#include <bits/stdc++.h>

using namespace std;
using ll = long long;

// bool possible(const vector<int>& a, const vector<int>& b, int diff) {
//     int a = 0;
//     int b = n;
//     while (a <= b) {
//         int mid = (a + b) / 2;
//         for (int i = 0; i < mid; i++) {

//         }
//     }
// }

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int t;
    cin >> t;
    for (int t1 = 0; t1 < t; t1++) {

        int n;
        cin >> n;
        vector<int> a(n);
        vector<int> 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());


        // int a = 0;
        // int b = 1e9 + 1;
        // int res = -1;
        // while (a <= b) {
        //     int mid = (a + b) / 2;
        //     if (possible(a, b, mid)) {
        //         res = mid;
        //         a = mid + 1;
        //     } else {
        //         b = mid - 1;
        //     }
        // }

        int best = -1;
        for (int k = 0; k <= n; k++) {
            int cur = 1e9;
            for (int i = 0; i < k; i++) {
                // cout << k << "a " << a[i] << " " << b[n + i - k] << endl;
                cur = min(cur, abs(a[i] - b[n + i - k]));
            }
            for (int i = k; i < n; i++) {
                // cout << k << "b " << a[i] << " " << b[i - k] << endl;
                cur = min(cur, abs(a[i] - b[i - k]));
            }
            // cout << k << " " << cur << endl;
            best = max(best, cur);
        }
        cout << best << "\n";
    }
}