go 双向链表 DoublyLinkedList

package main


/*
双向链表也叫双链表，是链表的一种，它的每个数据结点中都有两个指针，分别指向直接后继和直接前驱。所以，从双向链表中的任意一个结点开始，都可以很方便地访问它的前驱结点和后继结点。一般我们都构造双向循环链表。

*/
func main() {

}

type Node struct {
data int
next *Node
prev *Node
}

type LinkedList struct {
head *Node
tail *Node
}

func (list *LinkedList) InsertList(i int){
data := &Node{data:i}
if list.head != nil {
list.head.prev = data
data.next = list.head
}
list.head = data
}

func (list *LinkedList)InsertLast(i int){
data := &Node{data:i}
if list.head == nil {
list.head = data
list.tail = data
return
}
if list.tail != nil{
list.tail.next = data
data.prev = list.tail
}
list.tail = data
}

func (list *LinkedList) RemoveByValue(i int) bool{
if list.head == nil {
return false
}
if list.head.data == i {
list.head = list.head.next
list.head.prev = nil
return true
}
if list.tail.data == i {
list.tail = list.tail.prev
list.tail.next = nil
return true
}

current := list.head
for current.next != nil {
if current.next.data == i {
if current.next.next != nil {
current.next.next.prev = current
}
current.next = current.next.next
return true
}
current = current.next
}
return false

}

func (list *LinkedList)RemovedByIndex(i int) bool {
if list.head == nil {
return false
}
if i < 0 {
return false
}

if i == 0 {
list.head.prev = nil
list.head = list.head.next
return true
}
current := list.head
for u := 1; u < i;u ++ {
if current.next.next ==  nil {
return false
}
current = current.next
}

if current.next.next != nil {
current.next.next.prev = current
}
current.next = current.next.next
return true


}


func (list *LinkedList) SearchValue (i int) bool {
if list.head == nil {
return false
}

current := list.head
for current != nil {
if current.data == i {
return true
}
current = current.next
}
return false
}


func (list *LinkedList) GetFirst() (int,bool){
if list.head == nil {
return 0,false
}
return list.head.data,true
}

func (list *LinkedList)Getlast() (int,bool){
if list.head == nil {
return 0,false
}
current := list.head
for current.next != nil {
current = current.next
}
return current.data,true
}

func (list *LinkedList)GetSize() int {
count := 0
current := list.head
for current != nil {
count += 1
current = current.next
}
return count
}


func (list *LinkedList)GetItemsFromStart() []int {
var items []int
current := list.head
for current != nil{
items = append(items,current.data)
current = current.next
}
return items
}

func (list *LinkedList)GetItemsFromEnd() []int {
var items []int
current := list.tail
for current != nil{
items = append(items,current.data)
current = current.prev
}
return items
}