Cod sursa(job #1855725)

Utilizator Constantin.Dragancea Constantin Constantin. Data 23 ianuarie 2017 21:20:56
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include <bits/stdc++.h>
using namespace std;

int n,i,j,k;
bool a[2000100];

int main(){
    ifstream cin ("ciur.in");
    ofstream cout ("ciur.out");
    cin>>n;
    for (i=2; i<=n; i++){
        if (!a[i]){
            k++;
            for (j=i+i; j<=n; j+=i) a[j]=true;
        }
    }
    cout<<k;
    return 0;
}