using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        int [,] spiralMarix =  { 

             {1,    2,   3,  4,    5},

                         {6,    7,   8,  9,   10},

                          {11,  12,  13,  14,  15},

                          {16,  17,  18,  19,  20} };

        Console.WriteLine(string.Join(",", SpiralCopy(spiralMatrix)));

    }

    public static int[] SpiralCopy(int[,] inputMatrix)

    {

      var result = new List<int>();

      int rows = inputMatrix.Length;

      int cols = inputMatrix.GetUpperBound(0);

      int row = 0;

      int col = 0;

      while(row < rows || col < cols) {

        for(int i = col; i < cols;i++)

          result.Add(inputMatrix[row,i]);

        row++; // 1

        for(int i = row; i < rows;i++) {

          result.Add(inputMatrix[i, cols - 1]);

        }

        cols--; // 3

        for(int i = cols - 1; i >= col;i--) {

          result.Add(inputMatrix[rows - 1, i]);

        }

        rows--; // 3

        for(int i = rows - 1; i >= row;i--) {

          result.Add(inputMatrix[i, col]);

        }

        col++;

      }

      return result.ToArray();

    }

}