Cod sursa(job #1554314)

Utilizator luca_robertaLuca Roberta luca_roberta Data 21 decembrie 2015 11:50:59
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.45 kb
Raporteaza aceasta sursa 
#include <cstdio>

using namespace std;

int main()
{
    int N,nr=0,i,j;
    bool p[2000001];
    freopen("ciur.in","r",stdin);
    freopen("ciur.out","w",stdout);
    scanf("%d",&N);
    for(int i=2;i<=N;i++)
        p[i]=1;
    for(i=2;i<=N;i++)
        if(p[i]==1)
            for(j=i;j<=N/i;j++)
                p[i*j]=0;
    for(int i=2;i<=N;i++)
            if(p[i])
                nr++;
    printf("%d", nr);
    return 0;
}