MyQueue.java

public class  MyQueue {
    int[] elements;
    public MyQueue(){
        elements = new int[0];
    }
    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(isEmpty()){
            throw  new RuntimeException("Queue is empty");
        }
        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;
    }
    public boolean isEmpty(){
        return elements.length==0;
    }
}