Node<V> untreeify(Node<V> b) {
      Node<V> hd = null, tl = null;
      for (Node<V> q = b; q != null; q = q.next) {
          Node<V> p = new Node<V>(q.hash, q.key, q.val, null);
          if (tl == null)
              hd = p;
          else
              tl.next = p;
          tl = p;
      }
      return hd;
  }
Node<V> untreeify(Node<V> b)