#include <iostream>
#include <bits/stdc++.h>

using namespace std;
typedef long long int ll;

int main() {
    ll t;
    cin >> t;
    while (t--) {
        ll n;
        cin >> n;
        vector<ll> a(n), b(n);
        for (int i = 0; i < n; ++i) {
            cin >> a[i];
        }
        for (int i = 0; i < n; ++i) {
            cin >> b[i];
        }
        sort(a.begin(), a.end());
        sort(b.begin(), b.end());
        ll ans = LONG_LONG_MIN;
        for (int i = 0; i < n; ++i) {
            ll curMin = LONG_LONG_MAX;
            for (int j = 0; j < i; ++j) {
                curMin = min(curMin, abs(a[j] - b[n - i + j]));
            }
            for (int j = i; j < n; ++j) {
                curMin = min(curMin, abs(a[j] - b[j - i]));
            }
            ans = max(ans, curMin);
        }
        cout << ans << endl;
    }

    return 0;
}