#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<int> v(n);
    for (int i = 0; i < n; i++) cin >> v[i];
    string x = "", y = "";
    for (int i = 0; i < n; i++) {
      int l = x.length();
      for (int j = 1; j <= v[i] - l; j++) x += "a";
      if (v[i] == 0) {
        x += "a";
        y = (char)(((x[0] + 1 - 97) % 26) + 97);
      } else {
        y = "";
        for (int j = 1; j <= v[i]; j++) y += x[j - 1];
        for (int j = v[i]; j < x.length(); j++)
          y += (char)(((x[j] + 1 - 97) % 26) + 97);
      }
      cout << x << "\n";
      x = y;
    }
    cout << y << "\n";
  }
}
