Leetcode刷题思路
算法思想题目分类
1.双指针类
- 167. Two Sum II - Input array is sorted (Easy)
- 633. Sum of Square Numbers (Easy)
- 345. Reverse Vowels of a String (Easy)
- 680. Valid Palindrome II (Easy)
- 88. Merge Sorted Array (Easy)
- 141. Linked List Cycle (Easy)
- 524. Longest Word in Dictionary through Deleting (Medium)
2.排序算法
- 215. Kth Largest Element in an Array (Medium)
- 347. Top K Frequent Elements (Medium)
- 451. Sort Characters By Frequency (Medium)
- 75. Sort Colors (Medium)
3.贪心算法
- 455. Assign Cookies (Easy)
- 435. Non-overlapping Intervals (Medium)
- 452. Minimum Number of Arrows to Burst Balloons (Medium)
- 406. Queue Reconstruction by Height(Medium)
- 121. Best Time to Buy and Sell Stock (Easy)
- 122. Best Time to Buy and Sell Stock II (Easy)
- 605. Can Place Flowers (Easy)
- 392. Is Subsequence (Medium)
- 665. Non-decreasing Array (Easy)
- 53. Maximum Subarray (Easy)
- 763. Partition Labels (Medium)
4.二分查找
- 69. Sqrt(x) (Easy)
- 744. Find Smallest Letter Greater Than Target (Easy)
- 540. Single Element in a Sorted Array (Medium)
- 278. First Bad Version (Easy)
- 153. Find Minimum in Rotated Sorted Array (Medium)
- 34. Find First and Last Position of Element in Sorted Array
5.分治算法
- 241. Different Ways to Add Parentheses (Medium)
- 95. Unique Binary Search Trees II (Medium)
6.搜索类算法
广搜类：
- 1091. Shortest Path in Binary Matrix(Medium)
- 279. Perfect Squares (Medium)
- 127. Word Ladder (Medium)
深搜类：
- 695. Max Area of Island (Medium)
- 200. Number of Islands (Medium)
- 547. Friend Circles (Medium)
- 130. Surrounded Regions (Medium)
- 417. Pacific Atlantic Water Flow (Medium)
回溯类：（其实也是深搜）
- 17. Letter Combinations of a Phone Number (Medium)
- 93. Restore IP Addresses(Medium)
- 79. Word Search (Medium)
- 257. Binary Tree Paths (Easy)
- 46. Permutations (Medium)
- 47. Permutations II (Medium)
- 77. Combinations (Medium)
- 39. Combination Sum (Medium)
- 40. Combination Sum II (Medium)
- 216. Combination Sum III (Medium)
- 78. Subsets (Medium)
- 90. Subsets II (Medium)
- 131. Palindrome Partitioning (Medium)
- 37. Sudoku Solver (Hard)
- 51. N-Queens (Hard)
7.动态规划类
斐波那契：
- 70. Climbing Stairs (Easy)
- 198. House Robber (Easy)
- 213. House Robber II (Medium)
矩阵路径：
- 64. Minimum Path Sum (Medium)
- 62. Unique Paths (Medium)
数组区间：
- 303. Range Sum Query - Immutable (Easy)
- 413. Arithmetic Slices (Medium)
分割整数：
- 343. Integer Break (Medim)
- 279. Perfect Squares(Medium)
- 91. Decode Ways (Medium)
最长递增子序列：
- 300. Longest Increasing Subsequence (Medium)
- 646. Maximum Length of Pair Chain (Medium)
- 376. Wiggle Subsequence (Medium)
最长公共子序列：
- 1143. Longest Common Subsequence
背包问题：
- 416. Partition Equal Subset Sum (Medium)
- 494. Target Sum (Medium)
- 474. Ones and Zeroes (Medium)
- 322. Coin Change (Medium)
- 518. Coin Change 2 (Medium)
- 139. Word Break (Medium)
- 377. Combination Sum IV (Medium)
股票交易：
- 309. Best Time to Buy and Sell Stock with Cooldown(Medium)
- 714. Best Time to Buy and Sell Stock with Transaction Fee (Medium)
- 123. Best Time to Buy and Sell Stock III (Hard)
- 188. Best Time to Buy and Sell Stock IV (Hard)
字符串编辑：
- 583. Delete Operation for Two Strings (Medium)
- 72. Edit Distance (Hard)
- 650. 2 Keys Keyboard (Medium)
7.数学类
- 204. Count Primes (Easy)
进制转换：
- 504. Base 7 (Easy)
- 405. Convert a Number to Hexadecimal (Easy)
- 168. Excel Sheet Column Title (Easy)
阶乘：
- 172. Factorial Trailing Zeroes (Easy)
字符串加减：
- 67. Add Binary (Easy)
- 415. Add Strings (Easy)
相遇问题：
- 462. Minimum Moves to Equal Array Elements II (Medium)
其他：
- 169. Majority Element (Easy)
- 367. Valid Perfect Square (Easy)
- 326. Power of Three (Easy)
- 238. Product of Array Except Self (Medium)
- 628. Maximum Product of Three Numbers (Easy)
总结：
小贴士：
刚开始刷题都会有困难，也可能第一题都做不出来，（其实刚开始我就是，哈哈），甚至还可能连题目都看不懂
不过没关系，刚接触都是这样的，不要着急，一点一点去理解，算法思想要养成然后去运用不是一个短暂的过程。
对比一天刷五题，但是没理解，还不如就刷了一题，但是理解透了。
个人建议：
刚开始不用羞于看别人的解答，可以看，如果好长时间了都没有思路，可以去借鉴一下别人的题解。
但是最重要的是，看了不等于会了，自己必须要再敲一遍，这时候也许会发现很多的问题，这些问题就是在懂了思想的情况下实现起来的问题。
只有自己在理解和实现都没有问题的情况下，才能算是掌握了，不能做思想的巨人。
这些归类的话是因为他们是基本类似的思想来解题，针对性的锻炼思维，在做完了一题之后还有类似的可以拿来训练，如果做题没有规律，思维跨度太大，很可能在做完下面的题就忘了上面的题
所以我习惯以这样归类的方式去刷题，分享给大家，供参考。
