Solution: Snapshot Array

Explore how to build a Snapshot Array data structure that supports setting values, taking snapshots, and retrieving historical values. Understand naive versus optimized approaches using nested dictionaries to achieve efficient time and space complexity for large datasets.

We'll cover the following...

Statement
Solution
- Naive approach
- Optimized approach using nested dictionaries

Statement

In this challenge, you have to implement a Snapshot Array with the following properties:

Constructor (length): This is the constructor and it initializes the data structure to hold the specified number of indexes.
Set Value (idx, val): This property sets the value at a given index idx to value val.
Snapshot(): This method takes no parameters and returns the Snap ID. Snap ID is the number of times that the snapshot function was called, less $1$ , as we start the count at $0$ . The first time this function is called, it saves a snapshot and returns $0$ . The $n^{th}$ time it is called, after saving the snapshot, it returns $n - 1$ ...