1601A - Array Elimination - CodeForces Solution

#include <bits/stdc++.h>
// #define int long long
#define ff first
#define ss second
#define ll long long
#define ld long double
#define pb push_back
#define vi vector<int>
#define pii pair<int, int>
#define sws cin.tie(0)->sync_with_stdio(false);
#define endl '\n'

using namespace std;

const int N = 3e6+10;
const ll MOD = 998244353;
const int INF = 0x3f3f3f3f;
const ll LLINF = 0x3f3f3f3f3f3f3f3f;
const ld EPS = 1e-6;
const ld PI = acos(-1); 

// #pragma GCC target("popcnt")

// End Template //

vector<int> div(int x) {
    vector<int> ans;
    for (ll i=1;i*i<=x;i++) {
        if (x % i == 0) {
            ans.pb(i);
            if (i*i != x) ans.pb(x/i);
        }
    }
        
    sort(ans.begin(), ans.end());
    return ans;
}

int32_t main()
{sws;
        
    int t; cin >> t;
    while (t--) {
        int n; cin >> n;
        vector<ll> a(n), f(31, 0);
        for (int i=0;i<n;i++) {
            cin >> a[i];
            for (int j=0;j<=30;j++) {
                f[j] += !!(a[i] & (1LL << j));
            }
        }

        int g = -1;
        for (int j=0;j<=30;j++) {
            if (f[j] == 0) continue;
            if (g == -1) g = f[j];
            g = gcd(g, f[j]);
        }

        if (g == -1) {
            for (int i=1;i<=n;i++) {
                cout << i << " ";
            }
            cout << endl;
        } else {
            vector<int> d = div(g);

            for (auto di: d) {
                cout << di << " ";
            }
            cout << endl;
        }

    }

    
    return 0;
}