Cod sursa(job #156367)

Utilizator pandaemonAndrei Popescu pandaemon Data 12 martie 2008 14:58:33
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>

char notprim[2000001];

main()
{freopen("ciur.in","r",stdin);
 freopen("ciur.out","w",stdout);

 long n,i,j;  scanf("%ld",&n);

 for(i=2;i<=n/2;i++)
 if(notprim[i]==0)
 for(j=i+i;j<=n;j+=i) notprim[j]=1;

 long contor=0;

 for(i=2;i<=n;i++)
 if(notprim[i]==0) contor++;

 printf("%ld\n",contor);}