Cod sursa(job #539582)

Utilizator flslatina95Marin Florin flslatina95 Data 23 februarie 2011 08:39:03
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include<fstream.h>
ifstream fin("ciur.in");
ofstream fout("ciur.out");
unsigned char a[2000000];
long n,i,j,nr;
int main()
{
    a[0]=a[1]=1;
	fin>>n;
	for(i=2;i*i<=n;i++)
		if(a[i]==0)
			for(j=2*i;j<=n;j=j+i)
			   a[j]=1;

			for(i=2;i<=n;i++)			
				if(a[i]==0)
					nr++;
	fout<<nr;
return 0;
}