```cpp
#include <bits/stdc++.h>
#define int long long
using namespace std;
int r;
//inline void outs(int a,int b)
//{ cout<<"( x , y ) = ( "<<a<<" , "<<b<<" )"<<endl;
//}
inline int gcd(int a,int b)
{ while(b^=a^=b^=a%=b);
return a;
}
inline int cal(int k)
{ int d=r/k,ret=0;
for(int m=1;m*m<=k;++m)
{ int n=sqrt(k-m*m);
if(n*n+m*m!=k) continue;
if(gcd(n,m)!=1) continue;
int x=d*(m*m-n*n)/2;
int y=d*n*m;
if(x>0&&y>0&&x*x+y*y==r*r/4) /*outs(x,y),*/++ret;
}
return ret;
}
signed main()
{ cin>>r,r<<=1;
int ans=0;
for(int i=1;i*i<=r;++i)
if(r%i==0)
{ ans+=cal(i);
if(i!=r/i) ans+=cal(r/i);
}
cout<<(ans+1)*4<<endl;
return 0;
}
```
by RP_INT_MAX @ 2023-09-23 23:04:04
爆 ll 了。此贴结。
by RP_INT_MAX @ 2023-09-23 23:30:29