# Time: O(N) where n the number of nodes in the input tree, as each node is checked once.
# Space: O(N)
'''

V = 5
       4
      / \x
     2   6
       x/ \
       5   7

    4
   / \
  2   5

    6
     \
      7

1) if root.val <= 4, continue to split root.right (left, right )
    1. root.right = left
    2. return root, right
2) else: continue to split root.left
    1. by the same logic
    2.

'''



# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None


class Solution(object):
    def splitBST(self, root, V):
        """
        :type root: TreeNode
        :type V: int
        :rtype: List[TreeNode]
        """
        if not root:
            return None, None
        elif root.val <= V:
            left, right = self.splitBST(root.right, V)
            root.right = left
            return root, right
        else:
            left, right = self.splitBST(root.left, V)
            root.left = right
            return left, root