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 diffe

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;
        int left=treeDepth(root.left);
        int right=treeDepth(root.right);
        if(Math.abs(left-right)<=1){//条件
            if(isBalanced(root.left)&&isBalanced(root.right))//递归调用isBanlianced(root);
                return true;
        }
        return false;
        
    }

    private int treeDepth(TreeNode root) {//求树的深度
        // TODO Auto-generated method stub
        if(root==null)return 0;
        
        return Math.max(treeDepth(root.right), treeDepth(root.left))+1;
    }
}