[于是我默默地举报了你](https://www.luogu.org/discuss/show/152590)
by tobie @ 2019-11-10 09:41:13
？
by Rainy7 @ 2019-11-10 09:41:32
@[wanjingqi](/user/192044)
这个是错的程序，我在等大佬解释....
by k，火魂 @ 2019-11-10 09:49:36
@[wanjingqi](/user/192044)
我在等大佬改错
by k，火魂 @ 2019-11-10 09:49:54
~~这题不是二维前缀和么~~
by lingshi @ 2019-11-10 10:11:56