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

int main() {
    int t, n;
    scanf("%d", &t);
    while (t--) {
        scanf("%d", &n);
        vector<int> a(n), b(n);
        int best = 0;
        for (int& i : a) scanf("%d", &i);

        for (int& i : b) scanf("%d", &i);
        sort(a.begin(), a.end());
        sort(b.begin(), b.end());
        for (int l=0; l<=n; l++) {
            int cur = INT_MAX;
            for (int j=0; j<l; j++) cur = min(cur, abs(a[j]- b[n - l + j]));
            for (int j=l; j<n; j++) cur = min(cur, abs(a[j]- b[j - l]));
            best = max(best, cur);
            //printf("Test %d %d\n", l, cur);
        }
        printf("%d\n", best);
    }
}