Cod sursa(job #690916)

Utilizator sk8ervinMaftei Ervin sk8ervin Data 26 februarie 2012 00:57:00
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
int main()
{
long long n,d,i,j,k,v[1000001];
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
k=0;
for(i=1;i<=n;i++)
v[i]=i;
for(i=2;i<=n;i++)
{
    if(v[i]==i)
    {
        for(j=i;j<=n;j+=i)
        v[j]=v[j]*(i-1)/i;
    }
}

for(i=2;i<=n;i++)
k+=v[i];

g<<2*k+1;

return 0;
}