@Test
    public void test1(){
   
        //制造一个长度为N的符合题意的数组
        int N=11;
        int[] array=new int[N];
        for (int i =0 ; i <((N-1)/2) ; i++) {
   
            array[i]=i+1;
            array[i+5]=i+1;
        }
        Random random = new Random();
        int i = random.nextInt(N - 2);
        array[N-1]=i+N;
        System.out.println(Arrays.toString(array));
        //找出多出来的那个
        int result=0;
        //将数组里面的数互相异或求得结果
        for (int j = 0; j <N ; j++) {
   
            result=result^array[j];
        }
        System.out.println(result);
    }