public class Solution {

    //判断根节点左右子树的深度，高度差超过1，则不平衡

    public boolean IsBalanced_Solution(TreeNode root) {

        if (root==null) {

            return true;

        }

        int left = getTreeDepth(root.left);

        int right = getTreeDepth(root.right);

        return Math.abs(left-right)>1?false:true;

    }

    //求取节点的深度

    public static int getTreeDepth(TreeNode root) {

        if (root==null) {

            return 0;

        }

        int leftDepth = 1+getTreeDepth(root.left);

        int rightDepth = 1+getTreeDepth(root.right);

        return leftDepth>rightDepth?leftDepth:rightDepth;

    }

}