猫狗队列题目

2022-05-22 11:45 132阅读 0赞

源码下载链接:[https://github.com/huijuanl/AlgorithmLearning.git][https_github.com_huijuanl_AlgorithmLearning.git]

目录: ./[src][]/[main][]/[java][]/CatDogPackage/

实现一种猫狗队列的结构，要求如下：  
用户可以调用add方法将cat类或者dog类的实例放入队列中；  
用户可以调用poll方法，将队列中所有的实例按照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和cat的实例；

package CatDogPackage;
    
    import java.util.LinkedList;
    import java.util.Queue;
    
    //已经有的类:Pet,Dog,Cat
    class Pet {
        private String type;
    
        public Pet(String type) {
            this.type = type;
        }
    
        public String getPetType() {
            return this.type;
        }
    
    }
    
    class Dog extends Pet {
        public Dog() {
            super("Dog");
        }
    }
    
    class Cat extends Pet {
        public Cat() {
            super("Cat");
        }
    }
    
    //为解决猫狗队列问题新加的类:PetEnterQueue
    class PetEnterQueue {
        Pet pet;
        int count;
    
        public PetEnterQueue(Pet pet, int count) {
            this.pet = pet;
            this.count = count;
    
        }
    
        public Pet getPet() {
            return this.pet;
        }
    
        public int getCount() {
            return this.count;
        }
    
    }
    
    public class DogCatQueue {
    
        Queue<PetEnterQueue> DogQueue;
        Queue<PetEnterQueue> CatQueue;
        int count;
    
        public DogCatQueue() {
            DogQueue = new LinkedList<PetEnterQueue>();
            CatQueue = new LinkedList<PetEnterQueue>();
            count = 0;
        }
    
        public void add(Pet pet) {
            if (pet.getPetType().equals("Dog"))
                this.DogQueue.add(new PetEnterQueue(pet, count++));
            else if (pet.getPetType().equals("Cat"))
                this.CatQueue.add(new PetEnterQueue(pet, count++));
            else throw new RuntimeException("error:not Dog or Cat");
    
        }
    
        public boolean isEmpty() {
            return this.DogQueue.isEmpty() && this.CatQueue.isEmpty();
    
        }
    
        public boolean isDogQueueEmpty() {
            return this.DogQueue.isEmpty();
        }
    
        public boolean isCatQueueEmpty() {
            return this.DogQueue.isEmpty();
        }
    
        public Pet poll() {
            if (!this.DogQueue.isEmpty() && !this.CatQueue.isEmpty()) {
                if (this.DogQueue.peek().getCount() < this.CatQueue.peek().getCount())
                    return this.DogQueue.poll().getPet();
                else return this.CatQueue.poll().getPet();
    
            } else {
                if (!this.DogQueue.isEmpty())
                    return this.DogQueue.poll().getPet();
                else if (!this.CatQueue.isEmpty())
                    return this.CatQueue.poll().getPet();
                else throw new RuntimeException("error:DogCatQueue is empty");
            }
    
    
        }
    
        public Dog pollDog() {
            if (!this.DogQueue.isEmpty())
                return (Dog) this.DogQueue.poll().getPet();//强制转换
            else throw new RuntimeException("error:DogQueue is empty");
    
        }
    
        public Cat pollCat() {
            if (!this.CatQueue.isEmpty())
                return (Cat) this.CatQueue.poll().getPet();//强制转换
            else throw new RuntimeException("error:CatQueue is empty");
    
        }
    
    
    }

测试:

package CatDogPackage;
    
    import org.junit.Test;
    
    import static org.junit.Assert.*;
    
    public class DogCatQueueTest {
        @Test
        public static void main(String[] args) {
            DogCatQueue test = new DogCatQueue();
    
            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);
    
    //        while (!test.isDogQueueEmpty()) {
    //            System.out.println(test.pollDog().getPetType());
    //        }
            while (!test.isEmpty()) {
                System.out.println(test.poll().getPetType());
            }
        }
    
    }

[https_github.com_huijuanl_AlgorithmLearning.git]: https://github.com/huijuanl/AlgorithmLearning.git
[src]: https://github.com/huijuanl/AlgorithmLearning/tree/master/src
[main]: https://github.com/huijuanl/AlgorithmLearning/tree/master/src/main
[java]: https://github.com/huijuanl/AlgorithmLearning/tree/master/src/main/java