Cod sursa(job #156024)

Utilizator rethosPaicu Alexandru rethos Data 12 martie 2008 12:15:18
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <stdio.h>
#define NM 2000001
int main()
{ long n,nr;
  char p[NM];
  freopen("ciur.in","rt",stdin);
  freopen("ciur.out","wt",stdout);
  scanf("%ld",&n);
  nr=0;int i,j;
  for(i=2;i<=n;i++) p[i]=1;
  for(i=2;i<=n;i++)
	if (p[i]==1)
		{ nr++;
		  for (j=2*i;j<=n;j+=i) p[j]=0;
		}
  printf("%ld",nr);
  fcloseall();
  return 0;
}