Serialize and Deserialize Binary Tree

Problem Description

Design an algorithm to serialize and deserialize a binary tree.

Implement:

• serialize(root) that converts a tree to a string.
• deserialize(data) that converts the string back to the original tree.

In this live problem, your solution is validated using a round-trip check:

1. Serialize the input tree.
2. Deserialize it.
3. Return the rebuilt tree in level-order list format.

Examples

Example 1:

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

Example 2:

Input: root = []
Output: []

Constraints

• The number of nodes in the tree is in the range [0, 10^4].
• -1000 <= Node.val <= 1000

Hint

Preorder traversal with explicit null markers is a common reliable approach.