README.md

LeetCode算法归纳

我将LeetCode算法题按照标签整理了一些解题思路，下面会分别给出链接方便查看。同时，还我还贴出了一些刷题过程中记录的一些笔记。

目录

• Array
• BackTracking
• Binary Search
• Dynamic Programming
• Graph
• HashMap
• LinkedList
• Math
• Sort
• Stack
• String
• Tree
• TwoPointers
• Note

Array

• 1. Two Sum
• 4. Median of Two Sorted Arrays
• 18. 4Sum
• 26. Remove Duplicate from Sorted Array
• 31. Next Permutation
• 41. First Missing Positive
• 48. Rotate Image
• 53. Maximum Subarray
• 53. Spiral Matrix
• 59. Spiral Matrix II
• 88. Merge Sorted Array
• 119. Pascal's Triangle
• 120. Pascal's Triangle II
• 121. Best Time to Buy and Sell Stock(DP)
• 122. Best Time to Buy and Sell Stock II
• 167. Two Sum II - Input array is sorted
• 169. Majority Element
• 189. Rotate Array
• 206. Reverse Linked List
• 217. Contains Duplicate
• 238. Product of Array Except Self
• 268. Missing Number
• 283. Move Zeros
• 414. Third Maximum Number
• 448. Find All Number Disappeared in an Array
• 485. Max Consecutive Ones
• 532. K-diff Pairs in an Array
• 561. Array Partition I
• 566. Reshape the Matrix
• 581. Shortest Unsorted Continuous Subarray
• 605. Can Place Flowers
• 628. Maximum Product of Three Numbers
• 643. Maximum Average Subarray I
• 661. Image Smoother
• 665. Non-decreasing Array
• 674. Longest Continuous Increasing Subsequence
• 695. Max Area of Island
• 697. Degree of an Array
• 717. 1-bit and 2-bit Characters
• 724. Find Pivot Index

Back Tracking

• 17. Letter Combinations of a Phone Number
• 22. Generate Parentheses
• 37. Sudoku Solver
• 39. Combination Sum
• 40. Combination Sum II
• 46. Permutations
• 47. Permutations II
• 60. Permutation Sequence
• 77. Combinations
• 78. Subsets
• 401. Binary Watch

Binary Search

• 33. Search in Rotated Sorted Array
• 34. Search for a Range
• 50. Pow(x, n)
• 278. First Bad Version
• 374. Guess Number Higher of Lower
• 475. Heaters

Dynamic Programming

• 10. Regular Expression Matching
• 32. Longest Valid Parentheses
• 62. Unique Paths
• 63. Unique Paths II
• 64. Minimum Path Sum
• 70. Climbing Stairs
• 91. Decode Ways
• 198. House Robber
• 303. Range Sum Query - Immutable
• 746. Min Cost Climbing Stairs

Graph

• 133. Clone Graph

HashMap

• 30. Substring with Concatenation of All Words
• 36. Valid Sudoku
• 46. Group Anagrams
• 136. Single Number
• 202. Happy Number
• 204. Count Primes
• 205. Isomorphic Strings
• 242. Valid Anagram
• 290. Word Pattern
• 349. Intersection of Two Arrays
• 350. Intersection of Two Arrays II
• 387. First Unique Character in a String
• 389. Find the Difference
• 438. Find All Anagrams in a String
• 447. Number of Boomerangs
• 463. Island Perimeter
• 500. Keyboard Row
• 575. Distribute Candies
• 594. Longest Harmonious Subsequence
• 599. Minimum Index Sum of Two Lists
• 645. Set Mismatch
• 690. Employee Importance
• 720. Longest Word in Dictionary
• 734. Sentence Similarity

Linked List

• 19. Remove Nth Node From End of List
• 21. Merge Two Sorted Lists
• 25. Reverse Nodes in k-Group
• 23. Merge k Sorted Lists
• 83. Remove Duplicates from Sorted List
• 141. Linked List Cycle
• 160. Intersection of Two Linked Lists
• 203. Remove Linked List Elements
• 234. Palindrome Linked List
• 237. Delete Node in a Linked List
• 445. Add Two Numbers II
• 725. Split Linked List in Parts

Math

• 2. Add Two Numbers
• 7. Reverse Integer
• 9. Palindrome Number
• 13. Roman to Integer
• 43. Multiply Strings
• 67. Add Binary
• 69. Sqrt(x)
• 168. Excel Sheet Column Title
• 171. Excel Sheet Column Number
• 172. Factorial Trailing Zeroes
• 231. Power of Two
• 258. Add Digits
• 263. Ugly Number
• 326. Power of Three
• 367. Valid Perfect Square
• 400. Nth Digit
• 415. Add Strings
• 441. Arranging Coins
• 453. Minimum Moves to Equal Array Elements
• 507. Perfect Number
• 598. Range Addition II
• 633. Sum of Square Numbers
• 728. Self Dividing Numbers

Sort

• 56. Merge Intervals
• 75. Sort Colors
• 147. Insertion Sort List
• 148. Sort List
• 179. Largest Number
• 274. H-Index

Stack

• 225. Implement Stack using Queues
• 232. Implement Queue using Stacks
• 496. Next Greater Element I
• 682. Baseball Game

String

• 5. Longest Palindromic Substring
• 12. Integer to Roman
• 14. Longest Common Prefix
• 20. Valid Parentheses
• 38. Count and Say
• 58. Length of Last Word
• 345. Reverse Vowels of a String
• 383. Ransom Note
• 434. Number of Segments in a String
• 443. String Compression
• 459. Repeated Substring Pattern
• 520. Detect Capital
• 541. Reverse String II
• 551. Student Attendance Record I
• 557. Reverse Words in a String III
• 606. Construct String from Binary Tree
• 657. Judge Route Circle
• 680. Valid Palindrome II
• 686. Repeated String Match
• 696. Count Binary Substrings
• 744. Find Smallest Letter Greater Than Target
• 784. Letter Case Permutation
• 796. Rotate String

Tree

• 94. Binary Tree Inorder Traversal
• 95. Unique Binary Search Trees II
• 96. Unique Binary Search Trees
• 98. Validate Binary Search Tree
• 100. Same Tree
• 102. Binary Tree Level Order Traversal
• 103. Binary Tree Zigzag Level Order Traversal
• 105. Construct Binary Tree from Preorder and Inorder Traversal
• 106. Construct Binary Tree from Inorder and Postorder Traversal
• 108. Convert Sorted Array to Binary Search Tree
• 110. Balanced Binary Tree
• 111. Minimum Depth of Binary Tree
• 637. Average of Levels in Binary Tree

Two Pointers

• 3. Longest Substring Without Repeating Characters
• 11. Container With Most Water
• 15. 3Sum
• 16. 3Sum Closest
• 19. Remove Nth Node From End of List
• 24. Swap Nodes in Paris
• 28. Implement strStr()
• 31. Next Permutation
• 125. Valid Palindrome
• 344. Reverse String

Note

• 一些Java使用中的技巧
• 刷LeetCode时遇到的一些知识点：
• 排序
• 矩阵的转置变换、翻转行/列、旋转