#include <bits/stdc++.h>
using namespace std;
const int inf = INT_MAX;
const long long int inf64 = LLONG_MAX;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long int t;
  cin >> t;
  while (t--) {
    long long int n;
    cin >> n;
    long long int arr[n], i;
    for (i = 0; i < n; i++) cin >> arr[i];
    vector<string> ans;
    string temp = string(200, 'a');
    ans.push_back(temp);
    for (i = 0; i < n; i++) {
      long long int curr = arr[i];
      string second;
      string last;
      last = ans.back();
      long long int j;
      for (j = 0; j < curr; j++) second.push_back(last[j]);
      if (last[j] == 'z') {
        char ch = 'a';
        while (second.length() < 200) second.push_back(ch);
      } else {
        char ch = last[j] + 1;
        while (second.length() < 200) second.push_back(ch);
      }
      ans.push_back(second);
    }
    for (auto x : ans) cout << x << '\n';
  }
  return 0;
}
