LowestCommonAncestor

Published at 2021-11-21

# 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':
        if p.val < root.val and q.val < root.val:
            return self.lowestCommonAncestor(root.left, p, q)
        elif p.val > root.val and q.val > root.val:
            return self.lowestCommonAncestor(root.right, p, q)
        else:
            return root

        # p랑 q가 둘다 현재노드보다 작다면 왼쪽탐색. 둘다 크면 오른쪽 탐색
        # 위 두조건에 안걸린다면 현재 노드가 알맞다는 뜻