LeetCode: Maximum Depth of Binary Tree Jun 24 2015 12345678910111213141516/** * Created by hzhou on 4/27/15. [email protected] */public class MaximumDepthOfBinaryTree { public int maxDepth(TreeNode root) { return helper(root); } private int helper(TreeNode root) { if (root == null) { return 0; } else { return Math.max(helper(root.left), helper(root.right)) + 1; } }}