import os
import sys
from io import BytesIO, IOBase

BUFSIZE = 8192


class FastIO(IOBase):
	newlines = 0
	
	def __init__(self, file):
		self._fd = file.fileno()
		self.buffer = BytesIO()
		self.writable = "x" in file.mode or "r" not in file.mode
		self.write = self.buffer.write if self.writable else None
	
	def read(self):
		while True:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			if not b:
				break
			ptr = self.buffer.tell()
			self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
		self.newlines = 0
		return self.buffer.read()
	
	def readline(self):
		while self.newlines == 0:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			self.newlines = b.count(b"\n")+(not b)
			ptr = self.buffer.tell()
			self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
		self.newlines -= 1
		return self.buffer.readline()
	
	def flush(self):
		if self.writable:
			os.write(self._fd, self.buffer.getvalue())
			self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
	def __init__(self, file):
		self.buffer = FastIO(file)
		self.flush = self.buffer.flush
		self.writable = self.buffer.writable
		self.write = lambda s:self.buffer.write(s.encode("ascii"))
		self.read = lambda:self.buffer.read().decode("ascii")
		self.readline = lambda:self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda:sys.stdin.readline().rstrip("\r\n")


def solve():
	n,x=map(int,input().split())
	c=list(map(int,input().split()))
	d = []
	for i in range(n):
		if x & (1 << c[i]) == 0: 
			d.append(c[i])
			
	n = len(d)

	if n == 0:
		print(0)
		return 

	lft=[-1]*n
	rgt=[-1]*n
	event = []
	now=[0]*n

	for i in range(n):
		rgt[i] = x // (1<<c[i]) * (1<<c[i]) + (1<<c[i])
		if rgt[i] & (1<<c[i]) == 0:
			rgt[i] += (1<<c[i])
		assert (rgt[i] & (1<<c[i])) > 0

		lft[i] = x // (1<<c[i]) * (1<<c[i])
		if (lft[i] & (1 << c[i])) > 0:
			lft[i] -= 1<<c[i]
		assert (lft[i] & (1<<c[i])) == 0
		lft[i] -= 1
		if lft[i] < 0:
			lft[i] = -1

		if lft[i] >= 0:
			event.append((lft[i],i))
			now[i] = lft[i]
		else:
			now[i] = rgt[i]

	#print(lft,rgt)

	ans = 2*(max(rgt)-x)
	if min(lft) >= 0:
		ans = min(ans, 2*(x-min(lft)))

	ans = min(ans, 2*abs(max(now) - x) + 2*abs(min(now) - x))
	event.sort()
	for i,j in event:
		now[j] = rgt[j]
		#print(now)
		ans = min(ans, 2*abs(max(now) - x) + 2*abs(min(now) - x))

	print(ans)


t=int(input())
for _ in range(t):
	solve()