Cod sursa(job #809641)

Utilizator petiVass Peter peti Data 8 noiembrie 2012 19:22:20
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;


int main(){
	ifstream ifs("ciur.in");
	ofstream ofs("ciur.out");
	int N;
	long long int nr=0;
	ifs>>N;
	vector<char> v(N+1,0);
	
	for(int i=3;i<=N;i+=2){
		if(v[i]==0){
			nr++;
			for(int j=i+i;j<=N;j+=i){
				v[j]=1;
			}
		}
	}
	ofs<<nr+1;
	return 0;
}