题目描述
输入一棵二叉树，判断该二叉树是否是平衡二叉树。

public class Solution {
    
    public boolean IsBalanced_Solution(TreeNode root) {
        
        if(root == null)
            return true;
        if(!IsBalanced_Solution(root.left))
            return false;
        if(!IsBalanced_Solution(root.right))
            return false;
        int left = depth(root.left);
        int right = depth(root.right);
        if(Math.abs(left - right) <= 1)
            return true;
        else 
            return false;
    }
    private int depth(TreeNode root) {
        
        if(root == null)
            return 0;
        return Math.max(depth(root.left), depth(root.right)) + 1;
    }
}