Cod sursa(job #461776)
Utilizator | Data | 8 iunie 2010 16:34:47 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.32 kb |
#include<stdio.h>
bool c[2000001];
int i,j,k,n;
int main()
{
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%d",&n);
c[1]=true;
for (i=2;i*i<=n;++i)
if (!c[i])
for (j=i*i;j<=n;j+=i)
c[j]=true;
for (i=2;i<=n;++i)
if (!c[i])
++k;
printf("%d",k);
return 0;
}