Cod sursa(job #548905)
Utilizator | Dumitraiche Marius-Alexandru Alexandru13 | Data | 7 martie 2011 22:01:51 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.3 kb |
#include<fstream.h>
ifstream f("ciur.in");
ofstream g("ciur.out");
long long n,i,x,j;
char a[2000009];
int main()
{
f>>n;
for(i=1;i<=n;i++)
a[i]=1;
int x=0;
for(i=2;i<=n;i++)
if(a[i]==1)
{
for(j=i;j<=n;j+=i)
a[j]=0;
x++;
}
g<<x;
f.close();
g.close();
return 0;
}