source_code: 
  
  /*
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   * and open the template in the editor.
   */
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.StringTokenizer;
  
  /**
   *
   * @author is2ac
   */
  public class C_CF {
  
      public static void main(String[] args) {
          FastScanner57 fs = new FastScanner57();
          PrintWriter pw = new PrintWriter(System.out);
          int t = fs.ni();
          //int t = 1;
          for (int tc = 0; tc < t; tc++) {
              int n = fs.ni();
              int[] q = new int[n+5];
              int ind = 0;
              q[0] = 1;
              for (int i = 0; i < n; i++) {
                  int a = fs.ni();
                  while (q[ind]!=a) ind--;
                  StringBuilder sb = new StringBuilder();
                  for (int j = 0; j < ind; j++) {
                      sb.append(q[j]-1);
                      sb.append(".");
                  }
                      sb.append(a);
                      q[ind]++;
                      q[ind+1] = 1;
                      ind++;
                      pw.println(sb);
              }
          }
          pw.close();
  
      }
  
      static class BIT18 {
  
          int[] bit;
  
          public BIT18(int size) {
              bit = new int[size];
          }
  
          public void update(int ind, int delta) {
              while (ind < bit.length) {
                  bit[ind] += delta;
                  ind = ind + (ind & (-1 * ind));
              }
          }
  
          public int sum(int ind) {
              int s = 0;
              while (ind > 0) {
                  s += bit[ind];
                  ind = ind - (ind & (-1 * ind));
              }
              return s;
          }
  
          public int query(int l, int r) {
              return sum(r) - sum(l);
          }
      }
  
      // 0 -> left was chosen
      // 1 -> right was chosen
      public static long recur(int ind, int p, int prev, long[] v, Long[][] dp, long[][] lr, List<List<Integer>> list) {
  
          long last = v[0];
          long ls = 0L;
          long rs = 0L;
          if (p == 1) {
              last = v[1];
          }
          if (ind != 0) {
              ls += (long) Math.abs(last - lr[ind][0]);
          }
          if (ind != 0) {
              rs += (long) Math.abs(last - lr[ind][1]);
          }
          if (dp[ind][p] != null) {
              return dp[ind][p];
          }
          long[] cur = lr[ind];
  
          List<Integer> temp = list.get(ind);
          for (int val : temp) {
              if (prev == val) {
                  continue;
              }
              ls += recur(val, 0, ind, cur, dp, lr, list);
              rs += recur(val, 1, ind, cur, dp, lr, list);
          }
          return dp[ind][p] = Math.max(ls, rs);
      }
  
      public static void sort(long[] a) {
          List<Long> list = new ArrayList();
          for (int i = 0; i < a.length; i++) {
              list.add(a[i]);
          }
          Collections.sort(list);
          for (int i = 0; i < a.length; i++) {
              a[i] = list.get(i);
          }
      }
  
      public static long gcd(long n1, long n2) {
          if (n2 == 0) {
              return n1;
          }
          return gcd(n2, n1 % n2);
      }
  
  }
  
  class UnionFind16 {
  
      int[] id;
  
      public UnionFind16(int size) {
          id = new int[size];
          for (int i = 0; i < size; i++) {
              id[i] = i;
          }
      }
  
      public int find(int p) {
          int root = p;
          while (root != id[root]) {
              root = id[root];
          }
          while (p != root) {
              int next = id[p];
              id[p] = root;
              p = next;
          }
          return root;
      }
  
      public void union(int p, int q) {
          int a = find(p), b = find(q);
          if (a == b) {
              return;
          }
          id[b] = a;
      }
  }
  
  class FastScanner57 {
  
      BufferedReader br;
      StringTokenizer st;
  
      public FastScanner57() {
          br = new BufferedReader(new InputStreamReader(System.in), 32768);
          st = null;
      }
  
      String next() {
          while (st == null || !st.hasMoreElements()) {
              try {
                  st = new StringTokenizer(br.readLine());
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          return st.nextToken();
      }
  
      int ni() {
          return Integer.parseInt(next());
      }
  
      int[] intArray(int N) {
          int[] ret = new int[N];
          for (int i = 0; i < N; i++) {
              ret[i] = ni();
          }
          return ret;
      }
  
      long nl() {
          return Long.parseLong(next());
      }
  
      long[] longArray(int N) {
          long[] ret = new long[N];
          for (int i = 0; i < N; i++) {
              ret[i] = nl();
          }
          return ret;
      }
  
      double nd() {
          return Double.parseDouble(next());
      }
  
      String nextLine() {
          String str = "";
          try {
              str = br.readLine();
          } catch (IOException e) {
              e.printStackTrace();
          }
          return str;
      }
  }
  