Encode and Rebuild a Binary Tree

Design two functions for a binary tree: - `encode(root) -> string` - `decode(data) -> root` Each tree node contains an integer value and has up to two children. Your `encode` function should convert a binary tree into a string representation. Your `decode` function should reconstruct an equivalent binary tree from that string. Requirements: - The reconstructed tree must have the same structure and node values as the original tree. - The format may be any deterministic representation of your choice. - Empty children must be represented in a way that allows exact reconstruction. - You may assume node values fit in standard integer range. Explain the data format you use and implement both functions.