Solution -「洛谷 P6156」简单题
DescriptionLink.求 $\sum\limits_{i=1}^n\sum\limits_{j=1}^n(i+j)^kf(\gcd(i,j))\gcd(i,j)$。Solution$$...
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.