Cod sursa(job #206763)
Utilizator | Data | 9 septembrie 2008 13:51:16 | |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.35 kb |
#include <fstream>
using namespace std;
ofstream ofis("fractii.out");
ifstream ifis("fractii.in");
int main()
{
long n,i,j,v[1000001];
long long nr;
for (i=2; i<=n; i++)
v[i]=i-1;
for (i=2; i<=n; i++)
{
for (j=2*i; j<=n; j+=i)
v[j]-=v[i];
nr+=v[i];
}
ofis<<2*nr+1;
return 0;
}