补充：
数据范围：n<=100，题面中并没有说明m的大小
@[chen_zhe](https://www.luogu.org/space/show?uid=8457)
by henry_y @ 2018-04-26 13:41:40
@[chen_zhe](/space/show?uid=8457)
by pufanyi @ 2018-04-27 10:38:23
@[yjjr](/space/show?uid=5088)
@[zcysky](/space/show?uid=2978)
@cy
by pufanyi @ 2018-04-27 10:39:17
@[icy](/space/show?uid=20487)
by pufanyi @ 2018-04-27 10:39:27
@[yyy2015c01](/space/show?uid=5846)
by icy @ 2018-04-28 21:39:55
@[chen_zhe](/space/show?uid=8457)
by n0000000000o @ 2018-08-05 21:00:03