Solution -「LOCAL 28731」「重庆市 2021 中学友谊赛」Rainyrabbit 爱求和
DescriptionLink.$\operatorname{Rainyrabbit}$ 是一个数学极好的萌妹子,近期他发现了一个可爱的函数:$$
f(n,m,k)=\sum_{d=1}^n d...
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.