CC150:3.7

public class Animal {
 String type;
 Date arrive;
 String name;
}

public class Cats extends Animal{
	public Cats(String name){
		this.name=name;
		type="cats";
	}
}

public class Dogs extends Animal{
	public Dogs(String name){
		this.name=name;
		type="dogs";
	}
}

public class AnimalQueue{
	Linkedlist<Dog> dogs=new LinkedList<Dog>();
	LinkedList<Cat> cats=new LinkedList<Cat>();
	private int order=0;
	
	public void enqueue(Animal a){
		
		a.setOrder(order);
		order++;
		
		if(a instanceof Dog) 
			{dogs.addLast((Dog) a);
			
			}
		else (a instanceof Cat){
			cats.addLat((Cat)a);
			}
		public Animal dequeue(){
			if(dog.size()==0){
				return dequeueCats();
				}
			else(cats.size()==0){
				return dequeueDogs();
				}
			Dog dog=dogs.peek();
			Cat cat=cats.peek();
			
			if(dog.isOlderThan(at)){
				return dequeueDogs();
			}
			else{
				return dequeueCats();
			}
		
		public Dog dequeueDogs(){
			return dogs.poll();
			}
		
		public Cat dequeueCats(){
			return cats.poll();
		}
		
		}
				
		

	}
	
}