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.

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.

Test Cases

Copy an input into the main harness and Run to verify

Input

root = [1,2,3,null,null,4,5]

Expected Output

[1,2,3,null,null,4,5]

Input

root = []

Expected Output

[]

Constraints

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

Hints

Hint 1 — click to reveal

Pre-order with explicit null markers captures structure uniquely.

Hint 2 — click to reveal

Deserialize with a queue/iterator consuming tokens in the same order.

Java Compiler