384. Shuffle an Array

Given an integer array `nums`, design an algorithm to randomly shuffle the array.

Implement the `Solution` class:

• `Solution(int[] nums)` Initializes the object with the integer array nums.
• `int[] reset()` Resets the array to its original configuration and returns it.
• `int[] shuffle()` Returns a random shuffling of the array.

Example 1:

```Input
["Solution", "shuffle", "reset", "shuffle"]
[[[1, 2, 3]], [], [], []]
Output
[null, [3, 1, 2], [1, 2, 3], [1, 3, 2]]

Explanation
Solution solution = new Solution([1, 2, 3]);
solution.shuffle();    // Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must be equally likely to be returned. Example: return [3, 1, 2]
solution.reset();      // Resets the array back to its original configuration [1,2,3]. Return [1, 2, 3]
solution.shuffle();    // Returns the random shuffling of array [1,2,3]. Example: return [1, 3, 2]

```

Constraints:

• `1 <= nums.length <= 200`
• `-106 <= nums[i] <= 106`
• All the elements of `nums` are unique.
• At most `5 * 104` calls will be made to `reset` and `shuffle`.

384. Shuffle an Array
``````use rand::prelude::*;

struct Solution {
nums: Vec<i32>,
n: usize,
}

impl Solution {
fn new(nums: Vec<i32>) -> Self {
let n = nums.len();
Solution { rng, nums, n }
}

fn reset(&self) -> Vec<i32> {
self.nums.to_vec()
}

fn shuffle(&mut self) -> Vec<i32> {
let mut v = self.nums.to_vec();
let n = self.n;
for i in 0..n {
let j = self.rng.gen_range(i, n);
v.swap(i, j);
}
v
}
}
``````