Cod sursa(job #275497)

Utilizator Ionut_infoNicoara Ionut Ionut_info Data 10 martie 2009 15:09:27
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>
long int n,i,j,nr;
FILE *in=fopen("ciur.in","r");
FILE *out=fopen("ciur.in","w");
int main()
{
char p[2000001];
fscanf(in,"%ld",&n);
for(i=1;i<=n;i++) p[i]=0;nr=1;
for(i=3;i<=n;i+=2)
	{
	if(p[i]==0)
		{
		nr++;
		for(j=i+i+i;j<=n;j+=i*2)
			{
			p[j]=1;
			}
		}
	}
fprintf(out,"%ld",nr);
return 0;
}