Cod sursa(job #1610809)

Utilizator ipus1Stefan Enescu ipus1 Data 23 februarie 2016 19:02:51
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<cstdio>
char ciur[2000001];
int main ()
{freopen ("ciur.in","r",stdin);
freopen ("ciur.out","w",stdout);
int n,i,j,s=0;
scanf("%d",&n);
for(i=2;i<=n/2;i++)
    ciur[i*2]=1;
for(i=3;i*i<=n;i+=2)
    for(j=i;i*j<=n;j+=2)
        ciur[i*j]=1;
for(i=2;i<=n;i++)
    if(ciur[i]==0)
        s++;
printf("%d",s);
return 0;
}