0449. Serialize and Deserialize BST

https://leetcode.com/problems/serialize-and-deserialize-bst

Description

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

The encoded string should be as compact as possible.

Example 1:

**Input:** root = [2,1,3]
**Output:** [2,1,3]

Example 2:

**Input:** root = []
**Output:** []

Constraints:

• The number of nodes in the tree is in the range [0, 104].

• 0 <= Node.val <= 104

• The input tree is guaranteed to be a binary search tree.

ac