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deque.go
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deque.go
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package internal
const Nil = 0
type (
Pointer uint32
Element[T any] struct {
prev, addr, next Pointer
value T
}
// Deque 可以不使用New函数, 声明为值类型自动初始化
Deque[T any] struct {
head, tail Pointer // 头尾指针
length int // 长度
stack Stack[Pointer] // 回收站
elements []Element[T] // 元素列表
template Element[T] // 空值模板
}
)
func (c Pointer) IsNil() bool {
return c == Nil
}
func (c *Element[T]) Addr() Pointer {
return c.addr
}
func (c *Element[T]) Next() Pointer {
return c.next
}
func (c *Element[T]) Prev() Pointer {
return c.prev
}
func (c *Element[T]) Value() T {
return c.value
}
// New 创建双端队列
func New[T any](capacity int) *Deque[T] {
return &Deque[T]{elements: make([]Element[T], 1, 1+capacity)}
}
func (c *Deque[T]) Get(addr Pointer) *Element[T] {
if addr > 0 {
return &(c.elements[addr])
}
return nil
}
// getElement 追加元素一定要先调用此方法, 因为追加可能会造成扩容, 地址发生变化!!!
func (c *Deque[T]) getElement() *Element[T] {
if len(c.elements) == 0 {
c.elements = append(c.elements, c.template)
}
if c.stack.Len() > 0 {
addr := c.stack.Pop()
v := c.Get(addr)
v.addr = addr
return v
}
addr := Pointer(len(c.elements))
c.elements = append(c.elements, c.template)
v := c.Get(addr)
v.addr = addr
return v
}
func (c *Deque[T]) putElement(ele *Element[T]) {
c.stack.Push(ele.addr)
*ele = c.template
}
// Reset 重置
func (c *Deque[T]) Reset() {
c.autoReset()
}
func (c *Deque[T]) autoReset() {
c.head, c.tail, c.length = Nil, Nil, 0
c.stack = c.stack[:0]
c.elements = c.elements[:1]
}
func (c *Deque[T]) Len() int {
return c.length
}
func (c *Deque[T]) Front() *Element[T] {
return c.Get(c.head)
}
func (c *Deque[T]) Back() *Element[T] {
return c.Get(c.tail)
}
func (c *Deque[T]) PushFront(value T) *Element[T] {
ele := c.getElement()
ele.value = value
c.doPushFront(ele)
return ele
}
func (c *Deque[T]) doPushFront(ele *Element[T]) {
c.length++
if c.head.IsNil() {
c.head, c.tail = ele.addr, ele.addr
return
}
head := c.Get(c.head)
head.prev = ele.addr
ele.next = head.addr
c.head = ele.addr
}
func (c *Deque[T]) PushBack(value T) *Element[T] {
ele := c.getElement()
ele.value = value
c.doPushBack(ele)
return ele
}
func (c *Deque[T]) doPushBack(ele *Element[T]) {
c.length++
if c.tail.IsNil() {
c.head, c.tail = ele.addr, ele.addr
return
}
tail := c.Get(c.tail)
tail.next = ele.addr
ele.prev = tail.addr
c.tail = ele.addr
}
func (c *Deque[T]) PopFront() (value T) {
if ele := c.Front(); ele != nil {
value = ele.value
c.doRemove(ele)
c.putElement(ele)
if c.length == 0 {
c.autoReset()
}
}
return value
}
func (c *Deque[T]) PopBack() (value T) {
if ele := c.Back(); ele != nil {
value = ele.value
c.doRemove(ele)
c.putElement(ele)
if c.length == 0 {
c.autoReset()
}
}
return value
}
func (c *Deque[T]) InsertAfter(value T, mark Pointer) *Element[T] {
if mark.IsNil() {
return nil
}
c.length++
e1 := c.getElement()
e0 := c.Get(mark)
e2 := c.Get(e0.next)
e1.prev, e1.next, e1.value = e0.addr, e0.next, value
if e2 != nil {
e2.prev = e1.addr
}
e0.next = e1.addr
if e1.next.IsNil() {
c.tail = e1.addr
}
return e1
}
func (c *Deque[T]) InsertBefore(value T, mark Pointer) *Element[T] {
if mark.IsNil() {
return nil
}
c.length++
e1 := c.getElement()
e2 := c.Get(mark)
e0 := c.Get(e2.prev)
e1.prev, e1.next, e1.value = e2.prev, e2.addr, value
if e0 != nil {
e0.next = e1.addr
}
e2.prev = e1.addr
if e1.prev.IsNil() {
c.head = e1.addr
}
return e1
}
func (c *Deque[T]) MoveToBack(addr Pointer) {
if ele := c.Get(addr); ele != nil {
c.doRemove(ele)
ele.prev, ele.next = Nil, Nil
c.doPushBack(ele)
}
}
func (c *Deque[T]) MoveToFront(addr Pointer) {
if ele := c.Get(addr); ele != nil {
c.doRemove(ele)
ele.prev, ele.next = Nil, Nil
c.doPushFront(ele)
}
}
func (c *Deque[T]) Update(addr Pointer, value T) {
if ele := c.Get(addr); ele != nil {
ele.value = value
}
}
func (c *Deque[T]) Remove(addr Pointer) {
if ele := c.Get(addr); ele != nil {
c.doRemove(ele)
c.putElement(ele)
if c.length == 0 {
c.autoReset()
}
}
}
func (c *Deque[T]) doRemove(ele *Element[T]) {
var prev, next *Element[T] = nil, nil
var state = 0
if !ele.prev.IsNil() {
prev = c.Get(ele.prev)
state += 1
}
if !ele.next.IsNil() {
next = c.Get(ele.next)
state += 2
}
c.length--
switch state {
case 3:
prev.next = next.addr
next.prev = prev.addr
case 2:
next.prev = Nil
c.head = next.addr
case 1:
prev.next = Nil
c.tail = prev.addr
default:
c.head = Nil
c.tail = Nil
}
}
func (c *Deque[T]) Range(f func(ele *Element[T]) bool) {
for i := c.Get(c.head); i != nil; i = c.Get(i.next) {
if !f(i) {
break
}
}
}
func (c *Deque[T]) Clone() *Deque[T] {
var v = *c
v.elements = make([]Element[T], len(c.elements))
v.stack = make([]Pointer, len(c.stack))
copy(v.elements, c.elements)
copy(v.stack, c.stack)
return &v
}
type Stack[T any] []T
// Len 获取元素数量
func (c *Stack[T]) Len() int {
return len(*c)
}
// Push 追加元素
func (c *Stack[T]) Push(v T) {
*c = append(*c, v)
}
// Pop 弹出元素
func (c *Stack[T]) Pop() T {
n := c.Len()
value := (*c)[n-1]
*c = (*c)[:n-1]
return value
}