text: '''
  
  URL: https://leetcode.com/problems/search-in-a-binary-search-tree/
  
  Difficulty: Easy
  
  Description: Search in a Binary Search Tree
  
  Given the root node of a binary search tree (BST) and a value. You need to find the node in the BST that the node's value equals the given value. Return the subtree rooted with that node. If such node doesn't exist, you should return NULL.
  
  For example, 
  
  Given the tree:
          4
         / \
        2   7
       / \
      1   3
  
  And the value to search: 2
  You should return this subtree:
  
        2     
       / \   
      1   3
  In the example above, if we want to search the value 5, since there is no node with value 5, we should return NULL.
  
  Note that an empty tree is represented by NULL, therefore you would see the expected output (serialized tree format) as [], not null.
  
  '''
  
  # Definition for a binary tree node.
  
  
  class TreeNode:
      def __init__(self, val=0, left=None, right=None):
          self.val = val
          self.left = left
          self.right = right
  
  
  class Solution:
      def searchBST(self, root, val):
          node = root
  
          while node:
              if node.val == val:
                  return node
              elif node.val < val:
                  node = node.right
              else:
                  node = node.left
  
          return None
  