1/24~3/24 60天刷题全力冲冲冲

# 2020/2/27

340. Longest Substring with At Most K Distinct Characters

240. Search a 2D Matrix II

10. Regular Expression Matching

# 2020/2/28

75. Sort Colors
ndex 从左到右扫描每个数，如果碰到 0 就丢给 left，碰到 2 就丢给 right。碰到 1 就跳过不管

13. Roman to Integer
从右往左去算数字

133. Clone Graph
用一个 map 去存放关系即可

19. Remove Nth Node From End of List
注意要用 dummy node

7. Reverse Integer
注意 overflow 的情况

# 2020/2/29

415. Add Strings
正常相加

346. Moving Average from Data Stream
用一个数组存 window

636. Exclusive Time of Functions
注意要加1，使得计算整个长度

207. Course Schedule
BFS + 拓扑排序

168. Excel Sheet Column Title
注意要先减1再做转换

142. Linked List Cycle II

# 2020/3/1

695. Max Area of Island
经典 BFS

253. Meeting Rooms II
扫描线

277. Find the Celebrity

24. Swap Nodes in Pairs

136. Single Number

# 2020/3/3

14. Longest Common Prefix
dp

212. Word Search II
Hash set + dfs

328. Odd Even Linked List
注意这里说的不是 value 的值

79. Word Search
DFS + hash map

15. 3Sum

# 2020/3/4

11. Container With Most Water
双指针

124. Binary Tree Maximum Path Sum
分治法

210. Course Schedule II
拓扑

78. Subsets
先排序后 DFS

235. Lowest Common Ancestor of a Binary Search Tree
简单的分治，判断两个节点是否在同一边或者在两边

楼主厉害！

# 2020/3/5

242. Valid Anagram

287. Find the Duplicate Number

125. Valid Palindrome

想问下楼主是刷到第几遍复习的时候可以达到这个速度呀。。感觉一天好多

# 2020/3/6

165. Compare Version Numbers
从左到右对比

117. Populating Next Right Pointers in Each Node II
分层 BFS

160. Intersection of Two Linked Lists

179. Largest Number
两个 key 对比去排序

50. Pow(x, n)
递归解法