LinkedList源码分析-蒲公英云

LinkedList源码分析

向右看齐 2022-03-10 03:58 570阅读 0赞

1.有双链表组成，哪两个？first，last。

添加last链表

void linkLast(E e) {
        final Node<E> l = last;
        final Node<E> newNode = new Node<>(l, e, null);
        last = newNode;
        if (l == null)
            first = newNode;
        else
            l.next = newNode;
        size++;
        modCount++;
    }

new Node<>(l, e, null);这个是重点

Node(Node<E> prev, E element, Node<E> next) {
            this.item = element;
            this.next = next;
            this.prev = prev;
        }

在这里看来链表中存储着这个数的前一个数，和后一个数

add(E e)

public boolean add(E e) {
        linkLast(e);
        return true;
    }
void linkLast(E e) {
        final Node<E> l = last;
        final Node<E> newNode = new Node<>(l, e, null);
        last = newNode;
        if (l == null)
            first = newNode;
        else
            l.next = newNode;
        size++;
        modCount++;
    }

在last链表添加

push(E e)

public void push(E e) {
        addFirst(e);
    }

表头添加

输出

Iterator iterator=linkedList.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }

!!!尽量不要在foreach方法中使用remove,add方法

remove()

public E remove() {
        return removeFirst();
    }

删除头链表

demo

LinkedList linkedList=new LinkedList();
        linkedList.add("1");
        linkedList.add("2");
        linkedList.add(3);
//先进先出 
        System.out.println(linkedList.getFirst()+" "+linkedList.getLast());
        Iterator iterator=linkedList.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }
        linkedList=new LinkedList();
        linkedList.push("1");
        linkedList.push(2);
        linkedList.push(3);
//先进后出，像栈
        Iterator iterator1=linkedList.iterator();
        while (iterator1.hasNext()){
            System.out.println(iterator1.next());
        }