[三四分钟一个题](https://www.luogu.org/problemnew/show/P2042)
by iotang @ 2018-03-06 22:25:59
@[IsaacOriTang](/space/show?uid=44176) 嘛。。。这的确也算是个板子题qwq
by Running_Coder @ 2018-03-06 22:37:38