> kkk：理论上需要AC本题，但是也允许一些非完美的做法，需要详细阐述。
by ztz11 @ 2018-09-28 14:30:07
@[ぶらそけ](/space/show?uid=56556)
by ztz11 @ 2018-09-28 14:30:12
@[ztz11](/space/show?uid=52176) 谢了
by NULL0x7f @ 2018-09-28 14:31:31
~~哇神奇~~
~~https://www.luogu.org/record/show?rid=8828322~~
by 蒟蒻lxy @ 2018-10-06 23:40:42