12. The Matrix

package Uprajnenie;

import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

public class TheMatrix {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);


        int rows = scanner.nextInt();
        int cols = scanner.nextInt();
        scanner.nextLine(); // Consume newline

        char[][] matrix = new char[rows][cols];
        for (int i = 0; i < rows; i++) {
            String[] row = scanner.nextLine().split(" ");
            for (int j = 0; j < cols; j++) {
                matrix[i][j] = row[j].charAt(0);
            }
        }

        char fillChar = scanner.next().charAt(0);
        int startRow = scanner.nextInt();
        int startCol = scanner.nextInt();

        fillMatrix(matrix, fillChar, startRow, startCol);

        // Print the filled matrix
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                System.out.print(matrix[i][j]);
            }
            System.out.println();
        }
    }

    private static void fillMatrix(char[][] matrix, char fillChar, int startRow, int startCol) {
        char startChar = matrix[startRow][startCol];
        int rows = matrix.length;
        int cols = matrix[0].length;

        Queue<Integer> queue = new LinkedList<>();
        queue.add(startRow);
        queue.add(startCol);

        while (!queue.isEmpty()) {
            int row = queue.poll();
            int col = queue.poll();

            if (matrix[row][col] != startChar) {
                continue;
            }

            matrix[row][col] = fillChar;

            if (isValid(row - 1, col, rows, cols)) {
                queue.add(row - 1);
                queue.add(col);
            }
            if (isValid(row + 1, col, rows, cols)) {
                queue.add(row + 1);
                queue.add(col);
            }
            if (isValid(row, col - 1, rows, cols)) {
                queue.add(row);
                queue.add(col - 1);
            }
            if (isValid(row, col + 1, rows, cols)) {
                queue.add(row);
                queue.add(col + 1);
            }
        }
    }

    private static boolean isValid(int row, int col, int rows, int cols) {
        return row >= 0 && row < rows && col >= 0 && col < cols;
    }
}