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:
    # 返回对应节点TreeNode
    def KthNode(self, pRoot, k):
        # write code here
        if not pRoot: return 
        if k==0: return
        queue = []
        node = pRoot
        count=0
        while queue or node:
            while node:
                queue.append(node)
                node = node.left
            if queue:
                node = queue[-1]
                # mid print(node)
                count+=1
                if count==k:
                    return node
                queue.pop()
                node = node.right