XOR SUM

#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cstring>

#include <queue>
#include <vector>
#include <set>
#include <map>

#include <iostream>
#include <iterator>
#include <string>
#include <algorithm>
#include <functional>
#include <utility>


#define MOD 1000000007
#define PI 3.1415926535897932384626433832795
#define INF LONG_MAX
#define X first
#define Y second
#define pb push_back
#define gc() getchar()

using namespace std;

inline void fastRead_int(int &x) {
    register int c = gc();
    x = 0;
    int neg = 0;
    for(; ((c<48 || c>57) && c != '-'); c = gc());
    if(c=='-') {
        neg = 1;
        c = gc();
    }
    for(; c>47 && c<58 ; c = gc()) {
        x = (x<<1) + (x<<3) + c - 48;
    }
    if(neg)
        x = -x;
}
struct node
{
    int value = -1;
    struct node *child[2] = {NULL};
};

node *head = NULL;

void insert_trie(int x)
{
    int base = 0x00200000;
    node *current = head;
    while(base)
    {
        int digit = base&x;
        digit = (digit == 0)?0:1;
        if(current->child[digit] == NULL)
            current->child[digit] = new node();
        current = current->child[digit];
        base>>=1;
    }
    current->value = x;
}

int query_trie(int x)
{
    node *current = head;
    int base = 0x00200000;
    while(base)
    {
        int digit = base&x;
        digit = (digit == 0)?0:1;
        if(current->child[abs(1-digit)] == NULL)
            current = current->child[digit];
        else
            current = current->child[abs(1-digit)];

        base>>=1;
    }
    return current->value;
}

int main(void)
{
    #ifndef ONLINE_JUDGE
        freopen("in.txt", "r", stdin);
    #endif


    int t,n,tmp;
    fastRead_int(t);
    while(t--)
    {
        fastRead_int(n);
        vector<int> arr(n);
        int maxx = 0;
        int maxIndx;
        head = new node();

        for(int i=0;i<n;i++)
            fastRead_int(arr[i]);

        tmp = 0;
        for(int i=0;i<n;i++)
        {
            tmp = tmp^arr[i];
            if(tmp >= maxx)
            {
                maxx = tmp;
                maxIndx = i;
            }
        }

        int ans = 0,qr;
        tmp = 0;
        insert_trie(0);
        for(int i=0;i<=maxIndx;i++)
        {
            tmp = tmp^arr[i];
            insert_trie(tmp);
            qr = query_trie(maxx);
            ans = ((qr^maxx)>ans)?(qr^maxx):ans;

        }
        printf("%d ", ans);
        arr.clear();
        head = NULL;
    }
    return 0;
}