Factorization (short, space separated) O(sqrt(n))

#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n;

    cin >> n;

    for (int i = 2; i <= sqrt(n); i++)
        while (n % i == 0)
        {
            cout << i << " ";

            n /= i;
        }

    if (n > 1)
        cout << n;

    return 0;
}