Cod sursa(job #196650)

Utilizator StigmaSimina Pitur Stigma Data 27 iunie 2008 18:22:13
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <stdio.h>

int main(void)
{char a[2000001];
  int n,nr;
 int i,j;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);

scanf("%d",&n);

for (i=2; i<=n; i++) a[i]=0;

for (i=2; i<=n/2; i++)
if (a[i]==0)
 for (j=i+i; j<=n; j+=i)
   a[j]=1;

for (nr=0,i=2; i<=n; i++)
if (a[i]==0) nr++;

printf("%d\n",nr);

return(0);

}