static void Main(string[] args)
        {
            int[] A = { 1, 5, 6, 7, 12, 15, 55, 60 };
            int[] B = { 2, 4, 5, 6, 8, 9, 44, 44, 55, 56, 87 };
            IList<int> C = new List<int>();
            int AL = 0;
            int BL = 0;
            for (int i = 0; i < A.Length + B.Length - 1; i++)
            {
                if (AL >= A.Length)
                {
                    //如果A全部添加完毕 那么将剩下的B全部添加到C
                    if (BL < B.Length)
                    {
                        AddToList(C, B[BL]);
                        BL++;
                    }
                    else
                    {
                        break;
                    }
                }
                else if (BL >= B.Length)
                {
                    //如果B全部添加完毕 那么将剩下的A全部添加到C
                    if (AL < A.Length)
                    {
                        AddToList(C, A[AL]);
                        AL++;
                    }
                    else
                    {
                        break;
                    }
                }
                else
                {
                    if (A[AL] > B[BL])
                    {
                        AddToList(C, B[BL]);
                        BL++;
                    }
                    else if (A[AL] < B[BL])
                    {
                        AddToList(C, A[AL]);
                        AL++;
                    }
                    else
                    {
                       AddToList(C, B[BL]);
                        AL++;
                        BL++;
                    }
                }
            }
        }
        public static void AddToList(IList<int> C,int item)
        {
            if (C.LastOrDefault() < item)
            { C.Add(item); };
        }