Cod sursa(job #490721)
| Utilizator |  George 6301263 |
Data | 7 octombrie 2010 17:14:12 |
|---|---|---|---|
| Problema | Fractii | Scor | 100 |
| Compilator | cpp | Status | done |
| Runda | Arhiva de probleme | Marime | 0.31 kb |
#include<fstream>
using namespace std;
int main()
{
ifstream f("fractii.in");
ofstream g("fractii.out");
long long q,n,h[1000001],i,t=0;
f>>n;
for(i=2;i<=n;i++)
h[i]=i-1;
for(i=2;i<=n;i++)
{
t+=h[i];
for(q=2*i;q<=n;q+=i)
h[q]-=h[i];
}
g<<t*2+1;
f.close();
g.close();
return 0;
}