1 Two Sum 2 5 array + set sort + two pointers 2 Add Two Numbers 3 4 linked list two pointers + math 3 Longest Substring Without Repeating Characters 3 2 string + hashtable two pointers 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 + heap sort + 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 + linked list + red-black tree sort + merge 57 Insert Interval 4 5 array + linked list + red-black tree sort + merge 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 + hashtable recursion + 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 + tree bfs + stack 104 Maximum Depth of Binary Tree 1 1 tree dfs 105 Construct Binary Tree from Preorder and Inorder Tr 3 3 array + tree dfs 106 Construct Binary Tree from Inorder and Postorder T 3 3 array + tree dfs 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 原文地址http://wwwx.cs.unc.edu/~zhew/Leetcoder/
============================================================================== 我喜欢程序员，他们单纯、固执、容易体会到成就感；面对压力，能够挑灯夜战不眠不休；面对困难，能够迎难而上挑战自我。他们也会感到困惑与傍徨，但每个程序员的心中都有一个比尔盖茨或是乔布斯的梦想“用智慧开创属于自己的事业”。我想说的是，其实我是一个程序员 ==============================================================================
LeetCode 问题汇总（算法，难度，频率）
最新推荐文章于 2025-07-03 20:11:39 发布
本文总结了LeetCode题库中经典算法题目及其难度级别、出现频率和主要涉及的数据结构与算法类型，帮助读者了解各类题目的特点及解决思路。
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