Cod sursa(job #158660)
| Utilizator |  Alex Vladescu alex3el_n2o |
Data | 13 martie 2008 19:15:58 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 0 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.32 kb |
#include <stdio.h>
short ciur[2000000001];
int main()
{
long n,i,j,k=0;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%ld",&n);
ciur[1]=1;
k=n;
for (i=2;i*i<=n;i++)
if (!ciur[i])
for (j=2;j*i<=n;j++)
{
if (!ciur[i*j]) k--;
ciur[i*j]=1;
}
printf("%ld\n",k-1);
return 0;
}