Cod sursa(job #801180)
Utilizator | Data | 23 octombrie 2012 17:57:03 | |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.29 kb |
#include <fstream>
using namespace std;
int s[1000001];
int main()
{
int n,i,j,r;
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
for(i=2;i<=n;i++)
s[i]=i-1;
for(i=2;i<=n;i++)
{
r+=s[i];
for(j=i+i;j<=n;j=j+i)
s[j]-=s[i];
}
r+=1+r;
g<<r;
return 0;
}