# 384. Shuffle an Array (Medium)

https://leetcode.com/problems/shuffle-an-array/

Shuffle a set of numbers without duplicates.

Example:

```// Init an array with set 1, 2, and 3.
int[] nums = {1,2,3};
Solution solution = new Solution(nums);

// Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must equally likely to be returned.
solution.shuffle();

// Resets the array back to its original configuration [1,2,3].
solution.reset();

// Returns the random shuffling of array [1,2,3].
solution.shuffle();
```

## Solutions

``````class Solution {

int[] nums;
int[] numsCopy;

public Solution(int[] nums) {
this.nums = nums;

numsCopy = new int[nums.length];

reset();
}

public int[] reset() {
System.arraycopy(nums, 0, numsCopy, 0, nums.length);

return nums;
}

private void swap(int[] nums, int x, int y) {
int tmp = nums[x];
nums[x] = nums[y];
nums[y] = tmp;
}

public int[] shuffle() {
for (int i = numsCopy.length - 1; i >= 0; i--) {
int randIdx = (int) (Math.random() * (i + 1));

swap(numsCopy, randIdx, i);
}

return numsCopy;
}
}
``````