297\. Serialize and Deserialize Binary Tree

Hard

Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another computer environment.

Design an algorithm to serialize and deserialize a binary tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary tree can be serialized to a string and this string can be deserialized to the original tree structure.

**Clarification:** The input/output format is the same as _how LeetCode serializes a binary tree_. You do not necessarily need to follow this format, so please be creative and come up with different approaches yourself.

**Example 1:**

![](https://assets.leetcode.com/uploads/2020/09/15/serdeser.jpg)

**Input:** root = [1,2,3,null,null,4,5]

**Output:** [1,2,3,null,null,4,5] 

**Example 2:**

**Input:** root = []

**Output:** [] 

**Example 3:**

**Input:** root = [1]

**Output:** [1] 

**Example 4:**

**Input:** root = [1,2]

**Output:** [1,2] 

**Constraints:**

*   The number of nodes in the tree is in the range <code>[0, 10<sup>4</sup>]</code>.
*   `-1000 <= Node.val <= 1000`