source_code: import java.io.*;
  import java.util.StringTokenizer;
  
  public class C2 {
      String filename = null;
      InputReader sc;
  
      void solve() {
          int n = sc.nextInt();
          int[] a = sc.nextArray(n);
  
          int[] ps = new int[n];
          int[] q = new int[n];
          int[] qs = new int[n];
          int nq = 0;
          for (int i = 1; i < n; i++) {
              if (a[i] == 1) {
                  qs[nq] = i - 1;
                  q[nq++] = a[i - 1] + 1;
                  ps[i] = i - 1;
              } else {
                  if (a[i] == a[i - 1] + 1) {
                      qs[nq] = i - 1;
                      q[nq++] = 1;
                      ps[i] = i - 1;
                  } else {
                      for (int j = nq - 1; j >= 0; j--) {
                          if (a[i] == q[j]) {
                              ps[i] = qs[j];
                              nq = j;
                              break;
                          }
                      }
                  }
              }
          }
  
          int[] parents = ps;
          String[] strs = new String[n];
          strs[0] = "1";
          System.out.println(strs[0]);
          for (int i = 1; i < n; i++) {
              String p = strs[parents[i]];
              if (a[i] == 1) {
                  strs[i] = p + ".1";
              } else {
                  int lastDot = p.lastIndexOf(".");
                  if (lastDot == -1) {
                      strs[i] = a[i] + "";
                  } else {
                      strs[i] = p.substring(0, lastDot) + "." + a[i];
                  }
              }
              System.out.println(strs[i]);
          }
      }
  
      public void run() throws FileNotFoundException {
          if (filename == null) {
              sc = new InputReader(System.in);
          } else {
              sc = new InputReader(new FileInputStream(new File(filename)));
          }
  
          int nTests = sc.nextInt();
          for (int test = 0; test < nTests; test++) {
              solve();
          }
      }
  
      public static void main(String[] args) {
          C2 sol = new C2();
          try {
              sol.run();
          } catch (FileNotFoundException e) {
              e.printStackTrace();
          }
      }
  
      class InputReader {
          public BufferedReader reader;
          public StringTokenizer tokenizer;
  
          public InputReader(InputStream stream) {
              reader = new BufferedReader(new InputStreamReader(stream), 32768);
              tokenizer = null;
          }
  
          public String next() {
              while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                  try {
                      tokenizer = new StringTokenizer(reader.readLine());
                  } catch (IOException e) {
                      throw new RuntimeException(e);
                  }
              }
              return tokenizer.nextToken();
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public float nextFloat() {
              return Float.parseFloat(next());
          }
  
          public double nextDouble() {
              return Float.parseFloat(next());
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
  
          public int[] nextArray(int n) {
              int[] a = new int[n];
              for (int i = 0; i < n; i++) {
                  a[i] = nextInt();
              }
              return a;
          }
      }
  }