Cod sursa(job #2305393)

Utilizator Lsilviu02Linca Silviu Lsilviu02 Data 20 decembrie 2018 08:56:06
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.57 kb
#include <iostream>
int MAXSIZE = 100000000/2/8+1;
using namespace std;
char p[1000];
int n,i,j,nr=1;
int main()
{
    cin>>n;
    for (i = 1; ((i * i) << 1) + (i << 1) <= n; i += 1)
    {
        if ((p[i >> 3] & (1 << (i & 7))) == 0)
        {
            for (j = ((i * i) << 1) + (i << 1); (j << 1) + 1 <= n; j += (i << 1) + 1)
            {
                p[j >> 3] |= (1 << (j & 7));
            }
        }
    }
    for (i = 1; 2 * i + 1 <= n; ++i)
        if ((p[i >> 3] & (1 << (i & 7))) == 0)
            nr++;
        cout<<nr<<" ";
    return 0;
}