package stack_queue; import java.util.LinkedList; import java.util.Queue; /** * @Author: wei1 * @Date: Create in 2018/11/21 16:21 * @Description: * 实现一种狗猫队列的结构, 要求如下: 用户可以调用add方法将cat类或dog类的 * 实例放入队列中; 用户可以调用pollAll方法, 将队列中所有的实例按照进队列 * 的先后顺序依次弹出; 用户可以调用pollDog方法, 将队列中dog类的实例按照 * 进队列的先后顺序依次弹出; 用户可以调用pollCat方法, 将队列中cat类的实 * 例按照进队列的先后顺序依次弹出; 用户可以调用isEmpty方法, 检查队列中是 * 否还有dog或cat的实例; 用户可以调用isDogEmpty方法, 检查队列中是否有dog * 类的实例; 用户可以调用isCatEmpty方法, 检查队列中是否有cat类的实例。 */ public class DogCatQueue { public static class Pet { private String type; public Pet(String type) { this.type = type; } public String getPetType() { return this.type; } } public static class Dog extends Pet { public Dog() { super("dog"); } } public static class Cat extends Pet { public Cat() { super("cat"); } } public static class PetEnterQueue { private Pet pet; private long count; public PetEnterQueue(Pet pet, long count) { this.pet = pet; this.count = count; } public Pet getPet() { return this.pet; } public long getCount() { return this.count; } public String getEnterPetType() { return this.pet.getPetType(); } } public static class DogCatQueueIn { private Queue dogQ; private Queue catQ; private long count; public DogCatQueueIn() { this.dogQ = new LinkedList(); this.catQ = new LinkedList(); this.count = 0; } public void add(Pet pet) { if (pet.getPetType().equals("dog")) { this.dogQ.add(new PetEnterQueue(pet, this.count++)); } else if (pet.getPetType().equals("cat")) { this.catQ.add(new PetEnterQueue(pet, this.count++)); } else { throw new RuntimeException("err, not dog or cat"); } } public Pet pollAll() { if (!this.dogQ.isEmpty() && !this.catQ.isEmpty()) { if (this.dogQ.peek().getCount() < this.catQ.peek().getCount()) { return this.dogQ.poll().getPet(); } else { return this.catQ.poll().getPet(); } } else if (!this.dogQ.isEmpty()) { return this.dogQ.poll().getPet(); } else if (!this.catQ.isEmpty()) { return this.catQ.poll().getPet(); } else { throw new RuntimeException("err, queue is empty!"); } } public Dog pollDog() { if (!this.isDogQueueEmpty()) { return (Dog) this.dogQ.poll().getPet(); } else { throw new RuntimeException("Dog queue is empty!"); } } public Cat pollCat() { if (!this.isCatQueueEmpty()) { return (Cat) this.catQ.poll().getPet(); } else { throw new RuntimeException("Cat queue is empty!"); } } public boolean isEmpty() { return this.dogQ.isEmpty() && this.catQ.isEmpty(); } public boolean isDogQueueEmpty() { return this.dogQ.isEmpty(); } public boolean isCatQueueEmpty() { return this.catQ.isEmpty(); } } public static void main(String[] args) { DogCatQueueIn test = new DogCatQueueIn(); Pet dog1 = new Dog(); Pet cat1 = new Cat(); Pet dog2 = new Dog(); Pet cat2 = new Cat(); Pet dog3 = new Dog(); Pet cat3 = new Cat(); test.add(dog1); test.add(cat1); test.add(dog2); test.add(cat2); test.add(dog3); test.add(cat3); test.add(dog1); test.add(cat1); test.add(dog2); test.add(cat2); test.add(dog3); test.add(cat3); test.add(dog1); test.add(cat1); test.add(dog2); test.add(cat2); test.add(dog3); test.add(cat3); while (!test.isDogQueueEmpty()) { System.out.println(test.pollDog().getPetType()); } while (!test.isEmpty()) { System.out.println(test.pollAll().getPetType()); } } }