栈和队列_leetcode94

class Solution(object):
    def inorderTraversal(self, root):
        """
        :type root: TreeNode
        :rtype
        """

        res = []
        self.order(root, res)
        return res


    def order(self, root, res):
        if root:

            self.order(root.left, res)
            res.append(root.val)
            self.order(root.right, res)


class Solution2(object):
    def inorderTraversal(self, root):
        """
        :type root: TreeNode
        :rtype
        """

        class Command(object):
            def __init__(self, com, node):
                self.com = com
                self.node = node

        res = []
        stack = []

        if not root:
            return res
        stack.append(Command("go", root))

        while stack:
            com = stack.pop()

            if com.com == "print":
                res.append(com.node.val)
            else:
                if com.node.right:
                    stack.append(Command("go", com.node.right))
                stack.append(Command("print", com.node))
                if com.node.left:
                    stack.append(Command("go", com.node.left))

        return res