关于链表已在另一篇博客中有所描述：
https://blog.csdn.net/qq_33583322/article/details/79757044
首先队列的特性：先进先出，请自行脑补食物在身体内。。。。。呕~
class Queue{
Node first, last;
public void enqueue(Node n){
if(first == null){
first = n;
last = first;
}else{
last.next = n;
last = n;
}
}
public Node dequeue(){
if(first == null){
return null;
}else{
Node temp = new Node(first.val);
first = first.next;
return temp;
}
}
}效果图：
