Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.
According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has both v and w as descendants (where we allow a node to be a descendant of itself).”
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# 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 lowestCommonAncestor(self, root, p, q): """ :type root: TreeNode :type p: TreeNode :type q: TreeNode :rtype: TreeNode """ minNum = p.val if p.val <= q.val else q.val maxNum = p.val if p.val > q.val else q.val if maxNum < root.val: return self.lowestCommonAncestor(root.left, p, q) if minNum > root.val: return self.lowestCommonAncestor(root.right, p, q) return root.val