source_code: import java.io.*;
  import java.util.*;
  
  public class q3 {
  
      public static void main(String[] args) throws Exception {
          // String[] parts=br.readLine().split(" ");
          // int n=Integer.parseInt(parts[0]);
          // int k=Integer.parseInt(parts[1]);
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          int tests = Integer.parseInt(br.readLine());
  
          for (int test = 1;test <= tests;test++) {
              String[] parts = br.readLine().split(" ");
              int n = Integer.parseInt(parts[0]);
              
              StringBuilder temp = new StringBuilder();
  
              int curr = Integer.parseInt(br.readLine());
              temp.append("1");
              System.out.println(1);
              for(int i = 0;i < n - 1;i++){
                  curr = Integer.parseInt(br.readLine());
                  if(curr == 1){
                      temp.append('.').append('1');
                      System.out.println(temp);
                  }else{
                      while(temp.length() > 0){
                          int idx = temp.length() - 1;
                          while(idx >= 0 && temp.charAt(idx) != '.') idx--;
                          idx++;
  
                          int val = Integer.parseInt(temp.substring(idx));
                          temp.delete(idx,temp.length());
                          if(curr == val + 1){
                              temp.append(String.valueOf(curr));
                              break;
                          }
                          temp.deleteCharAt(temp.length() - 1);
                      }
                      System.out.println(temp);
                  }
              }
          }
      }
  }
  