05. Blur Filter

using System;
using System.IO;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
#if DEBUG
        Console.SetIn(new StreamReader("../../../input.txt"));
#endif
        int blurAmount = int.Parse(Console.ReadLine());

        int[] dimensions = Console.ReadLine()
            .Split()
            .Select(int.Parse)
            .ToArray();

        long[,] pixelMatrix = ReadMatrix(dimensions);

        int[] target = Console.ReadLine()
            .Split()
            .Select(int.Parse)
            .ToArray();

        BlurMatrix(blurAmount, dimensions, pixelMatrix, target);
        PrintMatrix(pixelMatrix, dimensions);
    }

    private static long[,] ReadMatrix(int[] dimensions)
    {
        var pixelMatrix = new long[dimensions[0], dimensions[1]];

        for (int row = 0; row < dimensions[0]; row++)
        {
            int[] values = Console.ReadLine()
            .Split()
            .Select(int.Parse)
            .ToArray();

            for (int col = 0; col < dimensions[1]; col++)
                pixelMatrix[row, col] = values[col];
        }

        return pixelMatrix;
    }

    private static void PrintMatrix(long[,] pixelMatrix, int[] dimensions)
    {
        for (int row = 0; row < dimensions[0]; row++)
        {
            for (int col = 0; col < dimensions[1]; col++)
                Console.Write(pixelMatrix[row, col] + " ");
            Console.WriteLine();
        }
    }

    private static void BlurMatrix(int blurAmount, int[] dimensions, long[,] pixelMatrix, int[] target)
    {
        int targetRow = target[0];
        int targetCol = target[1];

        pixelMatrix[targetRow, targetCol] += blurAmount;

        if (targetRow + 1 < dimensions[0])
            pixelMatrix[targetRow + 1, targetCol] += blurAmount;

        if (targetRow + 1 < dimensions[0] && targetCol + 1 < dimensions[1])
            pixelMatrix[targetRow + 1, targetCol + 1] += blurAmount;

        if (targetRow + 1 < dimensions[0] && targetCol - 1 >= 0)
            pixelMatrix[targetRow + 1, targetCol - 1] += blurAmount;

        if (targetCol + 1 < dimensions[1])
            pixelMatrix[targetRow, targetCol + 1] += blurAmount;

        if (targetCol - 1 >= 0)
            pixelMatrix[targetRow, targetCol - 1] += blurAmount;

        if (targetRow - 1 >= 0)
            pixelMatrix[targetRow - 1, targetCol] += blurAmount;

        if (targetRow - 1 >= 0 && targetCol + 1 < dimensions[1])
            pixelMatrix[targetRow - 1, targetCol + 1] += blurAmount;

        if (targetRow - 1 >= 0 && targetCol - 1 >= 0)
            pixelMatrix[targetRow - 1, targetCol - 1] += blurAmount;
    }
}