golang list implementation

Golang is an efficient and concise programming language that has great advantages in performance and concurrency. In Golang, there are many implementations of collection data structures, including lists. List is a very important data structure that can be used to store a set of data and supports inserting and deleting elements at any location. This article will introduce how to use Golang to implement a List.

1. Definition of List

List is a data structure, an ordered collection of elements. In a List, every element has a predecessor and a successor, except for the first and last elements. The first element has no predecessor elements, and the last element has no successor elements. List provides some basic operations, such as adding elements, deleting elements, accessing elements, etc.

2. Implementation of List

In Golang, to implement List, you can use a doubly linked list. A doubly linked list contains a pointer head pointing to the first node and a pointer tail pointing to the last node. Each node contains a pointer prev that points to the previous node and a pointer next that points to the next node, as well as a value val to store the value of the node. As shown below:

type ListNode struct {

prev *ListNode // 指向前一个节点
next *ListNode // 指向后一个节点
val  interface{// 当前节点的值
} 

}
type List struct {

head *ListNode // 指向第一个节点
tail *ListNode // 指向最后一个节点
len  int       // List的长度

}

When implementing List, we need Pay attention to the following points:

(1) Add elements

There are two main ways to add elements to the List, namely adding elements to the header and adding elements to the tail. We can implement them using AddFront and AddBack methods.

func (list *List) AddFront(val interface{}) {

node := &ListNode{
    prev: nil,
    next: list.head,
    val:  val,
}
if list.head == nil { // 如果链表为空
    list.head = node
    list.tail = node
} else {
    list.head.prev = node
    list.head = node
}
list.len++

}

func (list *List) AddBack(val interface{}) {

node := &ListNode{
    prev: list.tail,
    next: nil,
    val:  val,
}
if list.tail == nil { // 如果链表为空
    list.head = node
    list.tail = node
} else {
    list.tail.next = node
    list.tail = node
}
list.len++

}

(2) Deleting elements

Deleting elements is mainly divided into two situations, deleting header elements and deleting tail elements. We can also use the RemoveFront and RemoveBack methods to delete elements.

func (list *List) RemoveFront() {

if list.head == nil { // 如果链表为空
    return
}
if list.head == list.tail { // 如果链表只有一个元素
    list.head = nil
    list.tail = nil
    list.len = 0
    return
}
list.head = list.head.next
list.head.prev = nil
list.len--

}

func (list *List) RemoveBack() {

if list.tail == nil { // 如果链表为空
    return
}
if list.head == list.tail { // 如果链表只有一个元素
    list.head = nil
    list.tail = nil
    list.len = 0
    return
}
list.tail = list.tail.prev
list.tail.next = nil
list.len--

}

(3) Accessing elements

To access elements in List, you only need to traverse one by one starting from the head or tail of the table until you find the required element. We can use the Front and Back methods to access the first and last element in the List.

func (list *List) Front() interface{} {

if list.head == nil {
    return nil
}
return list.head.val

}

func (list *List) Back() interface{} {

if list.tail == nil {
    return nil
}
return list.tail.val

}

The above is the basic method of implementing List in Golang, which can be adjusted and optimized according to actual needs.

3. Summary

It is very simple to implement List in Golang, we only need to use a doubly linked list. List has been implemented in the standard library in Golang, so it is recommended to use the List in the standard library in actual use. If you need to customize the List, you can adjust and optimize the code given above according to actual needs.

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