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

For example:

Given binary tree {1,#,2,3},

比較簡單，就是轉化成中序遍歷就可以。訪問順序是中序遍歷左子樹。根節點，中序遍歷右子樹

Python編程的時候須要註意，要在返回單一數字的時候加上中括號【】，否則Python不知道這是一個list

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

class Solution:
    # @param root, a tree node
    # @return a list of integers
    def inorderTraversal(self, root):
        if root is None:
            return []
        elif root.left is None and root.right is None:
            return [root.val]
        else:
            return self.inorderTraversal(root.left)+[root.val]+self.inorderTraversal(root.right)

【LeetCode】【Python】Binary Tree Inorder Traversal