Maximum Depth of 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.

与Maximum Depth of Binary Tree类似。

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    bool isBalanced(TreeNode *root) {        return balanceHeight(root) >= 0;            }        int balanceHeight(TreeNode * root)    {        if(root == 0)            return 0;        int lTreeHeight = balanceHeight(root -> left);        int rTreeHeight = balanceHeight(root -> right);                if(lTreeHeight < 0 || rTreeHeight < 0 || abs(lTreeHeight - rTreeHeight) > 1)            return -1;                return max(lTreeHeight,rTreeHeight) + 1;    }};