#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
int main() {
  cin.tie(0); cout.tie(0);
  ios::sync_with_stdio(false);
  int T;
  cin >> T;
  while(T--) {
    int N;
    long long X;
    cin >> N >> X;
    vector<int> c(60);
    vector<long long> L, R;
    for(int i = 0; i < N; i++) {
      int t;
      cin >> t;
      if(X >> t & 1) {
        continue;
      }
      long long Y = (long long) 1 << (t + 1);
      long long Z = (long long) 1 << t;
      long long r = (X / Z + 1) * Z;
      long long l = X / Y * Y - 1;
      if(l < 0) {
        l = r;
      }
      L.emplace_back(l);
      R.emplace_back(r);
    }
    int sz = L.size();
    if(sz == 0) {
      cout << 0 << '\n';
    } else {
      long long ans = 8000000000000000000;
      for(int i = 0; i < sz; i++) {
        for(int j = 0; j < sz; j++) {
          long long l = L[i];
          long long r = R[j];
          if(l > r) {
            continue;
          }
          if(i == j) {
            bool fn = true;
            for(int k = 0; k < sz; k++) {
              if(l <= L[k] && L[k] <= X) {
                continue;
              }
              fn = false;
            }
            if(fn) {
              ans = min(ans, (X - l) * 2);
            }
            fn = true;
            for(int k = 0; k < sz; k++) {
              if(X <= R[k] && R[k] <= r) {
                continue;
              }
              fn = false;
            }
            if(fn) {
              ans = min(ans, (r - X) * 2);
            }
          } else {
            bool fn = true;
            for(int k = 0; k < sz; k++) {
              if((l <= L[k] && L[k] <= r) || (l <= R[k] && R[k] <= r)) {
                continue;
              }
              fn = false;
            }
            if(fn) {
              if(r <= X) {
                ans = min(ans, (X - l) * 2);
              } else if(l >= X) {
                ans = min(ans, (r - X) * 2);
              } else {
                ans = min(ans, (r - l) * 2);
              }
            }
          }
        }
      }
      cout << ans << '\n';
    }
  }
  return 0;
}