Cod sursa(job #1892640)

Utilizator anamaria41Raicu Ana anamaria41 Data 25 februarie 2017 10:29:35
Problema Fractii Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.32 kb
Raporteaza aceasta sursa 
#include <fstream>

using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
long long n,i,j,s,v[1000050];
int main()
{
   f>>n;
   for(i=2;i<=n;i++)v[i]=i-1;
   for(i=2;i<=n;i++)
   {
       s+=v[i];
       for(j=2*i;j<=n;j+=i)
        v[j]=v[j]-v[i];
   }
   g<<2*s+1;
    return 0;
}