Serialize and Deserialize Binary Tree

Serialize and Deserialize Binary Tree is a Hard Data Structures and Algorithms interview problem you can solve, run and submit on Thita.ai. It belongs to the Tree Traversal Patterns (DFS & BFS) pattern, in the Serialization and Deserialization subpattern.

Problem statement

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:

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, 104].

- -1000 <= Node.val <= 1000

Topics and companies

Topics: String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree.

Reported in interviews at Facebook, Microsoft, Amazon, LinkedIn, Uber, Bloomberg, eBay, Quora, Qualtrics, Google, Oracle, Citadel and others.

How to practise Serialize and Deserialize Binary Tree on Thita.ai

Starter code is provided in C, C#, C++, Go, Java, JavaScript and Python. Your solution runs against 5 test cases for this problem, with the AI coach available for a hint when you are stuck rather than a finished answer. The reference solution runs in O(n), where n is the number of nodes in the tree. Both serialization and deserialization visit each node exactly once. time and O(n), for the queue used in level order traversal and for storing the output string/vector. space.

Open Serialize and Deserialize Binary Tree in the code editor, or read the Serialize and Deserialize Binary Tree editorial for a worked solution with its approach and complexity analysis.

Where Serialize and Deserialize Binary Tree sits in the DSA pattern sheet

Problems related to Serialize and Deserialize Binary Tree

Other problems that use the same Serialization and Deserialization and Tree Traversal Patterns (DFS & BFS) techniques:

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