3454 假定已经获取题库中的试题号，并存放在数组arrayKT中。例如， int [] arrayKT={10, 13, 18, 19, 20, 22, 30, 31}。定义一个静态成员方法，该方法实现从上述数组中随机抽出n(n=arrayKT.Length-1)道考题, 并组成一个考题字符串。比如，随机从arrayKT中抽取n题组成考题字符串：“10, 13, 18, 20, 22, 30, 31”。要求，组成考题字符串中考题不重复，输出所有可能的字符串。

using System;

using System.Collections.Generic;

using System.Diagnostics.CodeAnalysis;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            int n = Convert.ToInt32(Console.ReadLine());

            string str = Console.ReadLine();

            string[] str1 = str.Split(' ');

            int[] number = new int[n];

            for (int i = 0; i < str1.Length; i++)

            {

                number[i] = Convert.ToInt32(str1[i]);

            }

            for (int i = number.Length - 1; i >= 0; i--)

            {

                for (int j = 0; j < number.Length; j++)

                {

                    if (number[i] != number[j])

                    {

                        Console.Write("{0} ", number[j]);

                    }

                }

                Console.WriteLine();

            }

        }

    }

}