golang 鏈表

golang 鏈表

簡介

golang自身實現了一個雙向鏈表

匯入

import "container/list"

定義

// 鏈表元素type Element    func (e *Element) Next() *Element    func (e *Element) Prev() *Element//鏈表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 定義如下，value的類型為interface類型的，所以我們可以實現任意類型的鏈表type Element struct {    // The value stored with this element.    Value interface{}    // contains filtered or unexported fields}  

舉個例子

package mainimport (    "container/list"    "fmt")func main() {    //建立一個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)    }}

源碼實現

源碼目錄：/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)    }}