Counting ones

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n;
    cin >> n;
    vector<long long> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];

    int best = -1;
    long long x = 0, y = 0;

    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            long long p = a[i] * a[j];          
            int bits = __builtin_popcountll(p);
            if (bits > best) {
                best = bits;
                x = a[i];
                y = a[j];
            }
        }
    }

    cout << best << "\n";
    cout << x << " " << y << "\n";
}

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