#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;


int main(){
    
    ll t;
    cin >> t;

    while(t){

        ll n;
        cin >> n;

        vector<ll> a;
        vector<ll> b;
        
        for(ll i = 0; i < n; i++){
            ll x;
            cin >> x;
            a.push_back(x);
        }
        for(ll i = 0; i < n; i++){
            ll x;
            cin >> x;
            b.push_back(x);
        }

        sort(a.begin(),a.end());
        sort(b.begin(),b.end());

        ll record = 0;

        for(int shift = 0; shift < n; shift++){
            ll worst_pair = -1;
            for(int i = 0; i < n; i++){
                ll other = i+shift;
                if(other >= n){
                    other -= n;
                }
                ll diff = a[i] - b[other];
                if(diff < 0){
                    diff *= -1;
                }
                if(diff < worst_pair || worst_pair == -1){
                    worst_pair = diff;
                }
            }
            if(worst_pair > record){
                record = worst_pair;
            }
        }

        cout << record << endl;


        t--;
    }

}