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

#define fwd(i, a, n) for (int i = (a); i < (n); i ++)
#define rep(i, n) fwd(i, 0, n)
#define all(X) begin(X), end(X)
#define sz(X) ((int)X.size())
#define st first
#define nd second
#define pii pair<int, int>
#define vi vector<int>
#define ll long long

#ifdef LOC
auto &operator<<(auto &out, pair<auto, auto> a) {
    return out << "(" << a.st << ", " << a.nd << ")";
}

auto &operator<<(auto &out, auto a) {
    out << "{";
    for (auto b : a)
        out << b << ", ";
    return out << "}";
}

void dump(auto... x) { ((cerr << x << ", "), ...) << '\n'; }
#define debug(x...) cerr << "[" #x "]: ", dump(x)
#else
#define debug(...) 0
#endif

int turbo(int v, vector<vi> &g, vi& mt, vi& vis){
    if(vis[v])return 0;
    vis[v] = 1;
    for(auto u : g[v]){
        if(mt[u] == -1 || turbo(mt[u], g, mt, vis)){
            mt[u] = v;
            mt[v] = u;
            return 1;
        }
    }
    return 0;
}

int turboMatching(vector<vi> &g, vi&mt){
    int n = sz(g);
    vi vis(n);
    int res = 0, flow = 1;
    while(flow){
        flow = 0;
        fill(all(vis), 0);
        rep(i, n){
            if(mt[i] == -1 && turbo(i, g, mt, vis)){
                flow++;
            }
        }
        res += flow;
    }
    return res;
}

void solve(){
    int n; cin>>n;
    vector<int> a(n);
    vector<int> b(n);
    rep(i, n)cin>>a[i];
    rep(i, n)cin>>b[i];
    vector<vector<int>> g(2*n);
    rep(i, 2*n)g[i].reserve(n);
    vector<int> mt(2*n, -1);
    int l = 0;
    int r = 1e9;
    while(l < r){
        int m = (l + r)/ 2 + 1;
        rep(i, 2*n)mt[i] = -1;
        rep(i, 2*n)g[i].clear();
        rep(i, n){
            rep(j, n){
                if(abs(a[i] - b[j]) >= m){
                    g[i].push_back(j + n);
                    g[j+ n].push_back(i);
                }
            }
        }
        if(turboMatching(g, mt) == n){
            l = m;
        }else{
            r = m-1;
        }
    }
    cout<<l<<"\n";
}

int32_t main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    int t; cin>>t;
    while(t--){
        solve();
    }
    return 0;
}