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

#define rep(i, a, b) for(int i = a; i < (b); i++)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<ll> vi;

bool possible(vi& a, vi& b, ll charm) {
  ll rpossible = 0;
  rep(r, 0, sz(a)) {
  }

  // all pairs have at least charm diff
  int j = 0;
  vi skipped;
  rep(i, 0, sz(a)) {
    while (j < sz(b) && abs(b[j]-a[i]) < charm) {
      // add b[j] to skipped
      skipped.push_back(b[j]);
      j++;
    }
    if (j < sz(b)) {
      // take
      j++;
    } else {
      rep(k, i, sz(a)) {
        if (sz(skipped) > k-i && abs(a[k]-skipped[k-i]) < charm) {
          return false;
        }
      }
      return true;
    }
  }
  return true;
}

void solve() {
  int N; cin >> N;
  vi a(N);
  vi b(N);
  rep(i, 0, N) cin >> a[i];
  rep(i, 0, N) cin >> b[i];
  sort(all(a));
  sort(all(b));

  ll lo=0; // possible 
  ll hi=2e9; // impossible
  while (lo + 1 < hi) {
    ll mid = (lo+hi)/2;
    bool p = possible(a, b, mid);
    cerr << "mid=" << mid << " possible=" << p << endl;
    if (p) {
      lo = mid;
    } else {
      hi = mid;
    }
  }
  cout << lo << endl;
}

void solve2() {
  int N; cin >> N;
  vi a(N);
  vi b(N);
  rep(i, 0, N) cin >> a[i];
  rep(i, 0, N) cin >> b[i];
  sort(all(a));
  sort(all(b));

  ll ans = 0;
  rep(r, 0, N) {
    ll thismincharm = 1e18;
    ll rc = N-r;
    rep(i, 0, r) {
      thismincharm = min(thismincharm, abs(b[rc+i]-a[i]));
    }
    rep(i, 0, rc) {
      thismincharm = min(thismincharm, abs(b[i]-a[r+i]));
    }
    ans = max(ans, thismincharm);
  }
  cout << ans << endl;
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);

  int T; cin >> T;
  rep(i, 0, T) solve2();
}