MultidimensionalArrays - problem 7*

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

namespace _07.EqualNeighbors
{
    class Program
    {
        static int tempCount = 1;
        static bool[,] visited;

        static void Main(string[] args)
        {
            int[,] matrix = {
                                {1, 3, 2, 2, 2, 4},
                                {3, 3, 3, 2, 2, 4},
                                {4, 3, 1, 2, 3, 3},
                                {4, 3, 1, 3, 3, 1},
                                {4, 3, 3, 3, 1, 1}
                            };
            visited = new bool[matrix.GetLength(0), matrix.GetLength(1)];
            int bestCount = 0;
            int bestNumber = 0;


            for (int i = 0; i < matrix.GetLength(0); i++)
            {
                for (int j = 0; j < matrix.GetLength(1); j++)
                {
                    tempCount = 1;
                    CountLength(matrix, visited, i, j);
                    if (tempCount > bestCount)
                    {
                        bestCount = tempCount;
                        bestNumber = matrix[i, j];
                    }

                }
            }
            Console.WriteLine("The longest sequence is: {0}, the number is: {1}", bestCount, bestNumber);

        }

        static void CountLength(int[,] matrix, bool[,] visited, int startRow, int startCol)
        {
            int number = matrix[startRow, startCol];
            visited[startRow, startCol] = true;
            int i = startRow;
            int j = startCol;

            if (matrix[startRow, startCol] != number)
            {
                return;
            }

                if (CellIsValid(matrix, visited, number, i - 1, j))     //=== check UP
                {
                    tempCount++;
                    CountLength(matrix, visited, i - 1, j);
                }
                if (CellIsValid(matrix, visited, number, i, j + 1))     //=== check RIGHT
                {
                    tempCount++;
                    CountLength(matrix, visited, i, j + 1);
                }
                if (CellIsValid(matrix, visited, number, i + 1, j))     //=== check DOWN
                {
                    tempCount++;
                    CountLength(matrix, visited, i + 1, j);
                }
                if (CellIsValid(matrix, visited, number, i, j - 1))     //=== check LEFT
                {
                    tempCount++;
                    CountLength(matrix, visited, i, j - 1);
                }
        }

        private static bool CellIsValid(int[,] matrix, bool[,] visited, int number, int row, int col)
        {
            if (row >= 0 && row < matrix.GetLength(0) && col >=0 && col < matrix.GetLength(1))       //check if position is inside the matrix
            {
                if (visited[row, col] == false && matrix[row, col] == number)            //check if the cell has been visited or if the number is different
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            else
            {
                return false;
            }
        }
    }
}