for t in range(int(input())):
n = int(input())
a = sorted(map(int, input().split()))
b = sorted(map(int, input().split()))
print(max(
min(abs(x - y) for x, y in zip(a, b[i:] + b[:i])) for i in range(n)
))
221A - Little Elephant and Function | 492C - Vanya and Exams |
1369B - AccurateLee | 892B - Wrath |
999A - Mishka and Contest | 727C - Guess the Array |
1625C - Road Optimization | 1715D - 2+ doors |
267A - Subtractions | 1582A - Luntik and Concerts |
560A - Currency System in Geraldion | 946A - Partition |
1068B - LCM | 1692E - Binary Deque |
679A - Bear and Prime 100 | 488A - Giga Tower |
14A - Letter | 1150A - Stock Arbitraging |
1552A - Subsequence Permutation | 1131F - Asya And Kittens |
1475F - Unusual Matrix | 133B - Unary |
1547A - Shortest Path with Obstacle | 624A - Save Luke |
1238A - Prime Subtraction | 1107C - Brutality |
1391B - Fix You | 988B - Substrings Sort |
312A - Whose sentence is it | 513A - Game |