Cod sursa(job #1781799)
Utilizator | Data | 17 octombrie 2016 14:45:28 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include<cstdio>
char v[2000001];
int main()
{
int n,s;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%d",&n);
v[1]=1;
s=0;
for(int i=2;i*i<=n;i++)
{
if(v[i]==0)
{
for(int j=i+i;j<=n;j+=i)
{
if(v[j]==0)
s++;
v[j]=1;
}
}
}
/*s=0;
for(int i=1;i<=n;i++)
{
if(v[i]==0)
s++;
}*/
printf("%d",n-s-1);
return 0;
}