Solution: Snapshot Array

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 $n-1$ ...