How to reorder an Array-CodePudding

I want to change the first and last index of every array, so the output in this scenario would be: [2,3,1], [9,4,6] [5,8,4].

Any help would be greatly appreciated!

static void Main(string[] args)
{
    int[][] array1 =
  {
       new []{1,3,2},
       new []{6,4,9},
       new []{4,8,5}
   };
    foreach (int i in Snail(array1))
    {
        Console.WriteLine(i);
    }
}


public static int[] Snail(int[][] array)
{
    List<int> snail = new List<int>();
    foreach (int[] list in array)
    {
        foreach (int i in list)
        {
          // how do I change place with first and last index
        }
    }

CodePudding user response：

You only need one loop since you know the exact two indices you want to operate on

foreach (int[] list in array)
{
    if (list.Length < 2) continue; //need 2 elements to swap

    int temp = list[0]; //head is stored temporarily
    list[0] = list[^1]; //swap happens
    list[^1] = temp; //now set tail as temp value (the original head)
}

Note that list[^1] is the same as saying list[list.Length - 1], both meaning the last element