Leetcode (Python): Balanced Binary Tree

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 depth of the two subtrees of every node never differ by more than 1.

Solution:

# Definition for a  binary tree node
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param root, a tree node
    # @return a boolean
    def isBalanced(self, root):
        return self.isBalancedInt(root)>=0
        
    def isBalancedInt(self, root):
        if root == None:
            return 0;
        left = self.isBalancedInt(root.left)
        right = self.isBalancedInt(root.right)
        if left<0 or right<0 or abs(left-right)>1:
            return -1
        return max(left,right)+1