选出来比较合适的博客
https://blog.csdn.net/Tony5t4rk/article/details/80490711
https://blog.csdn.net/Game_Acm/article/details/80480968
https://blog.csdn.net/weixin_39453270/article/details/80579640
hdu 6287
原文：https://www.cnblogs.com/Aiahtwo/p/10496987.html
