题解 | #二叉搜索树的第k个结点#

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def __init__(self):
        self.count = 0
    # 返回对应节点TreeNode
    def KthNode(self, pRoot, k):
        # write code here
        if pRoot is None:
            return None
        ret = self.KthNode(pRoot.left, k)
        if ret is not None:
            return ret
        self.count += 1
#         print(k, self.count, pRoot.val)
        if self.count == k:
            return pRoot
        ret = self.KthNode(pRoot.right, k)
        if ret is not None:
            return ret