1270C - Make Good - CodeForces Solution

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main()
{
 ll t;
 cin>>t;
 while (t--)
 {
   ll n;
   cin>>n;
   vector<ll>vec;
   ll sum=0;
   ll pxor=0;
   for (ll i = 0; i < n; i++)
   {
     ll x;
     cin>>x;
     sum+=x;
     pxor=(pxor^x);
   }

   cout<<3<<endl;
   cout<<pxor<<" "<<(pxor+sum)<<" "<<0<<endl;
   
 }
 
 return 0;
}