leetcode#94 Binary Tree Inorder Traversal

1. 문제

• https://leetcode.com/problems/binary-tree-inorder-traversal/

2. 나의 풀이

2-1. 재귀호출?

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution(object):
    def inorderTraversal(self, root):
        """
        :type root: TreeNode
        :rtype: List[int]
        """
        
        r = []
        
        def in_order(node, result):
            if node and node.left:
                in_order(node.left, result)
            if node:
                result.append(node.val)
            if node and node.right:
                in_order(node.right, result)
            
            return result
        
        return in_order(root, r)

3. 남의 풀이