Binary Tree Inorder Traversal

Code

O(N) : 28m Your runtime beats 64.49 % of python3 submissions.

class Solution:
    def inorderTraversal(self, root: TreeNode):
        stack = []
        result = []
        node = None
        while True:
            if node:
                stack.append(node)
                node = node.left
            elif stack:
                node = stack.pop()
                result.append(node.val)
                node = node.right
            else:
                break
        return result