一 双向链表简介

双向链表的定义是，一个节点有两个方向，分别储存当前节点的前驱节点，和后续节点；双向链表的删除只需要指定前驱节点，或者后续节点就可以进行删除操作；但是缺点也很明显每次添加节点时都需要2个指向，额外增加了内存空间消耗；

二 双向链表的实现

3.1 定义链表节点

1. 定义data存储数据，知识追寻者使用的时int类型，读者可以改为object类型；
2. 定义前驱节点previous
3. 定义后续节点next

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/**
 * @Author lsc
 * <p> 双向链表节点 </p>
 */
public class DoubleNode {

    //数据
    private Integer data;
    //后续节点节点
    private DoubleNode next;
    //前驱节点
    private DoubleNode previous;
    // 省略set get
}

最近更新： 2020-6-6 upds。

1. 两数之和

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

Example:

1. 两数之和

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

Example: