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
1077. Project Employees III	Medium	76.8%	Database	Read
1079. Letter Tile Possibilities	Medium	83.5%	Backtracking Counting+2	Read
1080. Insufficient Nodes in Root to Leaf Paths	Medium	55.6%	Binary Tree Depth-First Search+1	Read
1081. Smallest Subsequence of Distinct Characters	Medium	70.6%	Greedy Monotonic Stack+2	Read
1087. Brace Expansion	Medium	66.5%	Backtracking Breadth-First Search+1	Read
1090. Largest Values From Labels	Medium	64.7%	Array Counting+3	Read
1091. Shortest Path in Binary Matrix	Medium	51.8%	Array Breadth-First Search+1	Read
1093. Statistics from a Large Sample	Medium	43.6%	Array Math+1	Read
1094. Car Pooling	Medium	56.5%	Array Heap (Priority Queue)+3	Read
1098. Unpopular Books	Medium	43.3%	Database	Read
1100. Find K-Length Substrings With No Repeated Characters	Medium	76.5%	Hash Table Sliding Window+1	Read
1101. The Earliest Moment When Everyone Become Friends	Medium	66.0%	Array Sorting+1	Read
1102. Path With Maximum Minimum Value	Medium	54.6%	Array Binary Search+5	Read
1104. Path In Zigzag Labelled Binary Tree	Medium	75.9%	Binary Tree Math+1	Read
1105. Filling Bookcase Shelves	Medium	68.7%	Array Dynamic Programming	Read
1107. New Users Daily Count	Medium	44.7%	Database	Read
1109. Corporate Flight Bookings	Medium	68.7%	Array Prefix Sum	Read
1110. Delete Nodes And Return Forest	Medium	72.4%	Array Binary Tree+3	Read
1111. Maximum Nesting Depth of Two Valid Parentheses Strings	Medium	72.1%	Stack String	Read
1112. Highest Grade For Each Student	Medium	70.8%	Database	Read
1115. Print FooBar Alternately	Medium	67.7%	Concurrency	Read
1116. Print Zero Even Odd	Medium	62.0%	Concurrency	Read
1117. Building H2O	Medium	57.1%	Concurrency	Read
1120. Maximum Average Subtree	Medium	66.7%	Binary Tree Depth-First Search+1	Read
1123. Lowest Common Ancestor of Deepest Leaves	Medium	79.5%	Binary Tree Breadth-First Search+3	Read
1124. Longest Well-Performing Interval	Medium	37.9%	Array Hash Table+3	Read
1126. Active Businesses	Medium	65.8%	Database	Read
1129. Shortest Path with Alternating Colors	Medium	47.8%	Breadth-First Search Graph	Read
1130. Minimum Cost Tree From Leaf Values	Medium	67.7%	Array Dynamic Programming+3	Read
1131. Maximum of Absolute Value Expression	Medium	48.4%	Array Math	Read
1132. Reported Posts II	Medium	32.3%	Database	Read
1135. Connecting Cities With Minimum Cost	Medium	63.5%	Graph Heap (Priority Queue)+2	Read
1136. Parallel Courses	Medium	62.1%	Graph Topological Sort	Read
1138. Alphabet Board Path	Medium	51.5%	Hash Table String	Read
1139. Largest 1-Bordered Square	Medium	52.1%	Array Dynamic Programming+1	Read
1140. Stone Game II	Medium	75.8%	Array Dynamic Programming+3	Read
1143. Longest Common Subsequence	Medium	59.6%	Dynamic Programming String	Read
1144. Decrease Elements To Make Array Zigzag	Medium	49.7%	Array Greedy	Read
1145. Binary Tree Coloring Game	Medium	52.9%	Binary Tree Depth-First Search+1	Read
1146. Snapshot Array	Medium	36.8%	Array Binary Search+2	Read
1149. Article Views II	Medium	47.1%	Database	Read
1151. Minimum Swaps to Group All 1's Together	Medium	61.2%	Array Sliding Window	Read
1152. Analyze User Website Visit Pattern	Medium	44.3%	Array Hash Table+1	Read
1155. Number of Dice Rolls With Target Sum	Medium	62.2%	Dynamic Programming	Read
1156. Swap For Longest Repeated Character Substring	Medium	44.9%	Hash Table Sliding Window+1	Read
1158. Market Analysis I	Medium	57.2%	Database	Read
1161. Maximum Level Sum of a Binary Tree	Medium	70.0%	Binary Tree Breadth-First Search+2	Read
1162. As Far from Land as Possible	Medium	52.2%	Array Breadth-First Search+2	Read
1164. Product Price at a Given Date	Medium	57.0%	Database	Read
1166. Design File System	Medium	65.1%	Design Hash Table+2	Read

