数据结构与算法【基础版】：2.9 队列

Myqueue.java

package com.kami.leetcode.queue;

import java.util.Arrays;

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(){
        //把数组的第0个元素取出来
        int element = elements[0];
        int[] newArr = new int[elements.length - 1];
        for(int i = 0; i < newArr.length; i++){
            newArr[i] = elements[i + 1];
        }
        elements = newArr;
        return element;
    }

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

}

测试类：MyqueueTest

public class MyqueueTest {
    public static void main(String[] args) {
        Myqueue myqueue = new Myqueue();
        myqueue.add(9);
        myqueue.add(8);
        myqueue.add(7);
        System.out.println(myqueue.poll());
        System.out.println(myqueue.isEmpty());
    }
}

结果：