128. Serialize and Deserialize Binary Tree

PRO

Hard

Topics

Companies

Helpful tools to learn & understand

Watch key transitions, pointers, and variables update step-by-step.

Open

Read clean, documented implementations across multiple patterns.

View Code

Sketch diagrams on an infinite canvas and draft notes directly inline.

Draw

Input: root = [1,2,3,null,null,4,5]

Output: [1,2,3,null,null,4,5]

Explanation: The input tree is serialized and then deserialized, resulting in the same tree structure.

Input: root = []

Output: []

Explanation: An empty tree is serialized to an empty string, which is then deserialized back into an empty tree.

Input: root = [1]

Output: [1]

Explanation: A single-node tree is serialized and deserialized correctly.

Time Complexity

O(n)

Space Complexity

O(n)