题目
Given a binary tree, determine if it is height-balanced.
For this problem, a height-balanced binary tree is defined as:
a binary tree in which the left and right subtrees of every node differ in height by no more than 1.
解题思路
递归，如果一个树是平衡的，那么两个子树也是平衡的，并且高度最多差1
代码
class Solution:
def isBalanced(self, root: TreeNode) -> bool:
def dfs(root):
if not root:
return True, 0
bl, hl = dfs(root.left)
if not bl:
return False, 0
br, hr = dfs(root.right)
if not br:
return False, 0
return abs(hl - hr) <= 1, max(hl, hr) + 1
return dfs(root)[0]
