#include <bits/stdc++.h>
#define int long long
using namespace std;

void solve() {
    int n; cin >> n;
    vector<int> a(n), b(n);
    for (auto& i : a) cin >> i;
    for (auto& i : b) cin >> i;
    sort(a.begin(), a.end());
    sort(b.begin(), b.end());
    int res = 0;
    for (int sz = 0; sz <= n; sz++) {
        int tmp = 2e9;
        for (int i = 0; i < sz; i++) {
            int j = n - sz + i;
            tmp = min(tmp, abs(a[i] - b[j]));
        }
        for (int i = sz; i < n; i++) {
            int j = i - sz;
            tmp = min(tmp, abs(a[i] - b[j]));
        }
        res = max(res, tmp);
    }
    cout << res << '\n';
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t; cin >> t;
    while (t--)
        solve();
    return 0;
}