Cod sursa(job #790601)

Utilizator buntomToma Alexandru buntom Data 21 septembrie 2012 21:30:36
Problema Fractii Scor 50
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.31 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
long n,i,j,a[100000];
long long s;
int main()
{ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
for(i=1;i<=n;i++)
    a[i]=i-1;
for(i=2;i<=n;i++)
    for(j=2;i*j<=n;j++)
        a[i*j]-=a[i];
s=1;
for(i=1;i<=n;i++)
    s+=2*a[i];
g<<s;
return 0;
}