Cod sursa(job #898168)

Utilizator antonio.salaruAntonio Salaru antonio.salaru Data 28 februarie 2013 08:27:05
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.29 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");	
int v[2000001],n,a,b,nr;
int main()
{f>>n;
for(a=2;a<=n;a++)
	if(v[a]==0)
		for(b=a+a;b<=n;b+=a)
			v[b]=1;  
for(a=2;a<=n;a++)
	if(v[a]==0)  
        nr++;
g<<nr<<'\n';  
g.close();	
return 0;
}