Java [Leetcode 110]Balanced Binary Tree

题目描述：

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.

解题思路：

递归法解题。

代码如下：

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public boolean isBalanced(TreeNode root) {
    	if(root == null)
    		return true;
    	else{
    		if(Math.abs(getHeight(root.left) - getHeight(root.right)) > 1)
    			return false;
    		else
    			return isBalanced(root.left) && isBalanced(root.right);
    	}
    }

    public int getHeight(TreeNode root){
    	if(root == null)
    		return 0;
    	else return 1 + Math.max(getHeight(root.left), getHeight(root.right));
    }
}