Cod sursa(job #371191)

Utilizator avram_florinavram florin constantin avram_florin Data 4 decembrie 2009 01:10:21
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<cstdio>
#define Maxn 2000005
using namespace std;
int i,j,n,nr;
char v[Maxn];
int main ()
{
	freopen("ciur.in" , "r" , stdin);
	freopen("ciur.out" , "w" ,stdout);
	scanf("%d" , &n);
	nr=0;
	for(i=2;i<=n;i++)
		if(!v[i])
			{
				nr++;
				for(j=i+i;j<=n;j+=i)
					v[j]=1;
			}
	printf("%d" , nr);
	return 0;
}