height balanced binary tree

基本解释

Given a binary tree, determine if it is height-balanced.
给出一个二叉树，判断它高度是不是平衡的。
For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees ofeverynode never differ by more than 1.
注意平衡树的定义，每一个点的左右子树高度差不超过1，并不是叶子结点的最大深度和最小深度不超过1。
For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
对于这个问题，一个高度平衡的二叉树是指每个节点的两个子节点的深度的差异都不超过1的二叉树。