import java.util.concurrent.Semaphore;

public class DiningPhilosophers {
    static Fork[] forks = new Fork[6];
    static Philosopher[] philosophers = new Philosopher[6];

    public static void main(String[] args) {
        for(int i = 0; i < 6; i++) {
            forks[i] = new Fork();
        }
        for(int i = 0; i < 6; i++) {
            philosophers[i] = new Philosopher("P" + i, forks[i], forks[(i + 1) % 6]);

        }
        for(int i = 0; i < 6; i++) {
            philosophers[i].start();
        }
        for(int i = 0; i < 6; i++) {
            try {
                philosophers[i].join();
            }
            catch(InterruptedException e) {

            }
        }
    }
    static class Fork {
        Semaphore fork_semaphore = new Semaphore(1);
        void take_fork() {
            try {
                fork_semaphore.acquire();
            }
            catch (InterruptedException e) {

            }
        }
        void put_back_fork() {
            fork_semaphore.release();
        }
    }
    static class Philosopher extends Thread {
        String name;
        Fork left_fork;
        Fork right_fork;
        Philosopher(String _name, Fork _left, Fork _right) {
            name = _name;
            left_fork = _left;
            right_fork = _right;
        }
        @Override
        public void run() {
            left_fork.take_fork();
            right_fork.take_fork();
            eat();
            left_fork.put_back_fork();
            right_fork.put_back_fork();
            think();
        }
        void eat() {
            System.out.println(name + " is eating!");
            try {
                Thread.sleep(100);
            }
            catch (InterruptedException e) {

            }
        }
        void think() {
            System.out.println(name + " is thinking!");
        }
    }
}

/// 1 2 3 4 5 6