from random import randint
from collections import deque

def solve():
    n = int(input())
    plist = list(map(int, input().split()))

    deq = deque()
    deq.append(plist[0])

    for i in range(1, n):
        p = plist[i]
        if randint(0,1) == 0:
            deq.appendleft(p)
        else:
            deq.append(p)
    print(0)
    print(*deq)

q = int(input())
while q:
    q -= 1
    solve()