# DIY: Snapshot Array

Solve the interview question "Snapshot Array" in this lesson.

We'll cover the following

## Problem statement

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

• SnapshotArray(length): This property initializes a data structure with length number of indexes. Initially, the value at each index is 0.

• set(idx,val): This property sets the value at a given index idx to val.

• snap: This property takes no parameters and returns the snapid. snapid is the number of times that the snapshot function was called minus 1.

• get(idx,snapid) function returns the value at the index idx with the given snapid.

## Input

The input will be two integers, that is an index and a value. We can set the value of the index idx,using the setValue(idx,val) function.

snapshotArr = SnapshotArray(3)
snapshotArr.set(0,4)
snapshotArr.snap
snapshotArr.get(0,0)
snapshotArr.set(1,6)
snapshotArr.snap
snapshotArr.get(1,1)


## Output

The output will be an integer. We will receive an output by calling the get(idx,snapid) function. For example, we will get the following output after calling the get(idx,snapid) function on the input given above:

4
6


## Coding exercise

Using the skeleton code given below, you need to implement the SnapshotArray class with the set(idx,val), snap, and  get(idx,snapid) functions:

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