7

#include<iostream>
#include<thread>
#include<mutex>
#include<ctime>

std::mutex block;


// Проверяем все элементы по порядку
void Max1(int **mat, int m, int n) {
	int max = mat[0][0];
	for (size_t i = 0; i < m; i++)
		for (size_t j = 0; j < n; j++)
			if (max < mat[i][j])
				max = mat[i][j];
	std::cout << "\t Max element =" << max;
}

// Проверяем все элементы строки
void Max2(int *mat, int n, int &temp) {
	int t = mat[0];
	for (size_t i = 0; i < n; i++)
		if (t < mat[i])
			t = mat[i];
	block.lock();
	std::cout << "  "<< t <<"  ";
	block.unlock();
	temp = t;
}

void main() {
	srand(time(NULL));
	unsigned int start_time, end_time;

	// Создание, заполнение и вывод матрицы
	int m, n;
	std::cout << "\tEnter M and N\n"; std::cin >> m >> n;
	int **mat = new int *[m];
	for (size_t i = 0; i < m; i++)
		mat[i] = new int[n];
	for (size_t i = 0; i < m; i++) {
		for (size_t j = 0; j < n; j++) {
			mat[i][j] = rand() % 100;
			std::cout << mat[i][j] << " ";
		}
		std::cout << std::endl;
	}

	// Выполнение задачи в 1 поток
	std::cout << "\n\tV 1:\n";
	start_time = clock();
	std::thread t1(Max1, std::ref(mat), m, n);
	t1.join();
	end_time = clock();
	std::cout << "\n\tThread work time = " << end_time - start_time << " milliseconds\n\n";
	std::cout << "\n\n";


	// Разбиение на m потоков
	std::cout << "\n\tV 2:";
	std::thread *threads = new std::thread[m];
	int T = 0;
	start_time = clock();
	for (size_t i = 0; i < m; i++)
		threads[i] = std::thread(Max2, mat[i], n, std::ref(T));
	for (size_t i = 0; i < m; i++)
		threads[i].join();

	end_time = clock();
	std::cout << "\n\tMax element = " << T;
	std::cout << "\n\tThread work time = " << end_time - start_time << " milliseconds\n\n";

	system("pause");
}