[Leetcode]@python 94. Binary Tree Inorder Traversal

题目链接

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

题目原文

Given a binary tree, return the inorder traversal of its nodes' values.

For example:
Given binary tree {1,#,2,3},

return [1,3,2].

题目大意

中序遍历一棵二叉树

解题思路

递归求解，先遍历左子树，再遍历根节点，最后遍历右子树

代码

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def inorderTraversal_re(self, root, inorder):
        if not root:
            return inorder
        inorder = self.inorderTraversal_re(root.left, inorder)
        inorder.append(root.val)
        inorder = self.inorderTraversal_re(root.right, inorder)
        return inorder

    def inorderTraversal(self, root):
        """
        :type root: TreeNode
        :rtype: List[int]
        """
        return self.inorderTraversal_re(root, [])