Cod sursa(job #768302)
Utilizator | Data | 16 iulie 2012 16:14:17 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.34 kb |
#include <cstdio>
using namespace std;
int n, prim[2000001];
int main () {
freopen ("ciur.in", "r", stdin);
scanf ("%d", &n);
fclose (stdin);
int i, j, nr=0;
for (i=2; i<=n; ++i)
if (prim[i] == 0) {
++nr;
for (j=i+i; j<=n; j+=i)
prim[j] = 1;
}
freopen ("ciur.out", "w", stdout);
printf ("%d", nr);
fclose (stdout);
return 0;
}