1.题目描述
给定一个二叉树,返回它的中序 遍历。
示例:
输入: [1,null,2,3]
1
\
2
/
3输出: [1,3,2]
2.解题思路
3.代码实现
# 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(self, root):
"""
:type root: TreeNode
:rtype: List[int]
"""
res=[]
stack=[]
if not root:
return res
while root or stack:
while root:
stack.append(root)
root=root.left
if stack:
root=stack.pop(-1)
res.append(root.val)
root=root.right
return res