#include <iostream>
#include <cmath>
using namespace std;
typedef long long ll;

const int MAX_N = 60;
int N;
ll X, lb, ub;
int c[MAX_N];

int t;
void solve();

int main() {
    cin >> t;
    for (int tt = 0; tt < t; tt++)
        solve();
    return 0;
}

void solve() {
    cin >> N >> X;
    for (int i = 0; i < N; i++)
        cin >> c[i];
    lb = X, ub = X;
    for (int i = 0; i < N; i++) {
        ll tmp = (1LL << c[i]);
        if (X & tmp)
            continue;
        ll q = X / tmp;
        if (q % 2 == 0) {
            lb = min(lb, (q - 1) * tmp);
            ub = max(ub, (q + 1) * tmp);
        } else {
            if (X % tmp) {
                lb = min(lb, q * tmp);
                ub = max(ub, (q + 2) * tmp);
            }
        }
    }
    cout << min(abs(X - lb), abs(X - ub)) * 2 << endl;
}