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
51. N-Queens	Hard	76.3%	Array Backtracking	Read
52. N-Queens II	Hard	78.9%	Backtracking	Read
53. Maximum Subarray	Medium	53.7%	Array Divide and Conquer+1	Read
54. Spiral Matrix	Medium	57.6%	Array Matrix+1	Read
55. Jump Game	Medium	41.2%	Array Dynamic Programming+1	Read
56. Merge Intervals	Medium	52.6%	Array Sorting	Read
57. Insert Interval	Medium	45.5%	Array	Read
58. Length of Last Word	Easy	59.7%	String	Read
59. Spiral Matrix II	Medium	75.4%	Array Matrix+1	Read
60. Permutation Sequence	Hard	54.3%	Math Recursion	Read
61. Rotate List	Medium	43.1%	Linked List Two Pointers	Read
62. Unique Paths	Medium	67.3%	Combinatorics Dynamic Programming+1	Read
63. Unique Paths II	Medium	44.9%	Array Dynamic Programming+1	Read
64. Minimum Path Sum	Medium	68.6%	Array Dynamic Programming+1	Read
65. Valid Number	Hard	23.3%	String	Read
66. Plus One	Easy	50.3%	Array Math	Read
67. Add Binary	Easy	58.4%	Bit Manipulation Math+2	Read
68. Text Justification	Hard	51.8%	Array Simulation+1	Read
69. Sqrt(x)	Easy	42.2%	Binary Search Math	Read
70. Climbing Stairs	Easy	54.0%	Dynamic Programming Math+1	Read
71. Simplify Path	Medium	51.4%	Stack String	Read
72. Edit Distance	Medium	60.9%	Dynamic Programming String	Read
73. Set Matrix Zeroes	Medium	63.2%	Array Hash Table+1	Read
74. Search a 2D Matrix	Medium	54.4%	Array Binary Search+1	Read
75. Sort Colors	Medium	69.9%	Array Sorting+1	Read
76. Minimum Window Substring	Hard	48.3%	Hash Table Sliding Window+1	Read
77. Combinations	Medium	74.9%	Backtracking	Read
78. Subsets	Medium	82.7%	Array Backtracking+1	Read
79. Word Search	Medium	48.2%	Array Backtracking+2	Read
80. Remove Duplicates from Sorted Array II	Medium	65.0%	Array Two Pointers	Read
81. Search in Rotated Sorted Array II	Medium	40.4%	Array Binary Search	Read
82. Remove Duplicates from Sorted List II	Medium	52.2%	Linked List Two Pointers	Read
83. Remove Duplicates from Sorted List	Easy	57.0%	Linked List	Read
84. Largest Rectangle in Histogram	Hard	50.7%	Array Monotonic Stack+1	Read
85. Maximal Rectangle	Hard	59.5%	Array Dynamic Programming+3	Read
86. Partition List	Medium	62.0%	Linked List Two Pointers	Read
87. Scramble String	Hard	45.3%	Dynamic Programming String	Read
88. Merge Sorted Array	Easy	55.7%	Array Sorting+1	Read
89. Gray Code	Medium	65.6%	Backtracking Bit Manipulation+1	Read
90. Subsets II	Medium	61.7%	Array Backtracking+1	Read
91. Decode Ways	Medium	38.3%	Dynamic Programming String	Read
92. Reverse Linked List II	Medium	52.4%	Linked List	Read
93. Restore IP Addresses	Medium	56.7%	Backtracking String	Read
94. Binary Tree Inorder Traversal	Easy	80.4%	Binary Tree Depth-First Search+2	Read
95. Unique Binary Search Trees II	Medium	63.3%	Backtracking Binary Search Tree+3	Read
96. Unique Binary Search Trees	Medium	64.0%	Binary Search Tree Binary Tree+3	Read
97. Interleaving String	Medium	44.4%	Dynamic Programming String	Read
98. Validate Binary Search Tree	Medium	36.1%	Binary Search Tree Binary Tree+2	Read
99. Recover Binary Search Tree	Medium	60.9%	Binary Search Tree Binary Tree+2	Read
100. Same Tree	Easy	68.0%	Binary Tree Breadth-First Search+2	Read

