leetcode高频题表

leetcode高频题目表

ID Question Diff Freq Data Structure Algorithms
1 Two Sum 2 5 array sort
set Two Pointers
2 Add Two Numbers 3 4 linked list Two Pointers
Math
3 Longest Substring Without Repeating Characters 3 2 string Two Pointers
hashtable
4 Median of Two Sorted Arrays 5 3 array Binary Search
5 Longest Palindromic Substring 4 2 string
6 ZigZag Conversion 3 1 string
7 Reverse Integer 2 3 Math
8 String to Integer (atoi) 2 5 string Math
9 Palindrome Number 2 2 Math
10 Regular Expression Matching 5 3 string Recursion
DP
11 Container With Most Water 3 2 array Two Pointers
12 Integer to Roman 3 4 Math
13 Roman to Integer 2 4 Math
14 Longest Common Prefix 2 1 string
15 3Sum 3 5 array Two Pointers
16 3Sum Closest 3 1 array Two Pointers
17 Letter Combinations of a Phone Number 3 3 string DFS
18 4Sum 3 2 array
19 Remove Nth Node From End of List 2 3 linked list Two Pointers
20 Valid Parentheses 2 5 string Stack
21 Merge Two Sorted Lists 2 5 linked list sort
Two Pointers
merge
22 Generate Parentheses 3 4 string DFS
23 Merge k Sorted Lists 3 4 linked list sort
heap Two Pointers
merge
24 Swap Nodes in Pairs 2 4 linked list
25 Reverse Nodes in k-Group 4 2 linked list Recursion
Two Pointers
26 Remove Duplicates from Sorted Array 1 3 array Two Pointers
27 Remove Element 1 4 array Two Pointers
28 Implement strStr() 4 5 string Two Pointers
KMP
rolling hash
29 Divide Two Integers 4 3 Binary Search
Math
30 Substring with Concatenation of All Words 3 1 string Two Pointers
31 Next Permutation 5 2 array permutation
32 Longest Valid Parentheses 4 1 string DP
33 Search in Rotated Sorted Array 4 3 array Binary Search
34 Search for a Range 4 3 array Binary Search
35 Search Insert Position 2 2 array
36 Valid Sudoku 2 2 array
37 Sudoku Solver 4 2 array DFS
38 Count and Say 2 2 string Two Pointers
39 Combination Sum 3 3 array combination
40 Combination Sum II 4 2 array combination
41 First Missing Positive 5 2 array sort
42 Trapping Rain Water 4 2 array Two Pointers
Stack
43 Multiply Strings 4 3 string Two Pointers
Math
44 Wildcard Matching 5 3 string Recursion
DP
greedy
45 Jump Game II 4 2 array
46 Permutations 3 4 array permutation
47 Permutations II 4 2 array permutation
48 Rotate Image 4 2 array
49 Anagrams 3 4 string
hashtable
50 Pow(x, n) 3 5 Binary Search
Math
51 N-Queens 4 3 array DFS
52 N-Queens II 4 3 array DFS
53 Maximum Subarray 3 3 array DP
54 Spiral Matrix 4 2 array
55 Jump Game 3 2 array
56 Merge Intervals 4 5 array sort
linked list merge
red-black tree
57 Insert Interval 4 5 array sort
linked list merge
red-black tree
58 Length of Last Word 1 1 string
59 Spiral Matrix II 3 2 array
60 Permutation Sequence 5 1 permutation
Math
61 Rotate List 3 2 linked list Two Pointers
62 Unique Paths 2 3 array DP
63 Unique Paths II 3 3 array DP
64 Minimum Path Sum 3 3 array DP
65 Valid Number 2 5 string Math
66 Plus One 1 2 array Math
67 Add Binary 2 4 string Two Pointers
Math
68 Text Justification 4 2 string
69 Sqrt(x) 4 4 Binary Search
70 Climbing Stairs 2 5 DP
71 Simplify Path 3 1 string Stack
72 Edit Distance 4 3 string DP
73 Set Matrix Zeroes 3 5 array
74 Search a 2D Matrix 3 3 array Binary Search
75 Sort Colors 4 2 array sort
Two Pointers
76 Minimum Window Substring 4 2 string Two Pointers
77 Combinations 3 4 combination
78 Subsets 3 4 array Recursion
combination
79 Word Search 3 4 array DFS
80 Remove Duplicates from Sorted Array II 2 2 array Two Pointers
81 Search in Rotated Sorted Array II 5 3 array Binary Search
82 Remove Duplicates from Sorted List II 3 3 linked list Recursion
Two Pointers
83 Remove Duplicates from Sorted List 1 3 linked list
84 Largest Rectangle in Histogram 5 2 array Stack
85 Maximal Rectangle 5 1 array DP
Stack
86 Partition List 3 3 linked list Two Pointers
87 Scramble String 5 2 string Recursion
DP
88 Merge Sorted Array 2 5 array Two Pointers
merge
89 Gray Code 4 2 combination
90 Subsets II 4 2 array Recursion
combination
91 Decode Ways 3 4 string Recursion
DP
92 Reverse Linked List II 3 2 linked list Two Pointers
93 Restore IP Addresses 3 3 string DFS
94 Binary Tree Inorder Traversal 4 3 tree Recursion
hashtable morris
Stack
95 Unique Binary Search Trees II 4 1 tree DP
DFS
96 Unique Binary Search Trees 3 1 tree DP
97 Interleaving String 5 2 string Recursion
DP
98 Validate Binary Search Tree 3 5 tree DFS
99 Recover Binary Search Tree 4 2 tree DFS
100 Same Tree 1 1 tree DFS
101 Symmetric Tree 1 2 tree DFS
102 Binary Tree Level Order Traversal 3 4 tree BFS
103 Binary Tree Zigzag Level Order Traversal 4 3 queue BFS
tree Stack
104 Maximum Depth of Binary Tree 1 1 tree DFS
105 Construct Binary Tree from Preorder and Inorder Tr 3 3 array DFS
tree
106 Construct Binary Tree from Inorder and Postorder T 3 3 array DFS
tree
107 Binary Tree Level Order Traversal II 3 1 tree BFS
108 Convert Sorted Array to Binary Search Tree 2 3 tree DFS
109 Convert Sorted List to Binary Search Tree 4 3 linked list Recursion
Two Pointers
110 Balanced Binary Tree 1 2 tree DFS
111 Minimum Depth of Binary Tree 1 1 tree DFS
112 Path Sum 1 3 tree DFS
113 Path Sum II 2 2 tree DFS
114 Flatten Binary Tree to Linked List 3 3 tree Recursion
Stack
115 Distinct Subsequences 4 2 string DP
116 Populating Next Right Pointers in Each Node 3 3 tree DFS
117 Populating Next Right Pointers in Each Node II 4 2 tree DFS
118 Pascal’s Triangle 2 1 array
119 Pascal’s Triangle II 2 1 array
120 Triangle 3 1 array DP
121 Best Time to Buy and Sell Stock 2 1 array DP
122 Best Time to Buy and Sell Stock II 3 1 array greedy
123 Best Time to Buy and Sell Stock III 4 1 array DP
124 Binary Tree Maximum Path Sum 4 2 tree DFS
125 Valid Palindrome 2 5 string Two Pointers
126 Word Ladder II 1 1
127 Word Ladder 3 5 graph BFS
shortest path
128 Longest Consecutive Sequence 4 3 array
129 Sum Root to Leaf Numbers 2 4 tree DFS
130 Surrounded Regions 4 3 array BFS
DFS
131 Palindrome Partitioning 3 4 string DFS
132 Palindrome Partitioning II 4 3 string DP
Author: NYY
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