Cod sursa(job #1732220)

Utilizator Kln1000Ciobanu Bogdan Kln1000 Data 21 iulie 2016 10:31:59
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream f ("ciur.in");
ofstream t ("ciur.out");

int n,v[2000001];

void sift(int x){
for (int i=x*x;i<=n;i+=x)
v[i]=1;
}

int magic(){int s=0;
for (int i=2;i<=n;++i){
if (!v[i])
++s;
sift(i);}
return s;
}

int main()
{f>>n;
t<<magic();
return 0;
}