#include <iostream>
#include <unistd.h>
#include <sys/wait.h>
#include <vector>
#include <cstdlib>
#include <ctime>
#include <cmath>

void random_task(int id)
{
	srand(time(0));
	int delay = 3 + id;

	std::cout << "PID " << getpid()
	          << " PPID " << getppid()
	          << " task " << id
	          << " delay " << delay << "s\n";

	sleep(delay);
}

int main()
{
	int total = 9; //tasks
	int levels = 3; //workers
	pid_t root = getpid();
	std::cout << "Root PID: " << root << "\n";
	// Collective fork: children continue the loop
	for (int i = 0; i < levels; i++)
	{
		pid_t pid = fork();
	}
	// Workers: all processes except root
	if (getpid() != root)
	{
		int worker_id = getpid() % root;
		int worker_count = pow(2,levels)-1;   // small deterministic count

		for (int i = 0; i < total; ++i)
		{
			if (i % worker_count == worker_id % worker_count) {
				random_task(i);
			}
		}

		_exit(0);
	}

	// Root reaps all descendants
	int status;
	while (1)
	{
		pid_t finished = waitpid(-1, &status, 0);
		if (finished > 0)
		{
			std::cout << "Reaped PID " << finished << "\n";
			continue;
		}

		if (finished == -1 && errno == ECHILD)
			break;
	}

	return 0;
}