Problem :

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


My Solution :

# 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):
"""
:type root: TreeNode
:rtype: List[int]
"""
ret = []
stack = []
curr = root
while stack or curr:
if curr:
stack.append(curr)
curr = curr.left
else:
curr = stack.pop()
ret.append(curr.val)
curr = curr.right
return ret


My Solution2 :

# 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):
"""
:type root: TreeNode
:rtype: List[int]
"""
ret = []

def inorder(node):
if node:
inorder(node.left)
ret.append(node.val)
inorder(node.right)

inorder(root)
return ret