View difference between Paste ID: gNcuPQe9 and DTR0hxxA

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 
 namespace MatrixShuffle
 {
     class Program
     {
         static void Main(string[] args)
         {
             int matrixSize = int.Parse(Console.ReadLine());
             string input = Console.ReadLine();
             char[,] matrix = new char[matrixSize, matrixSize];
             int row = 0;
             int col = 0;
             string direction = "right";
             int matrixLength = matrixSize * matrixSize;
 
 
                 for (int i = 0; i < matrixLength; i++)
                 {
                     if (direction == "right" && (col > matrixSize - 1 || matrix[row, col] != default(char)))
                     {
                         direction = "down";
                         col--;
                         row++;
                     }
                     if (direction == "down" && (row > matrixSize - 1 || matrix[row, col] != default(char)))
                     {
                         direction = "left";
                         row--;
                         col--;
                     }
                     if (direction == "left" && (col < 0 || matrix[row, col] != default(char)))
                     {
                         direction = "up";
                         col++;
                         row--;
                     }
 
                     if (direction == "up" && (row < 0 || matrix[row, col] != default(char)))
                     {
                         direction = "right";
                         row++;
                         col++;
                     }
                     if (i > input.Length - 1)
                     {
                         matrix[row, col] = ' ';
                     }
                     else
                     {
                         matrix[row, col] = input[i];
                     }
 
                     if (direction == "right")
                     {
                         col++;
                     }
                     if (direction == "down")
                     {
                         row++;
                     }
                     if (direction == "left")
                     {
                         col--;
                     }
                     if (direction == "up")
                     {
                         row--;
                     }
                 }
 
                 List<char> firstString = new List<char>();
                 List<char> secondString = new List<char>();
 
                 for (int rr = 0; rr < matrix.GetLength(0); rr++)
                 {
                     if (rr % 2 == 0)
                     {
                         for (int cc = 0; cc < matrix.GetLength(1); cc = cc + 2)
                         {
                             firstString.Add(matrix[rr, cc]);
                         }
                         for (int cc = 1; cc < matrix.GetLength(1); cc = cc + 2)
                         {
                             secondString.Add(matrix[rr, cc]);
                         }
                     }
                     else
                     {
                         for (int cc = 0; cc < matrix.GetLength(1); cc = cc + 2)
                         {
                             secondString.Add(matrix[rr, cc]);
                         }
                         for (int cc = 1; cc < matrix.GetLength(1); cc = cc + 2)
                         {
                             firstString.Add(matrix[rr, cc]);
                         }
                     }
                 }
 
                 bool isPalindrome = false;
 
                 string convertFirstString = new string(firstString.ToArray());
                 string convertSecondString = new string(secondString.ToArray());
 
                 string straightInput = convertFirstString + convertSecondString;
                 string straightInputToLower = straightInput.ToLower();
                 //var a = straightInputToLower.ToCharArray();
                 //Array.Reverse(a);
 
                 var original = straightInputToLower;
                 var reversed = new string(original.ToCharArray().Reverse().ToArray());
 
                 if (original == reversed)
                 {
                     isPalindrome = true;
                 }
 
                 if (isPalindrome)
                 {
                     Console.WriteLine("<div style='background-color:#4FE000'>" + straightInput + "</div>");
                 }
                 else
                 {
                     Console.WriteLine("<div style='background-color:#E0000F'>" + straightInput + "</div>");
                 }
         }
     }
 }