$n$ 太大了，不能遍历一遍
by qfpjm @ 2021-08-11 11:24:35
建议用数学方法，~~排列组合~~
by qfpjm @ 2021-08-11 11:25:19
@[Ted何家乐](/user/342868)
代码怎么写鸭
by yjh666654 @ 2021-08-11 12:51:32
@[Ted何家乐](/user/342868)
long long?
by yjh666654 @ 2021-08-11 12:52:08