https://www.luogu.com.cn/record/56111018 -> https://www.luogu.com.cn/blog/yummy-loves-114514/solution-p1002
https://www.luogu.com.cn/record/56111860 -> https://www.luogu.com.cn/blog/oyokuaizi/solution-p1014
https://www.luogu.com.cn/record/56113474 -> https://www.luogu.com.cn/blog/user20297/solution-p1085
