/// <summary>

        /// 两个从小到大排序好的int数组，合并后也返回一个从小到大排序好的数组，

        /// 包含两个数组中全部的元素

        /// </summary>

        /// <param name="a"></param>

        /// <param name="b"></param>

        /// <returns></returns>

        public static int[] MergeArray(int[] a, int[] b)

        {

            if( a == null || b== null )

                throw new NotSupportedException();

            int lena = a.Length;

            int lenb = b.Length;

            int[] c = new int[lena+lenb];

            int i, j, n;

            i = j = n = 0;

            while (i < lena && j < lenb)

            {

                if (a[i] < b[j])

                {

                    c[n++] = a[i++];

                }

                else if (a[i] > b[j])

                {

                    c[n++] = b[j++];

                 }

                else

                {

                    c[n++] = a[i++];

                    c[n++] = b[j++];                   

                }

            }

            if (i == lena)

            {

                while (j < lenb)

                    c[n++] = b[j++];

            }

            else

            {

                while (i < lena)

                    c[n++] = a[i++];

            }

            return c;

        }