C# Recursive Solution and explaination

[rileymckenna]

Using a recursive algorithm in C#.
Because this is a pre-order binary tree you must:

1. Check the root
2. Check the left branches
3. Check the right branches

In recursion, we want to establish a base case:

1. Where the root == null where we will return 0 as the depth.
2. Do work on the left branch, increment the depth counter by 1
3. Do work on the right branch, increment the depth counter by 1
4. Find the Max depth.

        public int MaxDepth(TreeNode root)
        {
            if(root == null)
            {
                return 0;
            }
            int ldepth = 1 + MaxDepth(root.left);
            int rdepth = 1 + MaxDepth(root.right);

            return Math.Max(ldepth,rdepth); 
        }