面试会遇到的几个小程序

面试会遇到的几个小程序：

1.有数列如下：1，1，2，3，5，8，13，。。。，请第N位？（请用两种方法得到第N位是多少，并可查询任意一位是多少）

        //斐波那契数
        private static List<long> GetNum(long n)
        {
            long a = 1, b = 1, num = 0;
            List<long> resultArry = new List<long>();
            try
            {
                for (int i = 0; i < n; i++)
                {
                    num = a + b;
                    a = b;
                    b = num;
                    resultArry.Add(num);
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            return resultArry;
        }

　　

static long i = 0, j = 1, result = 0;
        static List<long> resultArry = new List<long>();
        private static long ReturnNum(long n)
        {
            if (n <= 2)
            {
                result = i + j;
            }
            else
            {
                result = ReturnNum(n - 1) + ReturnNum(n - 2);
            }

            if (!resultArry.Contains(result))
            {
                resultArry.Add(result);
            }
            return result;
        }

　　

static void Main(string[] args)
        {
            //方法一：
            List<long> resultArry = GetNum(10);
            foreach (long result in resultArry)
            {
                 Console.Write(result+",");
            }

             //方法二
            //ReturnNum(10);
            //resultArry.Insert(0, 1);
            //foreach (long result in resultArry)
           // {
            //      Console.Write(result+",");
            //}

             Console.Read();
        }