Go Language implementation Jump Table (Skiplist)

Jump Table (skiplist) in the REDIS/LEVELDB is the core data structure, I simply rough with Golang implementation of the next.

As far as my simple understanding is concerned, on a regular list, when the insert, through the Random_level (), the layer becomes a lot of layers,

The more data is smaller, the greater the span. Look up from the top down, use space for time.

Write down the test code:

Package Mainimport ("FMT"//"Github.com/xclpkg/algorithm" "Math/rand") func main () {slt: = Newskiplist () for I: = n; i > 0; i--{slt. Insert (i)}slt. Printskiplist () slt. Search (SLT). Search (SLT). Search (SLT). Delete (SLT). Printskiplist ()}const skiplist_maxlevel = 8//32const skiplist_p = 4type skiplist struct {Header []listlevel int}func New Skiplist () *skiplist {return &skiplist{level:1, Header:make ([]list, Skiplist_maxlevel)}}func (SkipList *SkipList) Insert (key int) {update: = make (Map[int]*node) for I: = Len (Skiplist.header)-1; I >= 0; i--{if skiplist.header[i]. Len () > 0 {for E: = Skiplist.header[i]. Front (); E! = nil; E = E.next () {if e.value. int) >= Key {Update[i] = Ebreak}}//HEAER[LV]. List}//header Levellevel: = Skiplist.random_level () if level > skiplist.level {skiplist.level = level}for I: = 0; I < level; i++ {if V, OK: = Update[i]; OK {skiplist.header[i]. InsertBefore (Key, V)} else {Skiplist.header[i]. Pushback (key)}}}func (Skiplist *skiplist) Search (kEY int) *node {for I: = Len (Skiplist.header)-1; I >= 0; i--{if skiplist.header[i]. Len () > 0 {for E: = Skiplist.header[i]. Front (); E! = nil; E = E.next () {switch {case e.value. int) = = Key:fmt. Println ("Found level=", I, "key=", key) return Ecase E.value. (int) > Key:break}}//end for}//end if}//end forreturn Nil}func (skiplist *skiplist) Delete (key int) {for i: = Len (sk Iplist.header)-1; I >= 0; i--{if skiplist.header[i]. Len () > 0 {for E: = Skiplist.header[i]. Front (); E! = nil; E = E.next () {switch {case e.value. int) = = Key:fmt. Println ("Delete level=", I, "key=", Key) Skiplist.header[i].remove (e) Case E.value. (int) > Key:break}}//end for}//end if}//end for}func (skiplist *skiplist) printskiplist () {fmt. Println ("\nskiplist-------------------------------------------") for I: = SKIPLIST_MAXLEVEL-1; I >= 0; i--{fmt. Println ("Level:", I) if skiplist.header[i]. Len () > 0 {for E: = Skiplist.header[i]. Front (); E! = nil; E = E.next () {fmt. Printf ("%d", E.value)}//end for}//end iffmt. Println ("\ n--------------------------------------------------------")}//end For}func (skiplist *skiplist) random_ Level () int {level: = 1for (rand. Int31 () &0xffff)%skiplist_p = = 0 {level + = 1}if Level < Skiplist_maxlevel {return level} else {return skiplist_maxle Vel}}//////////////////////////////////////////////////////type Node struct {Next, prev *nodelist *listvalue Interfa Ce{}}type List struct {root Nodelen int}func (node *node) Next () *node {if p: = Node.next; Node.list! = Nil && P  ! = &node.list.root {return P}return nil}func (node *node) Prev () *node {if p: = Node.prev; Node.list! = Nil && P! = &node.list.root {return p}return nil}func (list *list) Init () *list {list.root.next = &AMP;LIST.ROOTLIST.ROOT.PR EV = &list.rootlist.len = 0return list}func new () *list {return new (list). Init ()}func (list *list) Lazyinit () {if List.root.next = = nil {list. Init ()}}func (list *list) Len () int {return List.len}func (list *list) RemoVE (e *node) *node {e.prev.next = E.nexte.next.prev = E.preve.next = Nile.prev = Nile.list = Nillist.len--return E}func (li St *list) Remove (e *node) interface{} {if e.list = = List {List.remove (e)}return e.value}func (List *list) Front () *node {i F List.len = = 0 {return nil}return list.root.next}func (list *list) back () *node {if List.len = = 0 {return Nil}return list . Root.prev}func (list *list) Insert (E, at *node) *node {n: = At.nextat.next = Ee.prev = Ate.next = Nn.prev = Ee.list = Lis  Tlist.len++return E}func (list *list) Insertvalue (v interface{}, at *node) *node {return List.insert (&node{value:v}, at)}func (list *list) insertbefore (v interface{}, Mark *node) *node {if mark.list! = List {return Nil}return LIST.INSERTV Alue (V, Mark.prev)}func (list *list) pushback (v interface{}) *node {list.lazyinit () return List.insertvalue (V, List.root.prev)}

Effect:  

Skiplist-------------------------------------------Level:7---------------------------------------------------- ----Level:6--------------------------------------------------------level:5------------------------------------ --------------------level:4--------------------------------------------------------level:393------------------ --------------------------------------level:236--------------------------------------------------------Level  : 2, the ten-in-a-si-si  3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45  46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 8384 85 86 All in all, 94, 98, Found level= 0 key= 20 Found level= 2 key= 36Found level= 3 key= 93Delete level= 1 key= 55Delete level= 0 key= 55SkipList-------------------------------------------level:7----------------------------- ---------------------------level:6--------------------------------------------------------Level:5------------- -------------------------------------------Level:4-------------------------------------------------------- level:393--------------------------------------------------------level:236---------------------------------- ----------------------Level:16-----------------------  -------------level:01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 7 9 8485 of the Bay of the Bay of Bayi, the 94 of the 98

Get.

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Go Language implementation Jump Table (Skiplist)