#include <bits/stdc++.h>
#define pii pair <int, int>

using namespace std;

int NL, NR;

struct mazan{
    int val, cost;
    bool operator<(const mazan &other)const{
        return cost > other.cost;
    }
};

vector <mazan> vs[5001];
int lmatch[5001];
int rmatch[5001];
int visited[5001], iter;
int a[5001], b[5001];

bool dfs(int u, int mini)
{
    if(visited[u] < iter){
        visited[u] = iter;
        for(auto v : vs[u]){
            if(v.cost < mini)
                break;
            if(rmatch[v.val] == -1 || dfs(rmatch[v.val], mini)){
                lmatch[u] = v.val;
                rmatch[v.val] = u;
                return true;
            }
        }
    }
    return false;
}

int maxmatching(int mini){
    fill(lmatch, lmatch + NL, -1);
    fill(rmatch, rmatch + NR, -1);
    int m = 0, dm = 1;
    while(dm){
        dm = 0;
        iter++;
        for(int u = 0; u < NL; u++) if(lmatch[u] == -1)
            dm += dfs(u, mini);
        m += dm;
    }
    return m;
}

void solve() {
    int n;
    cin >> n;
    NL = NR = n;
    for(int i = 0; i < n; i++)
        cin >> a[i];
    for(int i = 0; i < n; i++)
        cin >> b[i];
    for(int i = 0; i < n; i++)
        vs[i].clear();
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            vs[i].push_back({j, abs(a[i] - b[j])});
    for(int i = 0; i < n; i++)
        sort(vs[i].begin(), vs[i].end());
    int r = -1, pas = 1 << 29;
    while(pas)
    {
        if(maxmatching(r + pas) == n)
            r += pas;
        pas /= 2;
    }
    cout << r << '\n';
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);

#ifdef LOCAL
    freopen("test.in", "r", stdin);
    freopen("test.out", "w", stdout);
#else

#endif
    int T = 1;
    cin >> T;
    while(T--) {
        solve();
    }
    return 0;
}