Solution -「营业」「ABC 170D」Not Divisible
DescriptionLink.给出一个长度为 $n$ 的序列 $a$,求 $\sum_{i=1}^{n}[\forall j\in[1,i)\cup(i,n],a_{j}\nmid a_{i}...
In mathematics you don't understand things, you just get used to them.
In mathematics you don't understand things, you just get used to them.