Week 10 example

Program.java

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.PriorityQueue;

class WaitTimeComparator implements Comparator<Customer> {
    @Override
    public int compare(Customer c1, Customer c2) {
//        if (c1.waitTime > c2.waitTime) {
//            return -1;
//        } else if (c1.waitTime == c2.waitTime) {
//            return 0;
//        } else {
//            return 1;
//        }
        return c2.waitTime - c1.waitTime;
    }
}

class Customer {
    public final int waitTime;
    public final String name;

    Customer(int waitTime, String name) {
        this.waitTime = waitTime;
        this.name = name;
    }

    public static PriorityQueue<Customer> prioritise(ArrayList<Customer> customers) {
        PriorityQueue<Customer> result = new PriorityQueue<>(new WaitTimeComparator());
        for (Customer customer : customers) {
            result.add(customer);
        }
        return result;
    }
}

public class Program {
    public static void main(String[] args) {
        ArrayList<Customer> customers = new ArrayList<>();
        customers.add(new Customer(10, "Bob"));
        customers.add(new Customer(2, "Alice"));
        customers.add(new Customer(1337, "Eve"));

        PriorityQueue<Customer> prioritised = Customer.prioritise(customers);
        while (!prioritised.isEmpty()) {
            Customer next = prioritised.remove();
            System.out.println("Now serving " + next.name);
        }
    }
}