func_code_string: #include <bits/stdc++.h>   using namespace std;   const int sz = 1e5 + 100;   const int INF = 1e9;   const double eps = 1e-7;   void solve() {     int n;     cin >> n;     vector<long long> a(n + 1, 0);     for (int i = 0; i < n; i++) {       cin >> a[i];     }     sort(a.begin(), a.begin() + n);     for (int i = n - 1; i > -1; i--) {       cout << a[i % 2 ? n - 1 - i / 2 : i / 2] <<    ;     }     cout << endl;   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     int t;     cin >> t;     while (t--) solve();     return 0;   }   