094.binary-tree-inorder-traversal

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


For example:
Given binary tree [1,null,2,3],

   1
    \
     2
    /
   3



return [1,3,2].


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

# 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 = [], [(1, root)]
        while stack:
            p = stack.pop()
            if not p[1]: continue
            stack.extend([(1, p[1].right), (0, p[1]), (1, p[1].left)]) if p[0] != 0 else res.append(p[1].val)
        return res