297. Serialize and Deserialize Binary Tree
https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
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.
Example:
You may serialize the following tree:
1
/ \
2 3
/ \
4 5
as "[1,2,3,null,null,4,5]"
Clarification: The above 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.
Note: Do not use class member/global/static variables to store states. Your serialize and deserialize algorithms should be stateless.
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Intuition
Any standard traversal in order, pre order, post order can be used. We choose in order for the solution - easy on recursion
Note -
- null indicator - any character which does not represent a string
- delimiter - any character to separate numbers which may be of multiple digits
On Deserialize - pickup a data structure which offers FIFO, and keep reducing the data structure size to avoid dealing with position pointers arithmetic - Queue is a good choice
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Time - O(n)
Space - O(n)
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