Serialize and Deserialize Binary Tree in DSA Typescript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does it mean to serialize a binary tree?

Serialization means converting the binary tree into a string or list format that can be stored or transmitted easily, preserving the tree structure.

beginner

What is the purpose of deserialization in binary trees?

Deserialization means converting the serialized string or list back into the original binary tree structure with the same node values and connections.

beginner

Why do we use a special marker like 'null' or '#' during serialization?

We use a special marker to represent empty or missing child nodes so that the tree structure can be fully reconstructed during deserialization.

intermediate

Which tree traversal method is commonly used for serialization and why?

Preorder traversal is commonly used because it visits the root first, then left and right subtrees, allowing us to record the structure and values in order.

intermediate

What is the time complexity of serializing and deserializing a binary tree with n nodes?

Both serialization and deserialization take O(n) time because each node is visited once during the process.

What does the 'null' marker represent in serialized binary tree data?

A The root node

B A missing child node

C A leaf node

D A duplicate node

The 'null' marker shows where a child node is missing, helping to keep the tree structure intact.

Which traversal order is best suited for serializing a binary tree to preserve structure?

A Preorder

B Inorder

C Postorder

D Level order

Preorder traversal records the root before its children, making it easier to reconstruct the tree.

What is the main goal of deserializing a binary tree?

A To sort the tree nodes

B To convert a tree into a string

C To count the number of nodes

D To rebuild the original tree from serialized data

Deserialization rebuilds the original tree structure from the serialized string or list.

If a binary tree has 7 nodes, how many 'null' markers will appear in its serialized form?

A 8

B 14

C 6

D 7

A binary tree with n nodes has n+1 null pointers, so 7 nodes have 8 null markers.

What is the time complexity to serialize and deserialize a binary tree with n nodes?

A O(log n)

B O(n^2)

C O(n)

D O(1)

Both serialization and deserialization visit each node once, so the time complexity is O(n).

Explain how preorder traversal helps in serializing and deserializing a binary tree.

Think about the order nodes are saved and restored.

Describe the steps to deserialize a binary tree from a serialized string with null markers.

Focus on how recursion helps rebuild the tree.