Cod sursa(job #504839)

Utilizator Dumitru_GeorgeDumitru George Cristian Dumitru_George Data 28 noiembrie 2010 23:17:09
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<iostream>
#include<fstream>
#include<math.h>
#define N 2000001
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
long long i,j,n,t,v[N];

int main()
{
f>>n;
for(i=2;i<=n;i++)
	if(v[i]==0)
		for(j=2;i*j<=n;j++)v[i*j]=1;

for(i=2;i<=n;i++)
	if(v[i]==0)t++;

g<<t;
	f.close();
	g.close();
	return 0;
}