Cod sursa(job #156156)

Utilizator pikuAnca Miihai piku Data 12 martie 2008 13:14:29
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include<cstdio>
#define nmax 2000010

int n, v[nmax];

int main()
{
 int i, j, count=0;
 freopen("ciur.in", "r", stdin);
 freopen("ciur.out", "w", stdout);
 scanf("%d", &n);
 for(i = 2; i <= n; i++)
  if(!v[i])
   {
		count++;
		for(j = 2*i; j <= n; j += i)
			v[j] = 1;
   }
 printf("%d\n", count);
 return 0;
}