1991C.cpp

#include <bits/stdc++.h>
#define pb push_back
#define fr first
#define sc second
#define mod 1000000007
#define mod2 998244353
#define len(x) x.size()
#define min3(a,b,c) min(a, min(b,c))
#define max3(a,b,c) max(a, max(b,c))
#define all(v) v.begin(), v.end()
#define rep(i,a,b) for(int i=a;i<b;i++)
#define per(i,a,b) for(int i=b-1,i>=a;i--)
#define int  long long
#define endl " \n"
using namespace std;
// Make sure to have 1 as 1ll for more than 32 bits
// Make sure to have seprate variables in nested loops
// Make sure minimum initialisation are large enough
// Make sure to use values before reinitilaising them such as count or sum
typedef unsigned long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pii> vpii;
typedef vector<vi> vvii;
typedef vector<string> vs;
int32_t main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int t;cin >> t;
    while(t--){
        int n;cin >> n;
        vector<int>v(n);
        for(int i = 0;i < n;i++) cin >> v[i];
        bool is = true;
        for(int i = 0;i < n - 1;i++){
            if(v[i] % 2 != v[i + 1]%2){
                is = false;
                break;
            }
        }
        if(!is) cout << -1 << endl;
        else{
            vector<int>op;
            for(int i = 0;i < 40;i++){
                int count = 0;
                int mx = 0;
                for(int j = 0;j < n;j++){
                    int temp = v[j];
                    if(v[j] == 0) count++;
                    int curr = 0;
                    while(temp/2){
                        temp /= 2;
                        curr++;
                    }
                    mx = max(mx,curr);
                }
                //cout << count << endl;
                int val = 1<<mx;
                if(count == n) break;
                else if(count > 0) val--;
                //cout << val << endl;
                for(int i = 0;i < n;i++) v[i] = abs(v[i] - val);
                //for(int i = 0;i < n;i++) cout << v[i] << " ";
                //cout << endl;
                op.push_back(val);
            }
            cout << op.size() << endl;
            for(int x : op) cout << x << " ";
            cout << endl;
        }
    }
}