[LeetCode] 230. Kth Smallest Element in a BST

Problem: https://leetcode.com/problems/kth-smallest-element-in-a-bst/

In-order traverse the BST until collected K elements.

# 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:
        
        def inorder(node):
            if node:
                yield from inorder(node.left)
                yield node.val
                yield from inorder(node.right)
        
        gen = inorder(root)
        return [next(gen) for _ in range(k)][-1]

Edited on 06/06/2021. Update the inorder traversal approach.