297. Serialize and Deserialize Binary Tree.py

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None


class Codec:
    def serialize(self, root):
        """Encodes a tree to a single string.
        
        :type root: TreeNode
        :rtype: str
        """
        if not root:
            return '# '
        return str(root.val) + ' ' + self.serialize(root.left) + self.serialize(root.right)

    def deserialize(self, data):
        """Decodes your encoded data to tree.
        
        :type data: str
        :rtype: TreeNode
        """
        def des():
            val = next(it)
            if val == '#':
                return None
            node = TreeNode(int(val))
            node.left = des()
            node.right = des()
            return node
        it = iter(data.split())
        return des()


# Your Codec object will be instantiated and called as such:
# codec = Codec()
# codec.deserialize(codec.serialize(root))