#51Hard

N-Queens

ArrayBacktracking

Acceptance: 76.3%

#52Hard

N-Queens II

Backtracking

Acceptance: 78.9%

#53Medium

Maximum Subarray

ArrayDivide and ConquerDynamic Programming

Acceptance: 53.7%

#54Medium

Spiral Matrix

ArrayMatrixSimulation

Acceptance: 57.6%

#55Medium

Jump Game

ArrayDynamic ProgrammingGreedy

Acceptance: 41.2%

#56Medium

Merge Intervals

ArraySorting

Acceptance: 52.6%

#57Medium

Insert Interval

Array

Acceptance: 45.5%

#58Easy

Length of Last Word

String

Acceptance: 59.7%

#59Medium

Spiral Matrix II

ArrayMatrixSimulation

Acceptance: 75.4%

#60Hard

Permutation Sequence

MathRecursion

Acceptance: 54.3%

#61Medium

Rotate List

Linked ListTwo Pointers

Acceptance: 43.1%

#62Medium

Unique Paths

CombinatoricsDynamic ProgrammingMath

Acceptance: 67.3%

#63Medium

Unique Paths II

ArrayDynamic ProgrammingMatrix

Acceptance: 44.9%

#64Medium

Minimum Path Sum

ArrayDynamic ProgrammingMatrix

Acceptance: 68.6%

#65Hard

Valid Number

String

Acceptance: 23.3%

#66Easy

Plus One

ArrayMath

Acceptance: 50.3%

#67Easy

Add Binary

Bit ManipulationMathSimulation+1

Acceptance: 58.4%

#68Hard

Text Justification

ArraySimulationString

Acceptance: 51.8%

#69Easy

Sqrt(x)

Binary SearchMath

Acceptance: 42.2%

#70Easy

Climbing Stairs

Dynamic ProgrammingMathMemoization

Acceptance: 54.0%

#71Medium

Simplify Path

StackString

Acceptance: 51.4%

#72Medium

Edit Distance

Dynamic ProgrammingString

Acceptance: 60.9%

#73Medium

Set Matrix Zeroes

ArrayHash TableMatrix

Acceptance: 63.2%

#74Medium

Search a 2D Matrix

ArrayBinary SearchMatrix

Acceptance: 54.4%

#75Medium

Sort Colors

ArraySortingTwo Pointers

Acceptance: 69.9%

#76Hard

Minimum Window Substring

Hash TableSliding WindowString

Acceptance: 48.3%

#77Medium

Combinations

Backtracking

Acceptance: 74.9%

#78Medium

Subsets

ArrayBacktrackingBit Manipulation

Acceptance: 82.7%

#79Medium

Word Search

ArrayBacktrackingMatrix+1

Acceptance: 48.2%

#80Medium

Remove Duplicates from Sorted Array II

ArrayTwo Pointers

Acceptance: 65.0%

#81Medium

Search in Rotated Sorted Array II

ArrayBinary Search

Acceptance: 40.4%

#82Medium

Remove Duplicates from Sorted List II

Linked ListTwo Pointers

Acceptance: 52.2%

#83Easy

Remove Duplicates from Sorted List

Linked List

Acceptance: 57.0%

#84Hard

Largest Rectangle in Histogram

ArrayMonotonic StackStack

Acceptance: 50.7%

#85Hard

Maximal Rectangle

ArrayDynamic ProgrammingMatrix+2

Acceptance: 59.5%

#86Medium

Partition List

Linked ListTwo Pointers

Acceptance: 62.0%

#87Hard

Scramble String

Dynamic ProgrammingString

Acceptance: 45.3%

#88Easy

Merge Sorted Array

ArraySortingTwo Pointers

Acceptance: 55.7%

#89Medium

Gray Code

BacktrackingBit ManipulationMath

Acceptance: 65.6%

#90Medium

Subsets II

ArrayBacktrackingBit Manipulation

Acceptance: 61.7%

#91Medium

Decode Ways

Dynamic ProgrammingString

Acceptance: 38.3%

#92Medium

Reverse Linked List II

Linked List

Acceptance: 52.4%

#93Medium

Restore IP Addresses

BacktrackingString

Acceptance: 56.7%

#94Easy

Binary Tree Inorder Traversal

Binary TreeDepth-First SearchStack+1

Acceptance: 80.4%

#95Medium

Unique Binary Search Trees II

BacktrackingBinary Search TreeBinary Tree+2

Acceptance: 63.3%

#96Medium

Unique Binary Search Trees

Binary Search TreeBinary TreeDynamic Programming+2

Acceptance: 64.0%

#97Medium

Interleaving String

Dynamic ProgrammingString

Acceptance: 44.4%

#98Medium

Validate Binary Search Tree

Binary Search TreeBinary TreeDepth-First Search+1

Acceptance: 36.1%

#99Medium

Recover Binary Search Tree

Binary Search TreeBinary TreeDepth-First Search+1

Acceptance: 60.9%

#100Easy

Same Tree

Binary TreeBreadth-First SearchDepth-First Search+1

Acceptance: 68.0%

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