class SegTree:
    def __init__(self, op, e, n, v=None):
        self._n = n
        self._op = op
        self._e = e
        self._log = (n - 1).bit_length()
        self._size = 1 << self._log
        self._d = [self._e()] * (self._size << 1)
        if v is not None:
            for i in range(self._n):
                self._d[self._size + i] = v[i]
            for i in range(self._size - 1, 0, -1):
                self._d[i] = self._op(self._d[i << 1], self._d[i << 1 | 1])

    def set(self, p, x):
        p += self._size
        self._d[p] = x
        while p:
            l, r = p, p^1
            if l > r: l, r = r, l
            self._d[p >> 1] = self._op(self._d[l], self._d[r])
            p >>= 1

    def get(self, p):
        return self._d[p + self._size]

    #[l, r)の区間で求める
    def prod(self, l, r):
        sml, smr = self._e(), self._e()
        l += self._size
        r += self._size
        while l < r:
            if l & 1:
                sml = self._op(sml, self._d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self._op(self._d[r], smr)
            l >>= 1
            r >>= 1
        return self._op(sml, smr)

    def all_prod(self):
        return self._d[1]

def op(x, y):
    return max(x, y)

def e():
    return 0

import sys
input = sys.stdin.readline
T = int(input())
for _ in range(T):
    N, X = map(int, input().split())
    C = list(map(int, input().split()))
    L = []
    R = []
    INF = 1<<60
    for c in C:
        if (X>>c)&1:
            R.append(X)
            L.append((X, len(L)))
        else:
            r = X|(1<<c)
            r -= r%(1<<c)
            R.append(r)
            if X<(1<<c):
                L.append((-INF, len(L)))
            else:
                l = X|((1<<c)-1)
                for i in range(c, 60):
                    if (l>>i)&1:
                        l-=(1<<i)
                        break
                    else:
                        l|=(1<<i)
                L.append((l, len(L)))
    #print(L)
    #print(R)
    ST = SegTree(op, e, N, R)
    L.sort(key=lambda x:-x[0])
    l = X
    ans = INF<<2
    for i in range(N):
        r = ST.all_prod()
        ans = min(ans, (X-l)*2+(r-X)*2)
        l, j = L[i]
        ST.set(j, 0)
    ans = min(ans, (X-l)*2)
    print(ans)