Prepare binary search tree inorder successor problem statement

Prepare the question BST inorder successor

https://i.stack.imgur.com/OWd4M.jpg

Given the node with value 14, its inorder successor is 20; given the node with value 25, 
its inorder successor is null. given the node with value 9, its inorder successor is 11.

internal class TreeNode
{
   public int      Value { get; set; }
   public TreeNode Left  { get; set; }
   public TreeNode Right { get; set; }

   public TreeNode(int number)
   {
     Value = number;
   }
}                     

The above binary search tree can be drawn in the following:

        20
      /     \
    9        25
   / \ 
  5   12  
     /   \
    11     14

Given the above binary search tree, given node g has three cases. One is the root node;
the second case is in the right subtree of root node; the third case is in the left subtree
of root node. Let us look at the binary search inorder traversal sequence and see the position
of given node g in the diagram:

5  9   11   12  14   20   25
                     |
                     g   
                          g                               
  g

Let us use the hint: 
For example, you are very lazy and busy, given node g's value is bigger than 20, 
case 1: > 20, from root 20's -> 20's right child to complete the task 
case 2: given node is in left subtree, 
 one case is that 20 > given node's successor. we can give the task to its left 
 subtree, and it is fine.

Function prototype:       
FindBinarySearchTreeInOrderSuccessor(TreeNode root, TreeNode givenNode)

Written by Jianmin Chen 1/6/2018 5:58 PM