private static class BinaryNode {
    final int x;
    final Optional<BinaryNode> left;
    final Optional<BinaryNode> right;

    BinaryNode(int x, Optional<BinaryNode> left, Optional<BinaryNode> right) {
      this.x = x;
      this.left = left;
      this.right = right;
    }
  }

  enum Topology {
    BALANCED {
      @Override
      Optional<BinaryNode> createTree(int size, Random rng) {

                                </div>
                                <div class="form-group row">
                                    <label for="name" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.name"/></label>
                                    <div class="col-sm-9">
                                        <la:errors property="name"/>

      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Float[] concat(Float[] left, Float[] right) {
    Float[] result = new Float[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);
    System.arraycopy(right, 0, result, left.length, right.length);
    return result;
  }

  public abstract static class TestFloatListGenerator implements TestListGenerator<Float> {

                                </div>
                                <div class="form-group row">
                                    <label for="hostname" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.webauth_hostname"/></label>
                                    <div class="col-sm-9">

                                </div>
                                <div class="form-group row">
                                    <label for="term" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.related_content_term"/></label>
                                    <div class="col-sm-9">

                        </h1>
                    </div>
                    <div class="col-sm-6">
                        <ol class="breadcrumb float-sm-right">
                            <li class="breadcrumb-item"><la:link href="/admin/wizard/">
                                <la:message key="labels.wizard_start_title"/>
                            </la:link></li>

                                </div>
                                <div class="form-group row">
                                    <label for="name" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.access_token_name"/></label>
                                    <div class="col-sm-9">

      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Short[] concat(Short[] left, Short[] right) {
    Short[] result = new Short[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);
    System.arraycopy(right, 0, result, left.length, right.length);
    return result;
  }

  public abstract static class TestShortListGenerator implements TestListGenerator<Short> {

      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Integer[] concat(Integer[] left, Integer[] right) {
    Integer[] result = new Integer[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);
    System.arraycopy(right, 0, result, left.length, right.length);
    return result;
  }

  public abstract static class TestIntegerListGenerator implements TestListGenerator<Integer> {

      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Byte[] concat(Byte[] left, Byte[] right) {
    Byte[] result = new Byte[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);
    System.arraycopy(right, 0, result, left.length, right.length);
    return result;
  }

  public abstract static class TestByteListGenerator implements TestListGenerator<Byte> {