Cod sursa(job #2383590)

Utilizator LORDENVraja Luca LORDEN Data 19 martie 2019 17:57:46
Problema Ciurul lui Eratosthenes Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.41 kb
#include <fstream>

using namespace std;
int n,i,v[1500000],j,nr;
int main()
{
    ifstream fin("ciur.in");
    ofstream fout("ciur.out");
    fin>>n;
    for(i=2; i*i<=n; i++)
    {
        if(v[i]==0)
        {
            for(j=i*i; j<=n; j=j+i)
                v[j]=1;
        }
    }
    nr=0;
    for(i=2; i<=n; i++)
        if(v[i]==0)
            nr++;
    fout<<nr;
    return 0;
}