source_code: import javax.print.DocFlavor;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Scanner;
  import java.util.Stack;
  
  public class p1523C {
      public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          int t = sc.nextInt();
          for (int i = 0; i < t ; i++) {
              int n = sc.nextInt();
              ArrayList<Stack<Integer>> ar = new ArrayList<Stack<Integer>>();
              for (int j = 0; j < n + 1; j++) {
                  ar.add(new Stack<Integer>());
              }
              HashMap <Integer , Integer> hm = new HashMap<Integer, Integer>();
              StringBuilder cur = new StringBuilder();
              int l = 0;
              for (int j = 0; j < n; j++) {
                  int a = sc.nextInt();
                  if( a == 1)
                  {
                      if(cur.length() == 0)
                          cur.append("1");
                      else
                          cur.append(".1");
                      l++;
                      ar.get(1).add(l);
                      hm.put(l , 1);
                  }
                  else
                  {
                      int newl = ar.get( a - 1).pop();
                      for (int k = newl + 1; k <= l ; k++) {
                          ar.get(hm.get(k)).pop();
                          hm.remove(k);
                          cur.delete(cur.lastIndexOf(".")  + 1, cur.length());
                          cur.delete(cur.length() - 1 , cur.length());
                      }
                      cur.delete(cur.lastIndexOf(".")  + 1, cur.length());
                      cur.append(a);
                      ar.get(a).add(newl);
                      hm.put(newl , a);
                      l = newl;
                  }
                  System.out.println(cur);
              }
  
          }
      }
  }
  