Java数据结构之队列

Posted 2020-11-30 包莹莹

public class MyQueue {
    int[] elements;
    public MyQueue()
    {
        elements = new int[0];
    }

    //入队
    public void add(int element)
    {
        int[] newArr = new int[elements.length+1];

        for(int i = 0;i < elements.length;i++)
        {
            newArr[i] = elements[i];
        }

        newArr[elements.length] = element;

        elements = newArr;
    }

    //出队
    public int poll()
    {
        if(elements.length == 0)
        {
            throw new RuntimeException("Queue is empty");
        }

        int[] newArr = new int[elements.length-1];
        int elemment = elements[0];
        for(int i = 1;i < elements.length;i++)
        {
            newArr[i-1] = elements[i];
        }
        elements = newArr;
        return elemment;
    }

    //判断队列是否为空
    public boolean isEmpty()
    {
        return elements.length == 0;
    }
}