Cod sursa(job #1374634)

Utilizator RigonsRadu Molnar Rigons Data 5 martie 2015 10:20:22
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int i,j,v[2000000/2+1],n,nr;
int main()
{
    fin>>n;
    nr=1;
    for(i=3;i*2+1<=n;i+=2)
    {
        if(v[i]==0)
        {nr++;
        for(j=i+i+i;j*2+1<=n;j+=i*2+1)
            v[j]=1;}
    }
    fout<<nr;
    return 0;
}