Connected Cell In a Grid - using queue - write in 20 minutes

ConnectedCellInaGridQueue2.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConnectedCellInaGridQueue2
{
    class Program
    {
        static void Main(string[] args)
        {
            int row = Convert.ToInt32(Console.ReadLine());
            int col = Convert.ToInt32(Console.ReadLine());

            int[,] arr = new int[row, col];

            for (int i = 0; i < row; i++)
            {
                string s = Console.ReadLine().ToString();

                int j = 0;
                foreach (char c in s)
                {
                    if (c == '0' || c == '1')
                    {
                        arr[i, j++] = c - '0'; 
                    }
                }
            }

            Console.WriteLine(getMaxRegion(arr)); 
        }

        public static int getMaxRegion(int[,] arr)
        {
            int row = arr.GetLength(0);
            int col = arr.GetLength(1); 

            int Max = Int32.MinValue; 
            for(int i=0; i< row; i++)
                for (int j = 0; j < col; j++)
                {
                    int val = getCount(arr, i, j);
                    if (val > Max)
                        Max = val; 
                }

            return Max; 
        }

        private static int getCount(int[,] arr, int posX, int posY)
        {
            int row = arr.GetLength(0);
            int col = arr.GetLength(1);

            if (arr[posX, posY] != 1)
                return 0; 

            
            Queue<int> queue = new Queue<int>(); 
            int key = posX * 10 + posY;
            queue.Enqueue(key);

            int count = 0; 
            while (queue.Count > 0)
            {
                int tmpKey = queue.Dequeue();
                int tmpX = tmpKey / 10;
                int tmpY = tmpKey % 10;

                count++; 
                arr[tmpX, tmpY] = 2; 

                for(int dr=-1; dr<=1; dr++)
                    for (int dc = -1; dc <= 1; dc++)
                    {
                        int nX = tmpX + dr;
                        int nY = tmpY + dc;

                        if (isInRange(nX, nY, row, col) && arr[nX, nY] == 1)
                        {
                            arr[nX, nY] = 2;  // make sure that no node will be added twice
                            queue.Enqueue(nX * 10 + nY); 
                        }
                    }

            }

            return count; 
        }

        private static bool isInRange(int nX, int nY, int row, int col)
        {
            if (nX >= 0 && nX < row && nY >= 0 && nY < col)
                return true;
            else
                return false; 
        }
    }
}