使用随机算法产生一个数，要求把1-1000W之间这些数全部生成

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无聊写个玩下

private static void createRandom() {

       Random random = new Random();
       long start = System.currentTimeMillis();

       int value = 1000000;

       ArrayList<Integer> list = new ArrayList<Integer>(value);
       for (int j = 1; j <= value; ++j) {
           list.add(j);
       }

       int index = 0;
       int count = 0;
       int tmp = 0;
       while (value > 0) {
           index = random.nextInt(value);
           // System.out.println(list.get(index));
           tmp = list.get(count + index);
           list.set(count + index, list.get(count));
           list.set(count, tmp);
           ++count;
           --value;
       }

       long end = System.currentTimeMillis();

       //----验证是否正确
       Collections.sort(list);
       int i = 0, size = list.size();
       for (; i < size; ++i) {
           if (list.get(i) != (i + 1))
               System.out.println(i + "error" + list.get(i));
       }
       //----验证是否正确

        System.out.println("creat3------");
       System.out.println("执行耗时 : " + (end - start) / 1000f + " 秒 ");
       System.out.println("集合大小为" + list.size());
   }

private static void createRandom4() {

       Random random = new Random();
       long start = System.currentTimeMillis();

       int value = 10000000;

       int[] list = new int[value];

       for (int j = 0; j < value; ++j) {
           list[j] = j+1;
       }

       int index = 0;
       int count = 0;
       int tmp = 0;
       while (value > 0) {
           index = random.nextInt(value);
//           System.out.println(list[count + index]);
           tmp = list[count + index];
           list[count + index] = list[count];
           list[count] = tmp;
           ++count;
           --value;
       }

       long end = System.currentTimeMillis();

       //----验证是否正确
//       Collections.sort(list);
//       int i = 0, size = list.length;
//       for (; i < size; ++i) {
//           if (list[i] != (i + 1))
//               System.out.println(i + "error" + list[i]);
//       }
       //----验证是否正确

       System.out.println("creat4------");
       System.out.println("执行耗时 : " + (end - start) / 1000f + " 秒 ");
       System.out.println("完了，集合大小为" + list.length);
   }

实际测试结果：
creat3------
执行耗时 : 5.169 秒
完了，集合大小为10000000
creat4------
执行耗时 : 0.729 秒
完了，集合大小为10000000

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