text: # Time:  O(h)
  # Space: O(1)
  
  class TreeNode(object):
      def __init__(self, x):
          self.val = x
          self.left = None
          self.right = None
  
  
  class Solution(object):
      def searchBST(self, root, val):
          """
          :type root: TreeNode
          :type val: int
          :rtype: TreeNode
          """
          while root and val != root.val:
              if val < root.val:
                  root = root.left
              else:
                  root = root.right
          return root
  
  