Cod sursa(job #913309)
Utilizator | Data | 13 martie 2013 11:47:14 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include <cstdio>
#define N 2000000
using namespace std;
bool a[N];
int p,j,q,n,nr;
int main()
{
ifstream ("ciur.in","r",stdin);
ofstream ("ciur.out","w",stdout);
scanf("%d",&n);
for(int i=2;i<=n;i++)
{
if(a[i]==0)
{
nr++;
j=i;
q=i;
}
for(;j<=n;j+=q)
a[j]=1;
}
printf("%d\n",nr);
return 0;
}