Cod sursa(job #2254378)

Utilizator dinugaftonGafton Dinu dinugafton Data 5 octombrie 2018 10:49:47
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.3 kb
Raporteaza aceasta sursa 
#include<bits/stdc++.h>
using namespace std;
bool a[2000010];
int main(){
	ifstream cin("ciur.in");
	ofstream cout("ciur.out");
	long long n,k=0;
	cin>>n;
	for(long long i=2;i<=n;i++){
		if(a[i]==0){
			k++;
		for(long long j=i*i;j<=n+1;j+=i){
			a[j]=1;
		}
	}
	}
	cout<<k;
	return 0;
}