Cod sursa(job #1312241)

Utilizator Alex1199Alex Bercea Alex1199 Data 9 ianuarie 2015 00:41:17
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
bool a[2000001];
int64_t i, j, n, m=1;;
int main()
{
   f>>n;
     for(i=3;i*i<=n;i++)
        for(j=i*i;j<=n;j=j+2*i)
          a[j]=true;
   for(i=3;i<=n;i+=2)
        if(!a[i]) m++;
        g<<m;
    return 0;
}