Cod sursa(job #1693919)

Utilizator bassista02Dorela Marina bassista02 Data 24 aprilie 2016 11:10:05
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
int n,m,a[2000001];
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int main(){
fin>>n;
for(int i=2;i<=n;i++)a[i]=i;
for(int i=2;i*i<=n;i++)
    if(a[i])
        for(int j=i*2;j<=n;j++)
            if(a[j]%a[i]==0) a[j]=0;
for (int i=2;i<=n;i++) if(a[i]) m++;
fout<<m<<'\n';
return 0;

}