#include <bits/stdc++.h>   using namespace std;   void solve() {     int n;     cin >> n;     int arr[n];     for (int i = 0; i < n; i++) cin >> arr[i];     int i = n / 2 - 1, j = n / 2;     sort(arr, arr + n);     int x = 0;     int ans[n];     if (n % 2) ans[0] = arr[n / 2], x++, j++;     for (; i >= 0 && j < n; i--, j++) {       ans[x++] = arr[i];       ans[x++] = arr[j];     }     for (int i = 0; i < n; i++) cout << ans[i] <<    ;     cout << endl;   }   int32_t main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int t;     cin >> t;     while (t--) {       solve();     }     return 0;   }   