https://oj.neu.edu.cn/problem/1460 思路:若n=(p1^a1)*(p2^a2)...(pn^an),则f(n,0)=a1*a2*...*an,显然f(n,0)是积性函数,对于f(x,y)可以看出他是f(x,y-1)与自身进行狄利克雷卷积得到的结果,所以f(x,y)也是积性函数.因此,只要对n质因子分解,然后与预理出次方的dp值即可.注意积性函数的概念中a,b必须互质! #include<bits/stdc++.h> #define int long long…
Discription Bash got tired on his journey to become the greatest Pokemon master. So he decides to take a break and play with functions. Bash defines a function f0(n), which denotes the number of ways of factoring n into two factors p and q such that …