Kth Smallest Element in a BST
Given a binary search tree, write a function kth Smallest to find the kth smallest element in it. Tags: Tree
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# 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 kthSmallest(self, root: TreeNode, k: int) -> int:
lst = []
self.helper(root, lst)
return lst[k - 1]
def helper(self, root, lst):
# perform an inorder traversal
if not root:
return
self.helper(root.left, lst)
lst.append(root.val)
self.helper(root.right, lst)