#include <bits/stdc++.h>
using namespace std;
int main() {
  int t = 1;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; ++i) cin >> a[i];
    int maxx = a[0];
    for (int i = 1; i < n; ++i) {
      maxx = max(maxx, a[i]);
    }
    string s;
    if (maxx == 0) s = "a";
    for (int i = 0; i < maxx; ++i) s = s + "a";
    cout << s << endl;
    for (int i = 0; i < n; ++i) {
      int index = a[i];
      for (int j = index; s[j]; ++j) {
        if (s[j] == 'z')
          s[j] = 'a';
        else
          s[j] = s[j] + 1;
      }
      cout << s << endl;
    }
  }
  return 0;
}
