Cod sursa(job #635207)

Utilizator johnny2008Diaconu Ion johnny2008 Data 18 noiembrie 2011 19:21:47
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.32 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;j*i<n;++j){
				ok[i*j]='@';
			}
		}
	}
	g<<ct;
	return 0;
}