Serialize and Deserialize Binary Tree [LeetCode 297]

BTEncDec.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
        """
        encode = []
        
        def traverseTree(curr: TreeNode):
            if curr:
                encode.append(str(curr.val))
                traverseTree(curr.left)
                traverseTree(curr.right)
            else:
                encode.append("X")
       
        traverseTree(root)
        
        return ",".join(encode)

    def deserialize(self, data):
        """Decodes your encoded data to tree.
        
        :type data: str
        :rtype: TreeNode
        """
        data =  data.split(",")
        
        def makeTree(idx):
            node = TreeNode(int(data[idx])) if data[idx] != "X" else None
            if node:
                node.left, idx = makeTree(idx+1)
                node.right, idx = makeTree(idx+1)
            return node, idx
        
        return makeTree(0)[0]
        

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