Cod sursa(job #830787)

Utilizator dumitrascumihaiDumitrascu Mihai dumitrascumihai Data 7 decembrie 2012 18:23:29
Problema Fractii Scor 30
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
int main()
{
    int n,a[1000001],i,j,s=0;
	ifstream f("fractii.in");
	ofstream g("fractii.out");
	f>>n;
	for(i=2;i<=n;i++)
    {
        a[i]=i-1;
    }

    for(i=2;i<=n;i++)
    {
        s+=a[i];
        for(j=i+i;j<=n;j+=i)
        {
            a[j]-=a[i];
        }
    }

    g<<2*s+1;
}