#1077Medium

Project Employees III

Database

Acceptance: 76.8%

#1079Medium

Letter Tile Possibilities

BacktrackingCountingHash Table+1

Acceptance: 83.5%

#1080Medium

Insufficient Nodes in Root to Leaf Paths

Binary TreeDepth-First SearchTree

Acceptance: 55.6%

#1081Medium

Smallest Subsequence of Distinct Characters

GreedyMonotonic StackStack+1

Acceptance: 70.6%

#1087Medium

Brace Expansion

BacktrackingBreadth-First SearchString

Acceptance: 66.5%

#1090Medium

Largest Values From Labels

ArrayCountingGreedy+2

Acceptance: 64.7%

#1091Medium

Shortest Path in Binary Matrix

ArrayBreadth-First SearchMatrix

Acceptance: 51.8%

#1093Medium

Statistics from a Large Sample

ArrayMathProbability and Statistics

Acceptance: 43.6%

#1094Medium

Car Pooling

ArrayHeap (Priority Queue)Prefix Sum+2

Acceptance: 56.5%

#1098Medium

Unpopular Books

Database

Acceptance: 43.3%

#1100Medium

Find K-Length Substrings With No Repeated Characters

Hash TableSliding WindowString

Acceptance: 76.5%

#1101Medium

The Earliest Moment When Everyone Become Friends

ArraySortingUnion Find

Acceptance: 66.0%

#1102Medium

Path With Maximum Minimum Value

ArrayBinary SearchBreadth-First Search+4

Acceptance: 54.6%

#1104Medium

Path In Zigzag Labelled Binary Tree

Binary TreeMathTree

Acceptance: 75.9%

#1105Medium

Filling Bookcase Shelves

ArrayDynamic Programming

Acceptance: 68.7%

#1107Medium

New Users Daily Count

Database

Acceptance: 44.7%

#1109Medium

Corporate Flight Bookings

ArrayPrefix Sum

Acceptance: 68.7%

#1110Medium

Delete Nodes And Return Forest

ArrayBinary TreeDepth-First Search+2

Acceptance: 72.4%

#1111Medium

Maximum Nesting Depth of Two Valid Parentheses Strings

StackString

Acceptance: 72.1%

#1112Medium

Highest Grade For Each Student

Database

Acceptance: 70.8%

#1115Medium

Print FooBar Alternately

Concurrency

Acceptance: 67.7%

#1116Medium

Print Zero Even Odd

Concurrency

Acceptance: 62.0%

#1117Medium

Building H2O

Concurrency

Acceptance: 57.1%

#1120Medium

Maximum Average Subtree

Binary TreeDepth-First SearchTree

Acceptance: 66.7%

#1123Medium

Lowest Common Ancestor of Deepest Leaves

Binary TreeBreadth-First SearchDepth-First Search+2

Acceptance: 79.5%

#1124Medium

Longest Well-Performing Interval

ArrayHash TableMonotonic Stack+2

Acceptance: 37.9%

#1126Medium

Active Businesses

Database

Acceptance: 65.8%

#1129Medium

Shortest Path with Alternating Colors

Breadth-First SearchGraph

Acceptance: 47.8%

#1130Medium

Minimum Cost Tree From Leaf Values

ArrayDynamic ProgrammingGreedy+2

Acceptance: 67.7%

#1131Medium

Maximum of Absolute Value Expression

ArrayMath

Acceptance: 48.4%

#1132Medium

Reported Posts II

Database

Acceptance: 32.3%

#1135Medium

Connecting Cities With Minimum Cost

GraphHeap (Priority Queue)Minimum Spanning Tree+1

Acceptance: 63.5%

#1136Medium

Parallel Courses

GraphTopological Sort

Acceptance: 62.1%

#1138Medium

Alphabet Board Path

Hash TableString

Acceptance: 51.5%

#1139Medium

Largest 1-Bordered Square

ArrayDynamic ProgrammingMatrix

Acceptance: 52.1%

#1140Medium

Stone Game II

ArrayDynamic ProgrammingGame Theory+2

Acceptance: 75.8%

#1143Medium

Longest Common Subsequence

Dynamic ProgrammingString

Acceptance: 59.6%

#1144Medium

Decrease Elements To Make Array Zigzag

ArrayGreedy

Acceptance: 49.7%

#1145Medium

Binary Tree Coloring Game

Binary TreeDepth-First SearchTree

Acceptance: 52.9%

#1146Medium

Snapshot Array

ArrayBinary SearchDesign+1

Acceptance: 36.8%

#1149Medium

Article Views II

Database

Acceptance: 47.1%

#1151Medium

Minimum Swaps to Group All 1's Together

ArraySliding Window

Acceptance: 61.2%

#1152Medium

Analyze User Website Visit Pattern

ArrayHash TableSorting

Acceptance: 44.3%

#1155Medium

Number of Dice Rolls With Target Sum

Dynamic Programming

Acceptance: 62.2%

#1156Medium

Swap For Longest Repeated Character Substring

Hash TableSliding WindowString

Acceptance: 44.9%

#1158Medium

Market Analysis I

Database

Acceptance: 57.2%

#1161Medium

Maximum Level Sum of a Binary Tree

Binary TreeBreadth-First SearchDepth-First Search+1

Acceptance: 70.0%

#1162Medium

As Far from Land as Possible

ArrayBreadth-First SearchDynamic Programming+1

Acceptance: 52.2%

#1164Medium

Product Price at a Given Date

Database

Acceptance: 57.0%

#1166Medium

Design File System

DesignHash TableString+1

Acceptance: 65.1%

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