判断二叉树树是否是平衡二叉树

package com.tree;

public class IsBalanceTree {

    public static boolean isBalanceTree(TreeNode root,int[] dep){
        if(root==null){
            dep[0] = 0;
            return true;
        }
        int[] leftDep = new int[1];
        int[] rightDep = new int[1];
        if(isBalanceTree(root.left,leftDep)&&isBalanceTree(root.right,rightDep)){
            int diff = leftDep[0]-rightDep[0];

            if(diff>=-1&&diff<=1){
                dep[0] = 1 + (leftDep[0] > rightDep[0] ? leftDep[0] : rightDep[0]);
                return true;
            }

        }
        return false;

    }



    private class TreeNode {
        private TreeNode left;
        private TreeNode right;
        private Integer val;
        public TreeNode(Integer val) {
            this.val = val;
        }
    }
}