#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define all(V) (V).begin(),(V).end()
typedef long long ll;

int main(void) {
	int t;
	cin >> t;

	vector<ll> ans;
	while (t > 0) {
		ll n, x;
		cin >> n >> x;

		vector<ll> c(n);
		rep(i, n) {
			cin >> c[i];
		}

		sort(all(c), greater<ll>());
		
		ll res = 0;
		rep(i, n) {

			if (!(x & (1LL << c[i]))) {
				ll big = (floor(x / powl(2, c[i])) + 1) * powl(2, c[i]);
				ll small = floor(x / powl(2, c[i])) * powl(2, c[i]) - 1;
				ll check = floor(x / powl(2, c[i]));

				if (check == 0 || abs(x - big) <= abs(x - small)) {
					res = 2 * abs(x - big);
					break;
				}
				else {
					res = 2 * abs(x - small);
					break;
				}
			}
		}
		ans.push_back(res);

		t--;
	}

	rep(i, ans.size()) {
		cout << ans[i] << endl;
	}

	return 0;
}