[LeetCode 384] Shuffle an Array

class Solution {
    int[] originNums;

    public Solution(int[] nums) {
        originNums = new int[nums.length];
        for (int i = 0; i < nums.length; i++) {
            originNums[i] = nums[i];
        }
    }
    
    /** Resets the array to its original configuration and return it. */
    public int[] reset() {
        return originNums;
    }
    
    /** Returns a random shuffling of the array. */
    public int[] shuffle() {
        int[] shuffleNums = new int[originNums.length];
        for (int i = 0; i < originNums.length; i++) {
            shuffleNums[i] = originNums[i];
        }
        
        for (int i = 0; i < shuffleNums.length; i++) {
            Random rand = new Random ();
            int randomIndex = rand.nextInt (shuffleNums.length - 1 - i + 1) + i;
            int temp = shuffleNums[randomIndex];
            shuffleNums[randomIndex] = shuffleNums[i];
            shuffleNums[i] = temp;
        }
        
        return shuffleNums;
    }
}

/**
 * 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();
 */