Question

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.

This is atree question.

Idea(s)

  • DFS Solution using pre-order traversal
    • Encode: Iterate through binary tree using pre-order traversal adding the node value or “N” to indicate no child to a string with a delimiter in between
    • Decode: Split the string into an array on the delimiter, the order starts at the root, then goes from the left sub tree to the right subtree
    • Keep a counter that is the current array position
    • Stop building depth when you encounter an “N” (base case)
    • Building in preorder means creating the root, then recursively calling the dfs function to build the left and right sub trees in that order
    • Return the node

Solution