# Summary 1: Pointer and update

1. LinkedList的结构 ![](https://1241747088-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Lpv9LvBSlFaukf_ALqh%2F-Lpv9NPw3Ji1X5Vk8CES%2F-Lpv9vpm-40QIQjMIv7i%2FLinkedList_01.jpg?generation=1569729532784777\&alt=media) ![](https://1241747088-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Lpv9LvBSlFaukf_ALqh%2F-Lpv9NPw3Ji1X5Vk8CES%2F-Lpv9vpoBm3ZcwUSXFlT%2FLinkedList_02.jpg?generation=1569729532782296\&alt=media)
2. insert a node ![](https://1241747088-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Lpv9LvBSlFaukf_ALqh%2F-Lpv9NPw3Ji1X5Vk8CES%2F-Lpv9vpqniVSWr69wne9%2FLinkedList_03.jpg?generation=1569729533124900\&alt=media) ![](https://1241747088-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Lpv9LvBSlFaukf_ALqh%2F-Lpv9NPw3Ji1X5Vk8CES%2F-Lpv9vpsdEFWq2bBcFpQ%2FLinkedList_04.jpg?generation=1569729533061318\&alt=media) **注意**：`head = newest`，这是为了把head指针重新更新，指向新的node
3. delete a node ![](https://1241747088-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Lpv9LvBSlFaukf_ALqh%2F-Lpv9NPw3Ji1X5Vk8CES%2F-Lpv9vpulq4nFfqNbUtq%2FLinkedList_05.jpg?generation=1569729532157981\&alt=media) ![](https://1241747088-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Lpv9LvBSlFaukf_ALqh%2F-Lpv9NPw3Ji1X5Vk8CES%2F-Lpv9vpweNgLixex3-tT%2FLinkedList_06.jpg?generation=1569729532682578\&alt=media)
4.  参考

    > [http://blog.csdn.net/feliciafay/article/details/6841115](http://blog.csdn.net/feliciafay/article/details/6841115)
5.  指针的含义

    ```java
    ListNode dummy = new ListNode(0); //建立一个dummynode
    dummy.next = head;                //把head连接在dummy后面
    head = dummy;                     //把head的指针移动到dummy处
    ```

    **注意**：`head = dummy`，**永远是左边的指针移动到右边去**。
