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


bool check(int mid, vector<int> & a, vector<int> & b, int n){
    for(int i = 0; i < n; i++) {
        bool cond = true;
        for(int j = 0; j < n; j++) {
            if(j < i) {
                if(abs(a[j] - b[j + n - i]) < mid) cond = false;
            } else {
                if(abs(a[j] - b[j - i]) < mid) cond = false;
            }
        }
        if(cond) return true;
    }
    return false;
}
void solve(){
    int n; cin >> n; 
    vector<int> a(n), b(n); 

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

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

    for(int i = 0; i < n; i++) {
        
    }

    int first = 0, last = 1e9; 
    while (first < last){
        int mid = (first + last + 1) / 2; 
        if (check(mid, a, b, n)) first = mid; 
        else last = mid - 1; 
    }
    cout << first << "\n"; 
}

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