Write before:

We talked about the stack in the last article—— What is stack?
I believe that many little friends understand the stack;
So this time, we also use the form of comics to talk about what is the queue;

Mind mapping:

What is a queue?

Characteristics of the queue?

Storage structure of the queue:

Code implementation:

Sequential storage of queues:

Method class:

//Join the team
    public void Push_SeqQueue(SeqQueue queue, Object data){
        if(queue==null){
            return;
        }
        if(data==null){
            return;
        }
        //If the queue capacity is less than or equal to the array capacity
        if(queue.size==Max_Size){
            return;
        }
        //Element entry
        queue.data[queue.size]=data;
        queue.size++;
    }

 //Return to team leader element
    public Object Front_SeqQueue(SeqQueue queue){
        if(queue==null){
            return null;
        }
        if(queue.size==0){
            return null;
        }
        //Team head element subscript is 0
        return queue.data[0];
    }

//Team out
    public void Pop_SeqQueue(SeqQueue queue){
        if(queue==null){
            return;
        }
        if(queue.size==0){
            return;
        }
        //All elements need to be moved for outbound operation
        for (int i = 0; i < queue.size-1; i++) {
            queue.data[i]=queue.data[i+1];
        }
        queue.size--;
    }

Main function:

public static void main(String[] args) {
        SeqQueueDao seqQueueDao=new SeqQueueDao();
        //Initialize queue
        SeqQueue queue=seqQueueDao.Init_SeqQueue();

        //Join the team
        seqQueueDao.Push_SeqQueue(queue,"A");
        seqQueueDao.Push_SeqQueue(queue,"B");
        seqQueueDao.Push_SeqQueue(queue,"C");
        seqQueueDao.Push_SeqQueue(queue,"D");
        seqQueueDao.Push_SeqQueue(queue,"E");

        //Team out
        while (queue.size>0){
            //Find team leader element
            Object o=seqQueueDao.Front_SeqQueue(queue);
            System.out.println(o);
            //Team out
            seqQueueDao.Pop_SeqQueue(queue);
        }
    }

Operation result:

Chained storage of queues:

Method class:

//Queue entry
    public void Push_LinkQueue(LinkQueue queue,Object data){
        if (queue == null){
            return;
        }
        if (data == null){
            return;
        }
        //Create the newly inserted node, the first element after the queue top pointer, because element insertion or deletion can only be performed at the top of the queue
        LinkQueueNode newNode=new LinkQueueNode(data,null);
        //Enter insert operation
        newNode.next=queue.head.next;
        //next of the queue top pointer is equal to the new insertion node
        queue.head.next=newNode;
        //Queue capacity plus 1
        queue.size++;
    }

 //Outgoing queue
    public void Pop_LinkQueue(LinkQueue queue){
        if (queue == null){
            return;
        }
        if (queue.size == 0){
            return;
        }
        //pPrev refers to the head node, and pCurrent refers to the first element after the head node until pCurrent is empty
        LinkQueueNode pPrev=queue.head;
        LinkQueueNode pCurrent=pPrev.next;
        while (pCurrent.next!=null){
            pPrev=pCurrent;
            pCurrent=pPrev.next;
        }
        pPrev.next=null;
        //Queue capacity minus 1
        queue.size--;
    }

//Return to team leader element
    public Object Front_LinkQueue(LinkQueue queue){
        if (queue == null){
            return null;
        }
        if (queue.size == 0){
            return null;
        }
        //The team head element is the element inserted in front of you. Use the loop to find the team head element all the time
        LinkQueueNode pCurrent=queue.head;
        while (pCurrent.next!=null){
            pCurrent=pCurrent.next;
        }
        return pCurrent.data;
    }

Main function:

public static void main(String[] args) {
        LinkQueueDao linkQueueDao=new LinkQueueDao();
        //Initialize queue
        LinkQueue queue=linkQueueDao.Init_LinkQueue();

        //Queue entry
        linkQueueDao.Push_LinkQueue(queue,"A");
        linkQueueDao.Push_LinkQueue(queue,"B");
        linkQueueDao.Push_LinkQueue(queue,"C");
        linkQueueDao.Push_LinkQueue(queue,"D");
        linkQueueDao.Push_LinkQueue(queue,"E");

        //Output queue element
        while(!linkQueueDao.IsEmpty_LinkQueue(queue)){
            //Find team leader element
            Object o=linkQueueDao.Front_LinkQueue(queue);
            System.out.println(o);
            //Outgoing queue
            linkQueueDao.Pop_LinkQueue(queue);
        }
    }

Operation result:

Well, I'll share it with you today. Next time I'll give you an introduction to the tree!

                        **It's not easy to be original. Please pay attention~**