golang 链表
简介
golang自身实现了一个双向链表
导入
import "container/list"定义
// 链表元素
type Element
func (e *Element) Next() *Element
func (e *Element) Prev() *Element
//链表
type List
func New() *List
func (l *List) Back() *Element
func (l *List) Front() *Element
func (l *List) Init() *List
func (l *List) InsertAfter(v interface{}, mark *Element) *Element
func (l *List) InsertBefore(v interface{}, mark *Element) *Element
func (l *List) Len() int
func (l *List) MoveAfter(e, mark *Element)
func (l *List) MoveBefore(e, mark *Element)
func (l *List) MoveToBack(e *Element)
func (l *List) MoveToFront(e *Element)
func (l *List) PushBack(v interface{}) *Element
func (l *List) PushBackList(other *List)
func (l *List) PushFront(v interface{}) *Element
func (l *List) PushFrontList(other *List)
func (l *List) Remove(e *Element) interface{}
// Element 定义如下，value的类型为interface类型的，所以我们可以实现任意类型的链表
type Element struct {
// The value stored with this element.
Value interface{}
// contains filtered or unexported fields
} 举个例子
package main
import (
"container/list"
"fmt"
)
func main() {
//创建一个list
l := list.New()
e4 := l.PushBack(4)
e1 := l.PushFront(1)
l.InsertBefore(3, e4)
l.InsertAfter(2, e1)
for e := l.Front(); e != nil; e = e.Next() {
fmt.Println(e.Value)
}
}源码实现
源码目录：/usr/local/go/src/container/list（我的）
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package list implements a doubly linked list.
//
// To iterate over a list (where l is a *List):
// for e := l.Front(); e != nil; e = e.Next() {
// // do something with e.Value
// }
//
package list
// Element is an element of a linked list.
type Element struct {
// Next and previous pointers in the doubly-linked list of elements.
// To simplify the implementation, internally a list l is implemented
// as a ring, such that &l.root is both the next element of the last
// list element (l.Back()) and the previous element of the first list
// element (l.Front()).
next, prev *Element
// The list to which this element belongs.
list *List
// The value stored with this element.
Value interface{}
}
// Next returns the next list element or nil.
func (e *Element) Next() *Element {
if p := e.next; e.list != nil && p != &e.list.root {
return p
}
return nil
}
// Prev returns the previous list element or nil.
func (e *Element) Prev() *Element {
if p := e.prev; e.list != nil && p != &e.list.root {
return p
}
return nil
}
// List represents a doubly linked list.
// The zero value for List is an empty list ready to use.
type List struct {
root Element // sentinel list element, only &root, root.prev, and root.next are used
len int // current list length excluding (this) sentinel element
}
// Init initializes or clears list l.
func (l *List) Init() *List {
l.root.next = &l.root
l.root.prev = &l.root
l.len = 0
return l
}
// New returns an initialized list.
func New() *List { return new(List).Init() }
// Len returns the number of elements of list l.
// The complexity is O(1).
func (l *List) Len() int { return l.len }
// Front returns the first element of list l or nil.
func (l *List) Front() *Element {
if l.len == 0 {
return nil
}
return l.root.next
}
// Back returns the last element of list l or nil.
func (l *List) Back() *Element {
if l.len == 0 {
return nil
}
return l.root.prev
}
// lazyInit lazily initializes a zero List value.
func (l *List) lazyInit() {
if l.root.next == nil {
l.Init()
}
}
// insert inserts e after at, increments l.len, and returns e.
func (l *List) insert(e, at *Element) *Element {
n := at.next
at.next = e
e.prev = at
e.next = n
n.prev = e
e.list = l
l.len++
return e
}
// insertValue is a convenience wrapper for insert(&Element{Value: v}, at).
func (l *List) insertValue(v interface{}, at *Element) *Element {
return l.insert(&Element{Value: v}, at)
}
// remove removes e from its list, decrements l.len, and returns e.
func (l *List) remove(e *Element) *Element {
e.prev.next = e.next
e.next.prev = e.prev
e.next = nil // avoid memory leaks
e.prev = nil // avoid memory leaks
e.list = nil
l.len--
return e
}
// Remove removes e from l if e is an element of list l.
// It returns the element value e.Value.
func (l *List) Remove(e *Element) interface{} {
if e.list == l {
// if e.list == l, l must have been initialized when e was inserted
// in l or l == nil (e is a zero Element) and l.remove will crash
l.remove(e)
}
return e.Value
}
// PushFront inserts a new element e with value v at the front of list l and returns e.
func (l *List) PushFront(v interface{}) *Element {
l.lazyInit()
return l.insertValue(v, &l.root)
}
// PushBack inserts a new element e with value v at the back of list l and returns e.
func (l *List) PushBack(v interface{}) *Element {
l.lazyInit()
return l.insertValue(v, l.root.prev)
}
// InsertBefore inserts a new element e with value v immediately before mark and returns e.
// If mark is not an element of l, the list is not modified.
func (l *List) InsertBefore(v interface{}, mark *Element) *Element {
if mark.list != l {
return nil
}
// see comment in List.Remove about initialization of l
return l.insertValue(v, mark.prev)
}
// InsertAfter inserts a new element e with value v immediately after mark and returns e.
// If mark is not an element of l, the list is not modified.
func (l *List) InsertAfter(v interface{}, mark *Element) *Element {
if mark.list != l {
return nil
}
// see comment in List.Remove about initialization of l
return l.insertValue(v, mark)
}
// MoveToFront moves element e to the front of list l.
// If e is not an element of l, the list is not modified.
func (l *List) MoveToFront(e *Element) {
if e.list != l || l.root.next == e {
return
}
// see comment in List.Remove about initialization of l
l.insert(l.remove(e), &l.root)
}
// MoveToBack moves element e to the back of list l.
// If e is not an element of l, the list is not modified.
func (l *List) MoveToBack(e *Element) {
if e.list != l || l.root.prev == e {
return
}
// see comment in List.Remove about initialization of l
l.insert(l.remove(e), l.root.prev)
}
// MoveBefore moves element e to its new position before mark.
// If e or mark is not an element of l, or e == mark, the list is not modified.
func (l *List) MoveBefore(e, mark *Element) {
if e.list != l || e == mark || mark.list != l {
return
}
l.insert(l.remove(e), mark.prev)
}
// MoveAfter moves element e to its new position after mark.
// If e or mark is not an element of l, or e == mark, the list is not modified.
func (l *List) MoveAfter(e, mark *Element) {
if e.list != l || e == mark || mark.list != l {
return
}
l.insert(l.remove(e), mark)
}
// PushBackList inserts a copy of an other list at the back of list l.
// The lists l and other may be the same.
func (l *List) PushBackList(other *List) {
l.lazyInit()
for i, e := other.Len(), other.Front(); i > 0; i, e = i-1, e.Next() {
l.insertValue(e.Value, l.root.prev)
}
}
// PushFrontList inserts a copy of an other list at the front of list l.
// The lists l and other may be the same.
func (l *List) PushFrontList(other *List) {
l.lazyInit()
for i, e := other.Len(), other.Back(); i > 0; i, e = i-1, e.Prev() {
l.insertValue(e.Value, &l.root)
}
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