#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 = 1 + rand() % 3;

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

	sleep(delay);
}

int main() 
{
	int total = 6; //tasks
	int levels = 2; //workers
	pid_t root = getpid();
	//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 determinist count 

		for (int i = 0; i < total; ++i)
		{
			if (i % worker_count == worker_id % worker_count) {
			std::cout << "[" << getpid() << "id=" << worker_id;
				random_tasks(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;
}