Cod sursa(job #776947)

Utilizator EduardGeorgescuGeorgescu Eduard EduardGeorgescu Data 10 august 2012 17:59:20
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<iostream>
#include<fstream>
using namespace std;

ifstream in("ciur.in");
ofstream out("ciur.out");
	
int n,cnt;
char prim[2000005];

int main(){
	
int i,j;

in>>n;

for(i=2;i<=n;i++)
	prim[i]=1;

for(i=2;i<=n;i++)
	if(prim[i])
	{
		cnt++;
		for(j=i+i;j<=n;j=j+i)
			prim[j]=0;
	}
	
out<<cnt;

return 0;
}