Cod sursa(job #631759)
Utilizator | Data | 9 noiembrie 2011 18:57:13 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 50 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.32 kb |
#include<stdio.h>
int n,nr;
char prim[2000001];
int main()
{
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
int i,j;
scanf("%d",&n);
for(i=2;i<=n;++i)
prim[i]=1;
for(i=2;i<=n;++i)
if(prim[i])
{
++nr;
for(j=i+i;j<=n;j+=i)
prim[j]=0;
}
printf("%d ",nr);
return 0;
}