#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
int x[1005],y[1005],r[1005];
vector<int> v[1005];
bool ok[1005];
int nr,nr1;
bool valid;
int le[1005];

const int N = 1e4;
int a[N], b[N];

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

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

    sort (a, a + n);
    sort (b, b + n);
    int res = 0;
    for (int i = 0; i < n; ++i) {
        int cur = 1e9, n1 = n - i;
        for (int j = 0; j < n1; ++j)
            cur = min (cur, abs (a[i + j] - b[j]));
        for (int j = 0; j < n - n1; ++j)
            cur = min (cur, abs (a[j] - b[n1 + j]));
        res = max (res, cur);
    }
    cout << res << "\n";
    return ;
}
int32_t main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t = 1;
    cin >> t;
    while(t--) {
        find();
    }
    return 0;
}