#include <bits/stdc++.h>
using namespace std;

#define ll long long

const int N = 200005;

ll a[N], K;
int must[60], n;

void sc() {
    memset(must, -1, sizeof(must));
    scanf("%d%lld", &n, &K);
    for (int i = 1; i <= n; i++) {
        scanf("%lld", &a[i]);
    }
    for (int i = 1; i < n; i++) {
        ll t = a[i] ^ a[i + 1];
        if (t == 0) continue;
        int pos = 63 - __builtin_clzll(t);
        int p = (a[i] >> pos & 1 ? 1 : 0);
        if (must[pos] != -1 && must[pos] != p) {
            puts("0");
            return;
        }
        must[pos] = p;
    }
    
    ll ans = 0;
    for (int b = 59; b >= 0; b--) {
        if (K >> b & 1) {
            // 0 free
            if (must[b] != 1) {
                ll power = 1;
                for (int a = b - 1; a >= 0; a--)
                    if (must[a] == -1)
                        power *= 2;
                ans += power;
            }
            if (must[b] == 0) break;
        } else {
            if (must[b] == 1) break;
        }
    }
    printf("%lld\n", ans);
}

int main() {
    int T; scanf("%d", &T);
    while (T--) sc();
    return 0;
}