230.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

# Author: Yu Zhou

# ****************
# Descrption:
# 230. Kth Smallest Element in a BST
# Given a binary search tree, write a function kthSmallest to find the kth smallest element in it.
# ****************

classSolution(object):
defkthSmallest(self, root, k):
"""
 :type root: TreeNode
 :type k: int
 :rtype: int
 """
self.k=k
self.res=0

defdfs(root):
# Edge/Condition
ifnotroot:
return0

dfs(root.left)
self.k-=1
ifself.k==0:
self.res=root.val
dfs(root.right)

dfs(root)
returnself.res