Cod sursa(job #107676)
Utilizator | Paicu Alexandru rethos | Data | 20 noiembrie 2007 10:04:50 |
---|---|---|---|
Problema | Fractii | Scor | 10 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.46 kb |
#include <fstream.h>
int p[1000];
long long funct(long long x)
{ long long i,j,n;
for (i=1;i<=x;i++) p[i]=0;
for (i=2;i<x;i++)
if (x%i==0&&p[i]==0)
{ for (j=i;j<=x;j=j+i)
p[j]=1;
}
n=0;
for (i=1;i<x;i++) if (p[i]==0) n++;
return n;
}
int main()
{ long long n,i,nr=0;
ifstream f("fractii.in");
f>>n;
f.close();
for (i=2;i<=n;i++)
nr+=funct(i)*2;
nr++;
ofstream g("fractii.out");
g<<nr;
g.close();
return 0;
}