import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Matrix300x300 {
    private static final int SIZE = 300;

    public static void main(String[] args) {
        int[][] matrix1 = generateMatrix(SIZE, SIZE);
        int[][] matrix2 = generateMatrix(SIZE, SIZE);

        long startTime = System.currentTimeMillis();
        int[][] resultSequential = multiplyMatricesSequential(matrix1, matrix2);
        long endTime = System.currentTimeMillis();
        long sequentialTime = endTime - startTime;

        startTime = System.currentTimeMillis();
        int[][] resultParallel = multiplyMatricesParallel(matrix1, matrix2);
        endTime = System.currentTimeMillis();
        long parallelTime = endTime - startTime;

        System.out.println("Sequential multiplication time: " + sequentialTime + " ms");
        System.out.println("Parallel multiplication time: " + parallelTime + " ms");
    }

    public static int[][] multiplyMatricesSequential(int[][] matrix1, int[][] matrix2) {
        int rows1 = matrix1.length;
        int columns1 = matrix1[0].length;
        int columns2 = matrix2[0].length;

        int[][] result = new int[rows1][columns2];

        for (int i = 0; i < rows1; i++) {
            for (int j = 0; j < columns2; j++) {
                for (int k = 0; k < columns1; k++) {
                    result[i][j] += matrix1[i][k] * matrix2[k][j];
                }
            }
        }

        return result;
    }

    public static int[][] multiplyMatricesParallel(int[][] matrix1, int[][] matrix2) {
        int rows1 = matrix1.length;
        int columns1 = matrix1[0].length;
        int columns2 = matrix2[0].length;

        int[][] result = new int[rows1][columns2];

        int numberOfThreads = 5; // Количество потоков
        ExecutorService executor = Executors.newFixedThreadPool(numberOfThreads);

        for (int i = 0; i < rows1; i++) {
            final int row = i;
            executor.execute(new Runnable() {
                @Override
                public void run() {
                    for (int j = 0; j < columns2; j++) {
                        for (int k = 0; k < columns1; k++) {
                            result[row][j] += matrix1[row][k] * matrix2[k][j];
                        }
                    }
                }
            });
        }

        executor.shutdown();
        while (!executor.isTerminated()) {
            // Ожидаем завершения всех потоков
        }

        return result;
    }

    public static int[][] generateMatrix(int rows, int columns) {
        int[][] matrix = new int[rows][columns];
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < columns; j++) {
                matrix[i][j] = (int) (Math.random() * 10);
            }
        }
        return matrix;
    }
}