public class BalancedApp {
  public static void main(String[] args) {
    BinaryTree<String> t = new BinaryTree<>("Daniel",
                       new BinaryTree<>("Judy",
                         new BinaryTree<>("Shirley"),
                         new BinaryTree<>("Wendell")
                       ),
                       new BinaryTree<>("William",
                         new BinaryTree<>("Clairinda"),
                         new BinaryTree<>("Alexander",
                           new BinaryTree<>("Anastasia"),
                           new BinaryTree<>("Vladimir")
                         )
                       )
                     );
                        
    System.out.println(isBalanced(t));
  }
  
  public static <T> boolean isBalanced(BinaryTree<T> t) {
    if (t == null) {
      return true;
    } else {
      int hdiff = Math.abs(
			BinaryTree.getHeight(t.getLeft())
			- BinaryTree.getHeight(t.getRight())
		  );
      if (hdiff > 1) {
        return false;
      } else {
        return isBalanced(t.getLeft()) && isBalanced(t.getRight());
      }
    }
  }
  
}