Cod sursa(job #1607522)

Utilizator superstar1998Moldoveanu Vlad superstar1998 Data 21 februarie 2016 12:33:07
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>
using namespace std;
bool npr[2000001];
int n,cnt=1,i,j;
ifstream f("ciur.in");
ofstream g("ciur.out");
int main()
{
    f>>n;
    for(i=3;i<=n;i+=2)
        if(!npr[i])
        {
            cnt++;
            for(j=3*i;j<=n;j+=i*2)
                npr[j]=true;
        }
    g<<cnt;
    return 0;
}