感谢大佬提醒,但我还是错了,因为我理解错了,直接减掉了(蒟蒻自卑 by runtime_error @ 2018-12-28 02:12:35
感谢qwq >~~三年OI一场空~~ by z7z_Eta @ 2019-08-17 13:25:52