MaxSubMatrix

using System;

namespace _02.MaxSubMatrix
{
    class MaxSubMatrix
    {
        static void PrintSubMatrix(ref int[,] matrix, int bestRow, int bestCol, int size)
        {
            Console.WriteLine("The best submatrix with size {0} is", size);
            for (int i = 0; i < size; i++)
            {
                for (int k = 0; k < size; k++)
                {
                    Console.Write("{0,4}", matrix[bestRow + i, bestCol + k]);
                }
                Console.WriteLine();
            }
        }
        static void PrintMatrix(int[,] matrix)
        {
            for (int row = 0; row < matrix.GetLength(0); row++)
            {
                for (int col = 0; col < matrix.GetLength(1); col++)
                {
                    Console.Write("{0,4}",matrix[row,col]);
                }
                Console.WriteLine();
            }
        }
        static void Main(string[] args)
        {
            const int size = 3; // size of submatrix
            Console.Write("Enter N = ");
            int n = int.Parse(Console.ReadLine());
            Console.Write("Enter M = ");
            int m = int.Parse(Console.ReadLine());
            if (n<size||m<size)
            {
                Console.WriteLine("Wrong size of the matrix");
                return;
            }
            Console.WriteLine("The following random matrix is generated");
            int[,] matrix = new int[n, m];
            Random rand = new Random();
            for (int row = 0; row < matrix.GetLength(0); row++)
            {
                for (int col = 0; col < matrix.GetLength(1); col++)
                {
                    matrix[row, col] = rand.Next(0, 21);
                }
            }
            PrintMatrix(matrix);
            int maxSum = int.MinValue;
            int currentSum = 0;
            int startElementRow = 0;
            int startElementCol = 0;
            for (int row = 0; row < matrix.GetLength(0)-size+1; row++)
            {
                for (int col = 0; col < matrix.GetLength(1)-size+1; col++)
                {
                    for (int i = 0; i < size; i++)
                    {
                        for (int k = 0; k < size; k++)
                        {
                            currentSum += matrix[row + i, col + k];
                        }
                    }
                    if (currentSum>maxSum)
                    {
                        maxSum = currentSum;
                        startElementRow = row;
                        startElementCol = col;
                    }

                }
            }
            PrintSubMatrix(ref matrix, startElementRow, startElementCol, size);

        }
    }
}