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

void solve() {
  int N;
  long long X;
  cin >> N >> X;
  unordered_map<long long, long long> dp, ep;
  dp[0] = 0;
  for(int i = 0; i < N; i++) {
    int c;
    cin >> c;
    long long x = X & ((1LL << c) - 1);
    long long y = X & (1LL << c);
    if(y != 0) continue;
    // cout << "#" << endl;
    for(const auto [l, r] : dp) {
      long long l2 = - 1 - x;
      long long r2 = (1LL << c) - x;
      // cout << l << " " << r << " * " << l2 << " " << r2 << endl;
      {
        if(!ep.count(l)) ep[l] = max(r, r2);
        ep[l] = min(ep[l], max(r, r2));
      }
      if(X >= (1LL << c)) {
        if(!ep.count(min(l, l2))) ep[min(l, l2)] = r;
        ep[min(l, l2)] = min(ep[min(l, l2)], r);
      }
    }
    swap(dp, ep);
    ep.clear();
  }
  long long ans = 3LL << 60;
  for(const auto &[l, r] : dp) {
    ans = min(ans, 2 * (r - l));
    // cout << l << " " << r << endl;
  }
  cout << ans << "\n";
}

int main() {
  int T;
  cin >> T;
  while(T--) solve();
}