Edu Div2 B

#include <bits/stdc++.h>
using namespace std;
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
#define NeedForSpeed                  \
    ios_base::sync_with_stdio(false); \
    cin.tie(NULL);                    \
    cout.tie(NULL);
#define int long long
#define all(x) (x).begin(), (x).end()
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vpi;
#define f first
#define s second
#define endl "\n"
const int mod = 1000000007;
int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
void solve()
{
    int n;
    cin >> n;
    vi v(n);
    for (int i = 0; i < n; i++)
    {
        cin >> v[i];
    }
    sort(all(v));
    if (n == 1)
    {
        cout << 1 << endl;
        return;
    }
    if (n == 1)
    {
        cout << abs(v[1] - v[0]) << endl;
        return;
    }
    if ((n % 2) == 0)
    {
        // only 1 answer is possible
        int ans = 0;
        for (int i = 0; i < n; i += 2)
        {
            ans = max(ans, (v[i + 1] - v[i]));
        }
        cout << ans << endl;
    }
    else
    {
        // leave 1 element and do the same, as we can get a number closed to it
        int ans = 1e18;
        for (int i = 0; i < n; i += 2)
        {
            int ma1 = 0, ma2 = 0;
            for (int j = 0; j < i; j += 2)
            {
                ma1 = max(ma1, v[j + 1] - v[j]);
            }
            for (int j = i + 1; j < n; j += 2)
            {
                ma2 = max(ma2, v[j + 1] - v[j]);
            }
            ans = min(ans, max(ma1, ma2));
        }
        cout << ans << endl;
    }
    return;
}

signed main()
{
    NeedForSpeed;
    int t = 1;
    cin >> t;
    while (t--)
    {
        solve();
    }
    return 0;
}