def absdiff(xs, ys, offs):
    minoffs = 100000000000000000000
    for i in range(len(xs)):
        diff = abs(xs[i] - ys[(i + offs) % len(xs)])
        if diff < minoffs:
            minoffs = diff
    return minoffs

for _ in range(int(input())):
    n = int(input())
    ass = [int(i) for i in input().split()]
    bss = [int(i) for i in input().split()]
    ass.sort()
    bss.sort()
    mdiff = 0
    for offs in range(n):
        ds = absdiff(ass, bss, offs)
        if ds > mdiff:
            mdiff = ds
    print(mdiff)