数据结构-数据模拟队列

模拟单向队列

class ArrayQueue {
    private int maxSize;
    private int front;
    private int rear;
    private int[] arr;

    public ArrayQueue(int maxSize) {
        this.maxSize = maxSize;
        arr = new int[maxSize];
        front = -1;
        rear = -1;
    }

    //    判断是否为满
    public boolean isFull() {
        return rear == maxSize - 1;
    }

    //    判断是否为空
    public boolean isEmpty() {
        return rear == front;
    }

    //    添加数据
    public void add(int data) {
        if (isFull()) {
            System.out.println("队列已满");
            return;
        }
        rear++;
        arr[rear] = data;
    }

    //    获取队列数据
    public int get() {
        if (isEmpty()) {
            throw new RuntimeException("队列为空");

        }
        front++;
        return arr[front];
    }

    //    显示所有数据
    public void showQueue() {
        if (isEmpty()) {
            System.out.println("队列为空");
            return;
        }
        for (int i :
                arr) {
            System.out.println(i);

        }
    }

    //    获取头部数据
    public int getHead() {
        if (isEmpty()) {
            throw new RuntimeException("队列为空");

        }
        front++;
        return arr[front];
    }


}

模拟双向循环队列

class ArrayQueue2 {
    private int maxSize;//3
    private int front;//0
    private int rear;//0
    private int[] arr;

    public ArrayQueue2(int maxSize) {
        this.maxSize = maxSize;
        arr = new int[maxSize];
        front = 0;
        rear = 0;
    }

    //判断是为为满
    public boolean isFull() {
        return (rear+1)%maxSize == front;
    }

    //判断是否为空
    public boolean isEmpty() {
        return rear == front;
    }

    //添加数据
    public void add(int data) {
        if (isFull()) {
            System.out.println("队列已满");
            return;
        }

        arr[rear] = data;// 0 1 2
        rear = (rear+1) % maxSize;
    }

    //    获取队列数据
    public int get() {
        if (isEmpty()) {
            throw new RuntimeException("队列为空");

        }
        int value = arr[front];
        front = (front+1) %maxSize;
        return value;
    }

    //    显示所有数据
    public void showQueue() {
        if (isEmpty()) {
            System.out.println("队列为空");
            return;
        }
        for (int i = front; i < front + size(); i++) {
            System.out.println(i%maxSize +"  "+arr[i%maxSize]);
        }
    }

    //    获取头部数据
    public int getHead() {
        if (isEmpty()) {
            throw new RuntimeException("队列为空");

        }
        int v=arr[front];
        front++;
        return v;

    }
    //    获取有效数据个数
    public int size(){
        return (rear + maxSize - front)%maxSize;
    }




}