如何将一个队列拆分成两个队列？

Question

Problem

Given a queue, split the queue into two queues:

• one containing odd numbers and the other even numbers.
• The relative order of elements must be maintained in both the queues.
• Return an array containing the two queues, the 0th index should contain the queue of odd numbers and the 1st index should contain the queue of even numbers.

Code

Here is what I've tried so far. I am currently getting empty queue.

class Queue {

private int front;
private int rear;
private int maxSize;
private int arr[];
  
Queue(int maxSize) {
    this.front = 0;
    this.rear = -1;
    this.maxSize = maxSize;
    this.arr = new int[this.maxSize];
}
  
public boolean isFull() {
    if (rear == maxSize - 1) {
        return true;
    }
    return false;
}
        
public boolean enqueue(int data) {
    if (isFull()) {
        return false;
    } else {
        arr[++rear] = data;
        return true;
    }
}

public void display() {
    if(isEmpty())
        System.out.println("Queue is empty!");
    else {
        for (int index = front; index <= rear; index++) {
            System.out.println(arr[index]);
        }
    }
}
        
public boolean isEmpty() {
    if (front > rear)
        return true;
    return false;
}
        
public int dequeue() {
    if (isEmpty()) {
        return Integer.MIN_VALUE;
    } else {
        int data = arr[this.front];
        arr[front++] = Integer.MIN_VALUE;
        return data;
    }
}

public int getMaxSize() {
    return maxSize;
}
}

class Main {

public static void main(String[] args) {
        
    Queue queue = new Queue(7);
    queue.enqueue(2);
    queue.enqueue(7);
    queue.enqueue(9);
    queue.enqueue(4);
    queue.enqueue(6);
    queue.enqueue(5);
    queue.enqueue(10);
    
    Queue[] queueArray = splitQueue(queue);
        
    System.out.println("Elements in the queue of odd numbers");
    queueArray[0].display();
        
    System.out.println("\nElements in the queue of even numbers");
    queueArray[1].display();

}

// function to split the queue into two queues; 
    // 1. one even. one odd.
    // 2. relative elements must be maintained in both queues.
    // 3. 0th index returns queue of odd numbers
    // 4. 1st index returns queue of even numbers
public static Queue[] splitQueue(Queue queue) {
    
    // create queue array for 0th index for odd and 1st index for even
    Queue[] numberArr = new Queue[2];
    
    // create two queues - odd and even queue
    Queue oddQueue = queue;
    Queue evenQueue = queue;
    
    // seperate odd and even
    while (!oddQueue.isEmpty()) {
        // start dequeue
        int val = queue.dequeue();
        
        // check even odd
        if (val % 2 == 0) {
            System.out.println(val + " - Even");
            evenQueue.enqueue(val);
        }
        else {
            System.out.println(val + " - Odd");
            oddQueue.enqueue(val);
        }
    }
    evenQueue.display();
    oddQueue.display();
    
    // assign odd numbers queue to 0th index of array
    numberArr[0] = oddQueue;
    // assign even numbers queue to 1th index of array
    numberArr[1] = evenQueue;
    
    if ((!oddQueue.isEmpty() && !evenQueue.isEmpty())) {
        return numberArr;
    }
    return null;
}
}

I am currently doing a queue exercise and am currently stuck on this implementation. I would appreciate any help for this.

Edit: I've provided my solution on what I've tried so far.

Answer 1

在while循环中检查形参“queue”是否为空=> while(!queue.isEmpty())

Answer 2

public static Queue[] splitQueue(Queue queue) {
       //Implement your code here and change the return value accordingly
    Queue[] numberArr = new Queue[2];
      //create two queues - odd and even queue
    Queue oddQueue=new Queue(queue.getMaxSize() );
    Queue evenQueue=new Queue(queue.getMaxSize());
    // seperate odd and even
   while(!(queue.isEmpty()))
   {
       int val=queue.dequeue();
       //System.out.println(val);
       if(val%2==0)
       {
           evenQueue.enqueue(val);
       }else
       {
           oddQueue.enqueue(val);
       }
   }
    // assign odd numbers queue to 0th index of array
    numberArr[0] = oddQueue;
    // assign even numbers queue to 1th index of array
    numberArr[1] = evenQueue;
    return numberArr;

    }

I worked on your code and I got your errors 1] in while condition use the condition like (!queue.isEmpty()) 2] you are not creating the new queues .it will be created by new keyword only like, Queue oddQueue=new Queue(queue.getMaxSize() );