#include<bits/stdc++.h>

using namespace std;

#define int long long
#define double long double
#define vi vector<int>

#define pii pair<int,int>
#define vii vector<pii>

#define fi first
#define se second

#define pb push_back
const double eps=1e-12;

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t;
    cin >> t;
    while (t--){
        int n;
        cin >> n;
        vi 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());

        int res=0;
        for (int l=0;l<=n;l++){
            int ans=1e9;
            for (int i=0;i<l;i++) ans=min(ans,abs(a[i]-b[n-l+i]));
            for (int i=l;i<n;i++) ans=min(ans,abs(a[i]-b[i-l]));
            res=max(res,ans);
        }

        cout << res << '\n';

    }
}