How to calculate max depth of given binary tree in c#

This is a continuation of my post How to create the binary tree in c#.In this post, I will show you how to calculate the max depth of a given binary tree in c#.

max depth of a tree – the number of nodes along the longest path from the root node down to the farthest leaf node.

  public int MaxDepth()
        {
            return MaxDepth(_root);
        }
        private int MaxDepth(Node root)
        {
            if (root == null)
                return -1;
            // compute the depth of each subtree 
            else
            {
                int leftDepth = MaxDepth(root.Left);
                int rightDepth = MaxDepth(root.Right);
                //Return max of left or right tree.
                return 1 + Math.Max(leftDepth, rightDepth);
            }
        }