Cod sursa(job #635083)

Utilizator johnny2008Diaconu Ion johnny2008 Data 18 noiembrie 2011 14:08:06
Problema Ciurul lui Eratosthenes Scor 60
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<fstream>
#include<iostream>
#include <string>
using namespace std;
char ok[2000001];
int main(){
	ifstream f("ciur.in");
	ofstream g("ciur.out");
	int n;
	f>>n;
	int i,ct=0,j;
	for(i=2;i<n;++i){
		
		if(ok[i]!='@'){
			++ct;
			for(j=i+i;j<=n;j=j+i){
				ok[j]='@';
			}
		}
		
	}
	
	g<<ct;
	return 0;
}