#include "bits/stdc++.h"
using namespace std;
using LL = long long;
using ll = long long;

#define all(x) begin(x),end(x)

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int t;
	cin >> t;
	while(t--) {	
		int n; cin >> n;
		vector < ll > a(n), b(n);
		for (auto &x : a)
			cin >> x;
		for (auto &x : b)
			cin >> x;
		sort(a.rbegin(), a.rend());
		sort(b.rbegin(), b.rend());

		ll ans = 0;
		for (int i = 0; i <= n; i++) {
			ll cur = 1ll<<60;
			for (int j = 0; j < i; j++) {
				cur = min(cur, a[j]-b[j+(n-i)]);
			}
			for (int j = 0; j < n-i; j++) {
				cur = min(cur, b[j]-a[i+j]);
			}
			ans = max(ans, cur);
		}
		cout << ans << "\n";
	}
}