Solution: Snapshot Array

Explore how to implement a Snapshot Array that supports setting values, taking snapshots, and retrieving stored values by snapshot ID. Understand both naive and optimized approaches using custom data structures like nested dictionaries to efficiently save and access snapshots. Learn the time and space complexities involved and see a step-by-step solution to handle multiple snapshot operations effectively.

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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 $n - 1$ ...