题目链接

https://leetcode.cn/problems/search-in-a-binary-search-tree/

代码

递归法

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def searchBST(self, root: Optional[TreeNode], val: int) -> Optional[TreeNode]:
        if not root or root.val == val:
            return root
        if root.val < val:
            result = self.searchBST(root.right, val)
        if root.val > val:
            result = self.searchBST(root.left, val)
        return result

迭代

class Solution:
    def searchBST(self, root: Optional[TreeNode], val: int) -> Optional[TreeNode]:
        while root:
            if root.val < val: root = root.right
            elif root.val > val: root = root.left
            else: return root