Cod sursa(job #1881844)

Utilizator pimao2004Lupu Stefan Dragos pimao2004 Data 16 februarie 2017 19:40:18
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
#include <fstream>

using namespace std;
ifstream in ("fractii.in");
ofstream out ("fractii.out");
int v[1000002];
int main()
{
    int n;
    in>>n;
    long long s=1;
    int i,j;
    for(i=2;i<=n;i++)
    {
        v[i]=v[i]+i-1;
        for(j=i*2;j<=n;j+=i)
        v[j]-=v[i];
        s=s+v[i]*2;
    }
    out<<s;
    return 0;
}