0-30-0,数学还只打了暴力，菜就多练Problem1.facsum省流:\(f(n)=(\sum\limits_{d\midn}\varphi(d))^m(\sum\limits_{d\midn}\sigma_0(d)\mu(\frac{n}{d})\frac{n}{d})\)求\(\sum\limits_{i=1}^nf(i)\bmod1e9+7\)大概是把前面的区域以后再来探索吧Problem2.groupM