# 0384 - Shuffle an Array

[0384 - Shuffle an Array](https://leetcode.com/problems/shuffle-an-array/)

Given an integer array nums, design an algorithm to randomly shuffle the array. All permutations of the array should be equally likely as a result of the shuffling.

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.

## Examples

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 in total will be made to reset and shuffle.

## Java Solution

```java
class Solution {
    
    private int[] nums;
    private int[] original;
    
    Random rand = new Random();

    public Solution(int[] nums) {
        this.nums = nums;
        original = nums.clone();
    }
    
    public int[] reset() {
        this.nums = original;
        original = original.clone();
        return original;
    }
    
    public int[] shuffle() {
        for(int i = 0; i < this.nums.length; i++) {
            swap(i, rand.nextInt(this.nums.length - i) + i);
        }
        return this.nums;
    }
    
    private void swap(int i, int j) {
        int temp = this.nums[i];
        this.nums[i] = this.nums[j];
        this.nums[j] = temp;        
    }
}

/**
 * Your Solution object will be instantiated and called as such:
 * Solution obj = new Solution(nums);
 * int[] param_1 = obj.reset();
 * int[] param_2 = obj.shuffle();
 */
```
