闲来无事，写个算法关于11000放在含有1001个元素。。。

1-1000放在含有1001个元素的数组中，只有唯一的一个元素值重复，其它均只出现
一次。每个数组元素只能访问一次，设计一个算法，将它找出来；不用辅助存储空
间，能否设计一个算法实现？

class Program
    {
        static void Main(string[] args)
        {
            int[] list = new int[101];
            Random r = new Random();
            int a= r.Next(1, 100);
            bool b = false;

            for (int i = 0; i < 101; i++)
            {

                if (!b)
                    list[i] = i + 1;
                else
                    list[i] = i;

                if (a == i + 1)
                {
                    list[i + 1] = a;

                    b = true;
                }

            }
            Console.WriteLine("The Random number : "+a.ToString());
            int left = 0, right = 100;

            int posion;

            posion = (left + right) / 2;
            int count = 0;

            while (right - left > 1)
            {

              
                if (list[posion] == posion)
                {
                    right = posion;
                }              
                else
                {
                    left = posion;
                  
                }
                posion = (left + right) / 2;

               ++count;
              
            }
       
            Console.WriteLine("At the " + count.ToString() + "th time found out the  Random number : " + list[posion].ToString() + " ; And his posion is " + posion.ToString());
            Console.Read();

        }
    }