#include<bits/stdc++.h>

#pragma GCC optimize ("Ofast")

using namespace std;

#define rep(i,a,b) for(ll i = a; i<b;i++)
#define sz(v) ll(v.size())
#define all(v) v.begin(),v.end()

typedef long long ll;
typedef long double ld;
typedef vector<ll> vl;
typedef pair<ll,ll> pll;

void solve()
{
    ll n;
    cin >> n;

    vector<ll> a(n);
    vector<ll> b(n);

    for (ll i = 0; i < n; i++) cin >> a[i];
    for (ll i = 0; i < n; i++) cin >> b[i];

    sort(all(a));
    sort(all(b));

    ll res = 0;

    for (ll s = 0; s <= n; s++)
    {
        ll cr = 1e15;

        for (ll i = 0; i < s; i++)
        {
            cr = min(cr, abs(a[i] - b[n - s + i]));
        }
        for (ll i = s; i < n; i++)
        {
            cr = min(cr, abs(a[i] - b[i - s]));
        }
        res = max(res, cr);
    }
    cout << res << "\n";
}

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

    int t;
    cin >> t;

    while (t--) solve();
}