Cod sursa(job #2564563)

Utilizator RaduZevriRadu Zevri RaduZevri Data 1 martie 2020 23:11:43
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>

#define max 2000001

int p[max];
int n;

int main(){
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);

	scanf("%d",&n);
	p[1] = 1;
	for(int i=2;i<=n;i++){
		if(p[i]) continue;
		int j = 2;
		while(j<=n/i+1){
			p[i*j]=1;
			j++;
		}
	}
	int c=0;
	for(int i=1;i<=n;i++) if(!p[i]) c++;
	printf("%d",c);
}