Cod sursa(job #1860921)

Utilizator XIIICristian Boicu XIII Data 28 ianuarie 2017 14:40:18
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.32 kb
Raporteaza aceasta sursa 
#include <bits/stdc++.h>
using namespace std;
long long i,j,n,k;
bool a[20000002];
int main(){
	ifstream cin("ciur.in");
	ofstream cout("ciur.out");
	cin>>n;
	for (i=2;i<=n;i++)
		if  (a[i]==false)
		for (j=2;j<=n/i;j++){
		 a[i*j]=true;	 
	
	}for (i=2;i<=n;i++)
	if (a[i]==false) k++;
	cout<<k;
	return 0;
	
}