Cod sursa(job #631751)
Utilizator | Stefan Lache StefanLache | Data | 9 noiembrie 2011 18:50:28 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 60 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.32 kb |
#include<stdio.h>
int n;
char prim[2000001];
int main()
{
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
int i,j,nr=0;
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;
}