94. Binary Tree Inorder Traversal

2019-07-27

94. Binary Tree Inorder Traversal

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

Example:

1
2
3
4
5
6
7
8
Input: [1,null,2,3]
   1
    \
     2
    /
   3

Output: [1,3,2]

Follow up: Recursive solution is trivial, could you do it iteratively?

Code：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def inorderTraversal(self, root: TreeNode) -> List[int]:
        res, stack = [], []
        while True:
            while root:
                stack.append(root)

                root = root.left
            if not stack:
                return res
            node = stack.pop()
            res.append(node.val)
            root = node.right
# 左边为空就取有节点继续
-->