#include <bits/stdc++.h>
using namespace std;
using LL=long long;
#define FOR(i, l, r)for(int i = (l); i<=(r);++i)
#define REP(i, n)FOR(i,0,(n)-1)
#define ssize(x)int(x.size())

// auto&operator<<(auto&o,pair<auto, auto>p) {
//     return o << "(" << p.first << ", " << p.second << ")";
// }
// auto operator(auto&o, auto x)->decltype(x.end(),o){
//     o<<"{";inti=0;for(auto e:x)o<<", "+!i++<<e;return o<<"}";}


struct Matching {
    vector<vector<int>> &adj;
    vector<int> mat, vis;
    int t = 0, ans = 0;
    bool mat_dfs(int v) {
        vis[v] = t;
        for (int u : adj[v]) {
            if (mat[u] == -1) {
                mat[u]= v;
                mat[v] = u;
                return true;
            }
        }
        for (int u : adj[v]) {
            if (vis[mat[u]] != t && mat_dfs(mat[u])) {
                mat[u] = v;
                mat[v] = u;
                return true;
            }
        }
        return false;
    }
    Matching(vector<vector<int>>& _adj) : adj(_adj) {
        mat = vis = vector<int>(ssize(adj), -1);
    }

    pair<int, vector<int>> operator()() {
        int d = -1;
        while (d != 0) {
            d = 0, ++t;
            REP(v, ssize(adj))
                if (mat[v] == -1)
                    d += mat_dfs(v);
            ans += d;
        }
        return {ans, mat};
    }
};

bool ok(int ile, const vector<int>& A, const vector<int>& B) {
    // buduje graf, akceptuje tylko wierzcholki o roznicy abs(x, y) >= ile
    // cout << "Testuje teze " << ile << endl;
    vector<vector<int>> adj(A.size() + B.size());
    const int offset = A.size();
    for (int i = 0; i < A.size(); i++) {
        // cout << "Sasiedzi " << A[i] << endl;
        for (int j = 0; j < B.size(); j++) {
            if (abs(A[i] - B[j]) >= ile) {
                // cout << B[j] << ",";
                adj[i].push_back(j + offset);
                adj[j + offset].push_back(i);
            }
            // cout << endl;
        }
    }
    // cout << "Stworzony graf: \n";
    // for (auto sas : adj) {
    //     for (auto x : sas) {
    //         cout << x << ", ";
    //     }
    //     cout << endl;
    // }
    // cout << "\n";
    Matching m(adj);
    auto [m_size, match] = m();
    // if (m_size == A.size()) {
    //     cout << "OK\n";
    // } else {
    //     cout << "ZLE\n";
    // }
    return m_size == A.size();
}


void solve() {
    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];
    }

    // binsercz po wyniku
    int pocz = 0;
    int kon = 1e9 + 5;
    int mid;
    while (pocz < kon) {
        mid = (pocz + kon + 1) / 2;
        if (!ok(mid, A, B)) {
            // cout << "Teza " << mid << "nie ok\n";
            kon = mid - 1;
        } else {
            // cout << "Teza " << mid << "ok\n";
            pocz = mid;
        }
    }
    cout << pocz << "\n";
}


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