Counting ones

#include <bits/stdc++.h>

using namespace std;

int main() {

    // ios_base::sync_with_stdio(0);

    int n;
    cin >> n;

    vector<uint64_t> x(n);
    for (int k = 0; k < n; k++)
        cin >> x[k];
    
    int a = 0, b = 0;
    int max = -1;

    for (int i = 0; i < n; i++) {
        for (int j = i+1; j < n; j++) {
            uint64_t r = x[i] * x[j];
            uint32_t *p = (uint32_t *) (&r);
            int count = __builtin_popcount(*p) +
                        __builtin_popcount(*(p+1));
            if (count > max) {
                max = count;
                a = i;
                b = j;
            }
        }
    }

    cout << max << "\n" << x[a] << " " << x[b] << "\n";
    return 0;

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED