Shuffle an Array

Statement

Given an integer array nums, write an algorithm to shuffle the array randomly. All permutations of the array should be equally likely.

Implement three functions of the Solution class:

• Initializes the object with the integer array nums.
• Resets the array to its original configuration and returns it.
• Returns a random shuffling of the array.

Example

Sample input

[2, 4, 5]

Expected output

Permutation  |  Occurrences | Frequency
[2, 4, 5]    |    150 times | 16.67%
[2, 5, 4]    |    150 times | 16.67%
[4, 2, 5]    |    150 times | 16.67%
[4, 5, 2]    |    150 times | 16.67%
[5, 2, 4]    |    150 times | 16.67%
[5, 4, 2]    |    150 times | 16.67%

Ideally, each permutation of the array should have an equal chance of appearing. With an input array of $3$ elements, the number of possible permutations of size $3$ ...