LeetCode 384. 打乱数组

// 以数字集合 1, 2 和 3 初始化数组。

 int[] nums = {1,2,3}; 

Solution solution = new Solution(nums);  

// 打乱数组 [1,2,3] 并返回结果。任何 [1,2,3]的排列返回的概率应该相同。 

solution.shuffle(); 

 // 重设数组到它的初始状态[1,2,3]。 

solution.reset(); 

 // 随机返回数组[1,2,3]打乱后的结果。 

solution.shuffle();  

代码：

class Solution {

   private int[] nu;
   private int[] result;

    public Solution(int[] nums) {
        nu = nums;
        result = nu.clone();
    }

    /** Resets the array to its original configuration and return it. */
    public int[] reset() {
        result = nu.clone();
        return result;
    }

    /** Returns a random shuffling of the array. */
    public int[] shuffle() {
        Random random = new Random();
        for(int i=0;i<result.length;++i){
            int index = random.nextInt(result.length-i)+i;
            int tmp = result[i];
            result[i] = result[index];
            result[index] = tmp;
        }
        return result;
    }
}