dalao您需要一个前缀和优化
by Adove @ 2018-03-13 21:42:50
试试O2优化？
by Rocket_raccoon_ @ 2018-03-20 13:53:21
# [事实证明](https://www.luogu.org/recordnew/show/6656703)
只加了O2······
by ⚡GG⚡ @ 2018-04-06 21:40:42