Cod sursa(job #2427518)

Utilizator PrekzursilAndrei Visalon Prekzursil Data 31 mai 2019 23:06:11
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <cstdio>
bool ciur[2000001];
int main()
{
    freopen("ciur.in","r",stdin);
    freopen("ciur.out","w",stdout);
    int n,i,j,k=0;
    scanf("%d",&n);
    ciur[0]=ciur[1]=1;
    for(i=2;i*i<=n;i++)
		if(ciur[i]==0)
			for(j=i;j*i<=n;j++)
				ciur[i*j]=1;
	for(i=2;i<=n;i++)
		if(ciur[i]==0)
			k++;
	printf("%d",k);
    return 0;
}