https://www.luogu.com.cn/record/102197502 --> https://www.luogu.com.cn/blog/Thinking/solution-p1173

https://www.luogu.com.cn/record/102197590 --> https://www.luogu.com.cn/blog/George1123/solution-p1526

https://www.luogu.com.cn/record/102198049 --> https://www.luogu.com.cn/blog/Kelin/solution-p1587 第一个代码