'''
Description: 
Autor: Au3C2
Date: 2021-03-23 17:12:55
LastEditors: Au3C2
LastEditTime: 2021-03-23 17:13:13
'''
class Solution:
    def inorderTraversal(self, root: TreeNode) -> List[int]:
        def dfs(root):
            if not root:
                return
            dfs(root.left)
            ans.append(root.val)
            dfs(root.right)

        ans = list()
        dfs(root)
        return ans

# 树，中等
# https://leetcode-cn.com/problems/binary-tree-inorder-traversal/