Cod sursa(job #1369661)

Utilizator octav1234Pocola Tudor Octavian octav1234 Data 3 martie 2015 10:30:17
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.41 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
ifstream fi("ciur.in");
ofstream fo("ciur.out");
int N;
bool P[2000002];
int REZ;
int main()
{
    fi>>N;
    P[1]=true;
    for(int i=2;i<=N;i++)
        if(!P[i])
            for(int d=i+i;d<=N;d+=i)
                P[d]=true;
    for(int i=1;i<=N;i++)
        if(!P[i])
            REZ++;
    fo<<REZ<<'\n';
    fi.close();
    fo.close();
    return 0;
}