Cod sursa(job #501407)
Utilizator | Laura S buburuza | Data | 14 noiembrie 2010 21:31:57 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.44 kb |
#include <algorithm>
#include <bitset>
using namespace std;
#define dim 2000001
//unsigned
//unsigned char v[dim];
bitset <dim> v;
int main()
{
int n, f=1;
freopen ("ciur.in","r",stdin) ;
freopen ("ciur.out","w",stdout) ;
scanf("%d", &n);
for(int i=2;i<n;++i)
{
++i;
if(!v[i])
{
++f;
for(int j=i;j<=n/i;++j)
{
v[j*i]=1;
++j;
}
}
}
printf("%d", f);
return 0;
}