#include <bits/stdc++.h>
using namespace std;
long long bitlength(long long n){
long long cnt=0;
while(n>0){
n>>=1;
cnt++;
}
return cnt;
}
int main() {
ios_base::sync_with_stdio(false);
long long t,i,j,n,k,ans,arr,len,m,val;
cin>>t;
while(t--){
cin>>n;
set<long long, greater<long long> > s[65],ss,w;
set<long long, greater<long long> >::iterator it;
w.clear();
for(i=0;i<65;i++)
s[i].clear();
for(i=0;i<n;i++)
{
cin>>arr;
len=bitlength(arr);
s[len].insert(arr);
}
for(i=64;i>=0;i--){
if(!s[i].empty()){
m=*(s[i].begin());
s[i].erase(m);
w.insert(m);
for(it=s[i].begin();it!=s[i].end();it++){
len=bitlength((*it)^m);
s[len].insert((*it)^m);
}
s[i].clear();
}
}
ans=0;
for(it=w.begin();it!=w.end();it++){
if(ans < (ans^(*it)))
ans^=(*it);
}
cout<<ans<<" ";
}
return 0;
}
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