来自朝鲜的题解

#include <bits/stdc++.h> using namespace std; int a[605]; int sum=0; int main(){ freopen("frac.in","r",stdin); freopen("frac.out","w",stdout); int n; cin>>n; for(int i=0;i<=n-1;i++){ cin>>a[i]; } for(int i=0;i<=n-1;i++){ for(int j=0;j<=n;j++){ if(__gcd(a[i],a[j])==1&&i!=j){ sum++; } } } cout<<sum/2; return 0; }