binser.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
        """
        lst = self.serializeRecursively(root)
        return str(lst)
    
    def serializeRecursively(self, root):
        ret = []
        if root is None:
            ret.append(None)
            return ret
        ret.append(root.val)
        lhs = self.serializeRecursively(root.left)
        ret.extend(lhs)
        rhs = self.serializeRecursively(root.right)
        ret.extend(rhs)
        return ret

    def deserialize(self, data):
        """Decodes your encoded data to tree.
        
        :type data: str
        :rtype: TreeNode
        """
        data = data.translate(None, "[ ]").split(",")
        return self.deserializeRecursively(data)
        
    def deserializeRecursively(self, data):
        val = data.pop(0)
        val = None
        if val is None:
            return val
        ret = TreeNode(val)
        ret.left = self.deserializeRecursively(data)
        ret.right = self.deserializeRecursively(data)
        return ret
        
        

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