Golang标准库container/list的用法图文详解

import (
	"container/list"
	"fmt"
)

func Example() {
	// Create a new list and put some numbers in it.
	l := list.New()
	e4 := l.PushBack(4)
	e1 := l.PushFront(1)
	l.InsertBefore(3, e4)
	l.InsertAfter(2, e1)

	// Iterate through list and print its contents.
	for e := l.Front(); e != nil; e = e.Next() {
		fmt.Println(e.Value)
	}

	// Output:
	// 1
	// 2
	// 3
	// 4
}

// 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 any
}

// 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 if the list is empty.
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 if the list is empty.
func (l *List) Back() *Element {
	if l.len == 0 {
		return nil
	}
	return l.root.prev
}

// insert inserts e after at, increments l.len, and returns e.
func (l *List) insert(e, at *Element) *Element {
	e.prev = at
	e.next = at.next
    
    // 此时的 e.prev 已经是 at 节点
	e.prev.next = e
	e.next.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 any, at *Element) *Element {
	return l.insert(&Element{Value: v}, at)
}

// remove removes e from its list, decrements l.len
func (l *List) remove(e *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--
}

// move moves e to next to at.
func (l *List) move(e, at *Element) {
	if e == at {
		return
	}
	// 移除到 e 在原来链表中的关系
	e.prev.next = e.next
	e.next.prev = e.prev
	
	// 这里和 insert 操作是一样的
	e.prev = at
	e.next = at.next
	e.prev.next = e
	e.next.prev = e
}

// Remove removes e from l if e is an element of list l.
// It returns the element value e.Value.
// The element must not be nil.
func (l *List) Remove(e *Element) any {
	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 any) *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 any) *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.
// The mark must not be nil.
func (l *List) InsertBefore(v any, 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.
// The mark must not be nil.
func (l *List) InsertAfter(v any, 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.
// The element must not be nil.
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.move(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.
// The element must not be nil.
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.move(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.
// The element and mark must not be nil.
func (l *List) MoveBefore(e, mark *Element) {
	if e.list != l || e == mark || mark.list != l {
		return
	}
	l.move(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.
// The element and mark must not be nil.
func (l *List) MoveAfter(e, mark *Element) {
	if e.list != l || e == mark || mark.list != l {
		return
	}
	l.move(e, mark)
}

// PushBackList inserts a copy of another list at the back of list l.
// The lists l and other may be the same. They must not be nil.
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 another list at the front of list l.
// The lists l and other may be the same. They must not be nil.
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)
	}
}

package main

import (
	"container/list"
	"fmt"
	"sort"
	"strings"
	"time"
)


type Order struct {
	Price       float64
	CreatedTime time.Time
}

// TwoDList 二维链表，要求第一维以价格从低到高排序，第二维以时间从小到大排序。
type TwoDList struct {
	// 索引相同,即表示价格相同,同一索引的链表节点,越靠后时间越大
	// 索引越大,价格越高
	Rows []*list.List
}

func NewTwoDList() *TwoDList {
	return &TwoDList{
		Rows: make([]*list.List, 0),
	}
}

func (tdl *TwoDList) AddNode(price float64, createdTime time.Time) {

	order := &Order{Price: price, CreatedTime: createdTime}
	// 1、
	index := sort.Search(len(tdl.Rows), func(i int) bool {
		return tdl.Rows[i].Front().Value.(*Order).Price >= order.Price
	})
	if index == len(tdl.Rows) {
		// 此价格不存在 tdl 中, 新增
		newList := list.New()
		newList.PushFront(order)

		tdl.Rows = append(tdl.Rows, newList)
		return
	}

	// 判断 index 处的价格是否和 order.Price 相等,
	// 相等, 则往链表添加
	// 不相等, 则需要先将 index 之后的往后移一位
	if order.Price != tdl.Rows[index].Front().Value.(*Order).Price {
		newList := list.New()
		newList.PushFront(order)

		// 插入元素 newList
		tdl.Rows = append(tdl.Rows[:index], append([]*list.List{newList}, tdl.Rows[index:]...)...)
		return
	}

	// 时间从小到大排
	curRow := tdl.Rows[index]
	insertPosition := curRow.Front()

	for insertPosition != nil && order.CreatedTime.After(insertPosition.Value.(*Order).CreatedTime) {
		insertPosition = insertPosition.Next()
	}

	if insertPosition == nil {
		curRow.PushBack(order)
	} else {
		curRow.InsertBefore(order, insertPosition)
	}
}

func (tdl *TwoDList) Print() {
	for i, row := range tdl.Rows {
		fmt.Printf("index: %d\n", i)
		for node := row.Front(); node != nil; node = node.Next() {
			order := node.Value.(*Order)
			fmt.Printf("order price: %f, time: %v \n", order.Price, order.CreatedTime)
		}
		fmt.Println(strings.Repeat("-", 20))
	}
}

func main() {
	// 创建一个新的二维链表
	myTwoDList := NewTwoDList()

	// 向二维链表添加节点
	myTwoDList.AddNode(100, time.Now())
	myTwoDList.AddNode(75, time.Now().Add(time.Hour))
	myTwoDList.AddNode(75, time.Now().Add(time.Hour))
	myTwoDList.AddNode(150, time.Now().Add(2*time.Hour))
	myTwoDList.AddNode(75, time.Now().Add(3*time.Hour))
	myTwoDList.AddNode(200, time.Now().Add(4*time.Hour))

	// 打印二维链表
	myTwoDList.Print()
}