	Read
3088. Make String Anti-palindrome	Hard	46.6%	Counting Sort Greedy+2	Read
3089. Find Bursty Behavior	Medium	39.4%	Database	Read
3090. Maximum Length Substring With Two Occurrences	Easy	77.4%	Hash Table Sliding Window+1	Read
3091. Apply Operations to Make Sum of Array Greater Than or Equal to k	Medium	44.2%	Enumeration Greedy+1	Read
3092. Most Frequent IDs	Medium	43.0%	Array Hash Table+2	Read
3093. Longest Common Suffix Queries	Hard	52.8%	Array String+1	Read
3094. Guess the Number Using Bitwise Questions II	Medium	83.0%	Bit Manipulation Interactive	Read
3095. Shortest Subarray With OR at Least K I	Easy	44.9%	Array Bit Manipulation+1	Read
3096. Minimum Levels to Gain More Points	Medium	40.4%	Array Prefix Sum	Read
3097. Shortest Subarray With OR at Least K II	Medium	50.5%	Array Bit Manipulation+1	Read
3098. Find the Sum of Subsequence Powers	Hard	25.1%	Array Dynamic Programming+1	Read
3099. Harshad Number	Easy	83.4%	Math	Read
3100. Water Bottles II	Medium	78.2%	Math Simulation	Read

#3051Easy

Find Candidates for Data Scientist Position

Database

Acceptance: 74.7%

#3052Hard

Maximize Items

Database

Acceptance: 72.0%

#3053Easy

Classifying Triangles by Lengths

Database

Acceptance: 50.3%

#3054Medium

Binary Tree Nodes

Database

Acceptance: 79.8%

#3055Medium

Top Percentile Fraud

Database

Acceptance: 58.1%

#3056Medium

Snaps Analysis

Database

Acceptance: 58.0%

#3057Hard

Employees Project Allocation

Database

Acceptance: 68.4%

#3058Medium

Friends With No Mutual Friends

Database

Acceptance: 49.4%

#3059Easy

Find All Unique Email Domains

Database

Acceptance: 69.0%

#3060Hard

User Activities within Time Bounds

Database

Acceptance: 40.6%

#3061Hard

Calculate Trapping Rain Water

Database

Acceptance: 81.1%

#3062Easy

Winner of the Linked List Game

Linked List

Acceptance: 77.6%

#3063Easy

Linked List Frequency

CountingHash TableLinked List

Acceptance: 85.8%

#3064Medium

Guess the Number Using Bitwise Questions I

Bit ManipulationInteractive

Acceptance: 89.0%

#3065Easy

Minimum Operations to Exceed Threshold Value I

Array

Acceptance: 86.7%

#3066Medium

Minimum Operations to Exceed Threshold Value II

ArrayHeap (Priority Queue)Simulation

Acceptance: 45.8%

#3067Medium

Count Pairs of Connectable Servers in a Weighted Tree Network

ArrayDepth-First SearchTree

Acceptance: 55.6%

#3068Hard

Find the Maximum Sum of Node Values

ArrayBit ManipulationDynamic Programming+3

Acceptance: 69.5%

#3069Easy

Distribute Elements Into Two Arrays I

ArraySimulation

Acceptance: 83.4%

#3070Medium

Count Submatrices with Top-Left Element and Sum Less Than k

ArrayMatrixPrefix Sum

Acceptance: 74.8%

#3071Medium

Minimum Operations to Write the Letter Y on a Grid

ArrayCountingHash Table+1

Acceptance: 63.9%

#3072Hard

Distribute Elements Into Two Arrays II

ArrayBinary Indexed TreeSegment Tree+1

Acceptance: 32.1%

#3073Medium

Maximum Increasing Triplet Value

ArrayOrdered Set

Acceptance: 35.7%

#3074Easy

Apple Redistribution into Boxes

ArrayGreedySorting

Acceptance: 78.5%

#3075Medium

Maximize Happiness of Selected Children

ArrayGreedySorting

Acceptance: 58.7%

#3076Medium

Shortest Uncommon Substring in an Array

ArrayHash TableString+1

Acceptance: 50.8%

#3077Hard

Maximum Strength of K Disjoint Subarrays

ArrayDynamic ProgrammingPrefix Sum

Acceptance: 28.2%

#3078Medium

Match Alphanumerical Pattern in Matrix I

ArrayHash TableMatrix+1

Acceptance: 64.6%

#3079Easy

Find the Sum of Encrypted Integers

ArrayMath

Acceptance: 74.7%

#3080Medium

Mark Elements on Array by Performing Queries

ArrayHash TableHeap (Priority Queue)+2

Acceptance: 49.1%

#3081Medium

Replace Question Marks in String to Minimize Its Value

CountingGreedyHash Table+3

Acceptance: 29.0%

#3082Hard

Find the Sum of the Power of All Subsequences

ArrayDynamic Programming

Acceptance: 38.1%

#3083Easy

Existence of a Substring in a String and Its Reverse

Hash TableString

Acceptance: 66.6%

#3084Medium

Count Substrings Starting and Ending with Given Character

CountingMathString

Acceptance: 49.9%

#3085Medium

Minimum Deletions to Make String K-Special

CountingGreedyHash Table+2

Acceptance: 67.2%

#3086Hard

Minimum Moves to Pick K Ones

ArrayGreedyPrefix Sum+1

Acceptance: 21.6%

#3087Medium

Find Trending Hashtags

Database

Acceptance: 62.0%

#3088Hard

Make String Anti-palindrome

Counting SortGreedySorting+1

Acceptance: 46.6%

#3089Medium

Find Bursty Behavior

Database

Acceptance: 39.4%

#3090Easy

Maximum Length Substring With Two Occurrences

Hash TableSliding WindowString

Acceptance: 77.4%

#3091Medium

Apply Operations to Make Sum of Array Greater Than or Equal to k

EnumerationGreedyMath

Acceptance: 44.2%

#3092Medium

Most Frequent IDs

ArrayHash TableHeap (Priority Queue)+1

Acceptance: 43.0%

#3093Hard

Longest Common Suffix Queries

ArrayStringTrie

Acceptance: 52.8%

#3094Medium

Guess the Number Using Bitwise Questions II

Bit ManipulationInteractive

Acceptance: 83.0%

#3095Easy

Shortest Subarray With OR at Least K I

ArrayBit ManipulationSliding Window

Acceptance: 44.9%

#3096Medium

Minimum Levels to Gain More Points

ArrayPrefix Sum

Acceptance: 40.4%

#3097Medium

Shortest Subarray With OR at Least K II

ArrayBit ManipulationSliding Window

Acceptance: 50.5%

#3098Hard

Find the Sum of Subsequence Powers

ArrayDynamic ProgrammingSorting

Acceptance: 25.1%

#3099Easy

Harshad Number

Math

Acceptance: 83.4%

#3100Medium

Water Bottles II

MathSimulation

Acceptance: 78.2%

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Master DSA with Step-by-Step Solutions

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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