2025-08-24 16:54:22 +0000 UTC

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

class Codec:

    def serialize(self, root: Optional[TreeNode]) -> str:
        """Encodes a tree to a single string.
        """
        if root is None:
            return ""
        left, right = self.serialize(root.left), self.serialize(root.right)
        return f"{root.val}|{len(left)}|{left}{right}"

    def deserialize(self, data: str) -> Optional[TreeNode]:
        """Decodes your encoded data to tree.
        """
        if not data:
            return None
        val, left_len, rest = data.split("|", 2)
        root = TreeNode(int(val))
        root.left = self.deserialize(rest[:int(left_len)])
        root.right = self.deserialize(rest[int(left_len):])
        return root    

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