Counting ones

#include <bits/stdc++.h>

using namespace std;
#define int long long
#define vout(x) for(int i=0;i<(long long)x.size();i++) printf("%lld ",x[i]);
#define REP(i,a,b) for (int i = a; i < b; i++)

// g++ <filename>.cpp -g -Wall -Wextra -DDEBUG -o <executable>

// copied from: https://codeforces.com/blog/entry/79024
// === Debug macro starts here ===

int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) {++recur_depth; auto x_=x; --recur_depth; cerr<<string(recur_depth, '\t')<<"\e[91m"<<__func__<<":"<<__LINE__<<"\t"<<#x<<" = "<<x_<<"\e[39m"<<endl;}
#else
#define dbg(x)
#endif
template<typename Ostream, typename Cont>
typename enable_if<is_same<Ostream,ostream>::value, Ostream&>::type operator<<(Ostream& os,  const Cont& v){
	os<<"[";
	for(auto& x:v){os<<x<<", ";}
	return os<<"]";
}
template<typename Ostream, typename ...Ts>
Ostream& operator<<(Ostream& os,  const pair<Ts...>& p){
	return os<<"{"<<p.first<<", "<<p.second<<"}";
}

// === Debug macro ends here ===

signed main() {
    
    int n;
    cin >> n;
    vector<int> numbers(n);
    
    REP(i, 0, n) {
        cin >> numbers[i];
    }

    sort(numbers.begin(), numbers.end());

    int max_ones = 0;   
    int num1 = 0;
    int num2 = 0;
    
    REP(i, 0, n) {
        REP(j, 0, n) {
            
            if (i == j) continue;

            int prod = numbers[i] * numbers[j];
            int ones_count = __builtin_popcountll(prod);
            
            if (ones_count > max_ones) {
                max_ones = ones_count;
                num1 = numbers[i];
                num2 = numbers[j];
            }
        }
    }
    
    cout << max_ones << "\n";
    cout << num1 << " " << num2 << "\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