Binary Tree Maximum Node

Find the maximum node in a binary tree, return the node.

Example

Given a binary tree:

     1
   /   \
 -5     2
 / \   /  \
0   3 -4  -5 

return the node with value 3.

public class Solution {
    /**
     * @param root the root of binary tree
     * @return the max ndoe
     */
    public TreeNode maxNode(TreeNode root) {
        // Write your code here
        if(root == null) return root;
        TreeNode leftMax = null;
        if(root.left!=null){
             leftMax = maxNode(root.left);
        }
        TreeNode rightMax = null;
        if(root.right!=null){
            rightMax = maxNode(root.right);
        }
        TreeNode max  = root;
        if(leftMax!=null){
            max = leftMax.val>max.val? leftMax : max;
        }
        if(rightMax!=null){
            max = rightMax.val>max.val? rightMax : max;
        }
        return max;
    }
}