从链表中删除元素

    //删除链表中第index(o-based)个位置的元素，返回删除的全速
    //在链表中不是一个常用的操作，练习用:)
    public E remove(int index) {
        if (index < 0 || index > size)
            throw new IllegalArgumentException("Set failed.Illegal index.");
        Node prev = dummyHead;
        for(int i = 0; i < index ; i ++){
            prev = prev.next;
        }
        Node retNode = prev.next;
        prev.next = retNode.next;
        retNode.next = null;
        size --;
        return retNode.e;
    }

    //删除链表的第一个元素
    public E removeFirst(){
        return remove(0);
    }

    //删除元素的最后一个元素
    public E removeLast(){
        return remove(size - 1);
    }

public class Main {
    public static void main(String[] args) {
        LinkedList<Integer> linkedList = new LinkedList<>();
        for(int i = 0 ; i < 5; i ++){
            linkedList.addFirst(i);
            System.out.println(linkedList);
        }

        linkedList.add(2,666);
        System.out.println(linkedList);

        linkedList.remove(2);
        System.out.println(linkedList);

        linkedList.removeFirst();
        System.out.println(linkedList);

        linkedList.removeLast();
        System.out.println(linkedList);
    }
}

0->null
1->0->null
2->1->0->null
3->2->1->0->null
4->3->2->1->0->null
4->3->666->2->1->0->null
4->3->2->1->0->null
3->2->1->0->null
3->2->1->null