LeetCode: 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 binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
private:
int getHeight(TreeNode *root){
if(!root) return 0;
return 1+max(getHeight(root->left),getHeight(root->right));
}
public:
bool isBalanced(TreeNode *root) {
if(!root) return true;
else return (isBalanced(root->left) && isBalanced(root->right) && abs(getHeight(root->left) - getHeight(root->right)) <=1);
}
};

还以为这种粗暴的递归无法通过测试呢，没想到直接accepted了！

那有没有什么好的算法实现呢？