Given a binary search tree (BST), find the lowest common ancestor (LCA) node of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself).” (Problem)

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

    class Solution:
        def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode':      
            curr = root  
            while curr:
            
                if p.val>curr.val and q.val>curr.val:
                    curr = curr.right
                elif p.val<curr.val and q.val<curr.val:
                    curr = curr.left
                else:
                    return curr
							
			

Time Complexity => o(log(n))

Space Complexity => o(1)