Some. NET and SQL questions 2 (with answers)

1. The factorial of N to implement the algorithm

   Code        public static int N(int n)        {            if (n == 1)            { return 1; }            else            {                return n * N(n - 1);            }        }

2. Two sorted arrays are combined into a new array in order of size to implement the algorithm.

   Code   public static void Composite(int[] a, int[] b)        {            int[] newArray = new int[a.Length + b.Length];            int count = a.Length + b.Length;            int aIndex = 0;            int bIndex = 0;            for (int i = 0; i < count; i++)            {                if (aIndex >= i)                {                    newArray[i] = a[aIndex];                    continue;                }                if (bIndex >= i)                {                    newArray[i] = b[bIndex];                    continue;                }                if (a[aIndex] <= b[bIndex])                {                    newArray[i] = a[aIndex];                    aIndex++;                }                else                {                    newArray[i] = b[bIndex];                    bIndex++;                }                Console.WriteLine(newArray[i]);            }        }

3. Write all the combinations of 1, 2, 2, 4, 5, but 4 cannot be in 3rd bits, and 3 and 5 cannot be adjacent.

   Code   public static List<string> listStr = new List<string>();        public static void OutputConposition()        {            char[] arr = { '1', '2', '2', '3', '4', '5' };            string str = new string(arr);            Function(arr, 0, 5);        }        public static void Function(char[] c, int begin, int end)        {            if (begin == end)            {                string str = new string(c);                if (str[2] == '4')                { return; }                if (str.Contains("35") || str.Contains("53"))                { return; }                listStr.Add(str);                return;            }            for (int i = begin; i <= end; i++)            {                Swap(c, begin, i);                Function(c, i + 1, end);                Swap(c, begin, i);            }        }        public static void Swap(char[] arr, int a, int b)        {            char temp;            temp = arr[a];            arr[a] = arr[b];            arr[b] = temp;        }