Cod sursa(job #296714)
Utilizator | FMI - vacaroiu andrei andreiv | Data | 5 aprilie 2009 01:29:47 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.52 kb |
#include <stdio.h>
int N, cnt;
char prim[2000005];
int main()
{
int i, j;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%d",&N);
for (i = 2; i <= N;i++)
prim[i] = 1;
for (i = 2; i <= N; i++)
if (prim[i])
{
cnt++;
for (j = i+i; j <= N; j += i)
prim[j] = 0;
}
printf("%d",cnt);
return 0;
}