Balanced Binary Tree Show result

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.

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Example

Given binary tree A={3,9,20,#,#,15,7}, B={3,#,20,15,7}

A)  3            B)    3 
   / \                  \
  9  20                 20
    /  \                / \
   15   7              15  7

The binary tree A is a height-balanced binary tree, but B is not.

public class Solution {

    /**

     * @param root: The root of binary tree.

     * @return: True if this Binary tree is Balanced, or false.

     */

    public boolean isBalanced(TreeNode root) {

        // write your code here

        return _isBalanced(root) == -1 ? false : true;

        

    }

    

    private int _isBalanced(TreeNode root){

        if(root == null) return 0;

        

        int left = _isBalanced(root.left);

        int right = _isBalanced(root.right);

        if(left == -1 || right == -1) return -1;

        if(Math.abs(left-right) > 1) return -1;

        return Math.max(left, right)+1;

    }

}