Golang中双向链表的InsertBefore()函数

package main

import "fmt"

type Node struct {
    Value int
    Prev  *Node
    Next  *Node
}

type DoublyLinkedList struct {
    Head *Node
    Tail *Node
}

func (dll *DoublyLinkedList) InsertBefore(refNode *Node, newNode *Node) {
    if refNode == nil || newNode == nil {
        return
    }

    newNode.Next = refNode
    newNode.Prev = refNode.Prev

    if refNode.Prev != nil {
        refNode.Prev.Next = newNode
    } else {
        dll.Head = newNode
    }

    refNode.Prev = newNode
}

func main() {
    dll := DoublyLinkedList{}

    node1 := &Node{Value: 1}
    node2 := &Node{Value: 2}
    node3 := &Node{Value: 3}

    dll.InsertBefore(nil, node1) // Insert at the beginning
    dll.InsertBefore(node1, node2)
    dll.InsertBefore(node2, node3)

    // Print the list
    curr := dll.Head
    for curr != nil {
        fmt.Println(curr.Value)
        curr = curr.Next
    }
}

func (dll *DoublyLinkedList) InsertBefore(refNode *Node, newNode *Node) {
    if refNode == nil || newNode == nil {
        return
    }
    // ... 插入逻辑
}

newNode.Next = refNode
newNode.Prev = refNode.Prev

if refNode.Prev != nil {
    refNode.Prev.Next = newNode
} else {
    dll.Head = newNode
}

refNode.Prev = newNode