#include <bits/stdc++.h>
using namespace std;
#include <atcoder/modint>
using namespace atcoder;
#ifdef DEFINED_ONLY_IN_LOCAL
#include <dump.hpp>
#define dump(...) cpp_dump(__VA_ARGS__)
#else
#undef dump
#define dump(...)
#endif
#define rep1(i, a) for (int i = 0; i < (int)(a); i++)
#define rep2(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep3(i, a, b, c) for (int i = (int)(a); i < (int)(b); i += (int)(c))
#define overloadRep(a, b, c, d, e, ...) e
#define rep(...) overloadRep(__VA_ARGS__, rep3, rep2, rep1)(__VA_ARGS__)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
using ll = long long;
using ull = unsigned long long;
const int inf = 1e9;
const ll INF = 1e18;
const int dx[4] = {0, 1, 0, -1};
const int dy[4] = {1, 0, -1, 0};
const int ddx[8] = {1, 0, -1, 0, 1, -1, 1, -1};
const int ddy[8] = {0, 1, 0, -1, 1, -1, -1, 1};
struct cincout {cincout() {ios_base::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(15);}} init;
template <class T> inline bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
template <class T> inline bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template <class T1, class T2> istream& operator>>(istream& is, pair<T1, T2>& p) {is >> p.first >> p.second; return is;}
template <class T1, class T2> ostream& operator<<(ostream& os, const pair<T1, T2>& p) {os << p.first << " " << p.second << '\n'; return os;}
template <class T> istream& operator>>(istream& is, vector<T>& v) {for (T& in : v) {is >> in;} return is;}
template <class T> ostream& operator<<(ostream& os, const vector<T>& v) {rep(i, (int)v.size()) {os << v[i] << " \n"[i + 1 == (int)v.size()];} return os;}
template <class T> istream& operator>>(istream& is, vector<vector<T>>& vv) {for (vector<T>& v : vv) {is >> v;} return is;}
template <class T> ostream& operator<<(ostream& os, vector<vector<T>>& vv) {for (vector<T>& v : vv) {os << v;} return os;}
inline bool bit(ll x, int p) {return (x >> p) & 1;}
inline bool out(int ni, int nj, int h, int w) {return (ni < 0 or ni >= h or nj < 0 or nj >= w);}
inline int pc(ll x) {return __builtin_popcountll(x);}
template <class T> inline T max(vector<T> x) {return *max_element(x.begin(), x.end());}
template <class T> inline T min(vector<T> x) {return *min_element(x.begin(), x.end());}
template <class T> inline T sum(vector<T> x) {return reduce(x.begin(), x.end());}
using P = pair<int, int>;
using T = tuple<int, int, int>;
void solve() {
    int n;
    ll x;
    cin >> n >> x;
    vector<ll> c(n);
    cin >> c;
    rep(i, n) c[i] = 1LL << c[i];
    vector<bool> on(n);
    rep(i, n) {
        on[i] = (x / c[i]) & 1;
    }
    bool f = true;
    ll lm = INF, rm = INF;
    for (int i = n - 1; i >= 0; i--) if (!on[i]) {
        ll m = x % c[i];
        ll l = (x > c[i] ? m + 1 : INF);
        ll r = c[i] - m;
        if (f) {
            f = false;
            ll ans = min(l * 2, r * 2);
            cout << ans << endl;
            return;
        }
    }
    cout << 0 << endl;
}
int main() {
    int t;
    cin >> t;
    while (t--) solve();
    return 0;
}