Inorder successor of binary search tree - need to compile.

InorderSuccessor_needCompile.cs

using System;

class Solution
{
  class Node
  {
    public int value;
    public Node left;
    public Node right;
    public Node parent;
  }
  
  // given 5, find 9
  // test case 2: given node 14
  // test case 3: give node 25
  // test case 4: given node 9 
  // test case 5: given node 20 
  // test case 6: given node 11
  // time complexity - BST O(logN) - O(N) - space - linked list O(N) 
  static Node findInOrderSuccessor(Node inputNode)
  {
    // your code goes here
    if(inputNode == null)
    {
      return null; // ? 
    }
       
    // assume that node at least has one child 
    bool hasRightChild = inputNode.right != null; // false, false 
       
    if(hasRightChild)
       {
         return getMinimum(inputNode.right); // ? node 12 , return node 11
       }
    else 
       {
         // find parent node which is bigger than givenNode
         var givenValue = inputNode.value; // 5, 14, 25
         var iterate = inputNode; 
         while(iterate.parent != null && iterate.parent.value < givenValue)  // 9 > 5, 12 < 14, 20 > 14
         {
           iterate = iterate.parent; // node 12, node 9
         }
         
         return iterate.parent; 
      /*
         // uttermost parent node, iterate node has no parent node
         if(iterate.parent != null && iterate.parent.value > givenValue)
         {
           return iterate.parent; // return node 9 , return node 20, return 12
         }
         else 
         {
           return null; // return null, 
         }
         */
       }     
  }
       
  private static Node getMinimum(Node root)
       {
         var minimum = root; // node 12
         while(minimum.left != null) 
         {
           minimum = minimum.left; // node 11
         }
         
         return minimum; // return node 11
       }

  static void Main(string[] args)
  {
    // test findInOrderSuccessor here
  }
}