Cod sursa(job #809507)

Utilizator mitrutstrutMitrea Andrei Ionut mitrutstrut Data 8 noiembrie 2012 16:50:55
Problema Aliens Scor 0
Compilator c Status done
Runda Arhiva de probleme Marime 0.34 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
int n,w[10000000];
int i,j,s=0;
int main()
{   f>>n;
    for(i=2;i<=n;++i) w[i]=i-1;
    for(i=2;i<=n;++i)
        {   s=s+w[i];
            for(j=i+i;j<=n;j+=i) w[j]=w[j]-w[i];
        }
    g<<2*s+1<<'\n';
    g.close();
    return 0
}