我需要随机洗牌以下数组:

int[] solutionArray = {1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1};

有什么函数可以做到吗?


当前回答

无随机解:

   static void randomArrTimest(int[] some){
        long startTime = System.currentTimeMillis();
        for (int i = 0; i < some.length; i++) {
            long indexToSwap = startTime%(i+1);
            long tmp = some[(int) indexToSwap];
            some[(int) indexToSwap] = some[i];
            some[i] = (int) tmp;
        }
        System.out.println(Arrays.toString(some));
    }

其他回答

类似的情况没有使用swap b

    Random r = new Random();
    int n = solutionArray.length;
    List<Integer> arr =  Arrays.stream(solutionArray)
                               .boxed()
                               .collect(Collectors.toList());
    for (int i = 0; i < n-1; i++) {
        solutionArray[i] = arr.remove(r.nextInt(arr.size())); // randomize based on size
    }
    solutionArray[n-1] = arr.get(0);

你现在可以使用java 8了:

Collections.addAll(list, arr);
Collections.shuffle(list);
cardsList.toArray(arr);

下面是使用集合的完整解决方案。洗牌的方法:

public static void shuffleArray(int[] array) {
  List<Integer> list = new ArrayList<>();
  for (int i : array) {
    list.add(i);
  }

  Collections.shuffle(list);

  for (int i = 0; i < list.size(); i++) {
    array[i] = list.get(i);
  }    
}

请注意,由于Java无法在int[]和Integer[]之间平滑转换(因此int[]和List<Integer>),它受到了影响。

你应该使用Collections.shuffle()。但是,不能直接操作原始类型数组,因此需要创建包装器类。

试试这个。

public static void shuffle(int[] array) {
    Collections.shuffle(new AbstractList<Integer>() {
        @Override public Integer get(int index) { return array[index]; }
        @Override public int size() { return array.length; }
        @Override public Integer set(int index, Integer element) {
            int result = array[index];
            array[index] = element;
            return result;
        }
    });
}

And

int[] solutionArray = {1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1};
shuffle(solutionArray);
System.out.println(Arrays.toString(solutionArray));

输出:

[3, 3, 4, 1, 6, 2, 2, 1, 5, 6, 5, 4]

最简单的解决方案,这种随机洗牌数组。

String location[] = {"delhi","banglore","mathura","lucknow","chandigarh","mumbai"};
int index;
String temp;
Random random = new Random();
for(int i=1;i<location.length;i++)
{
    index = random.nextInt(i+1);
    temp = location[index];
    location[index] = location[i];
    location[i] = temp;
    System.out.println("Location Based On Random Values :"+location[i]);
}