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https://github.com/huandu/skiplist
Fast and easy-to-use skip list for Go.
https://github.com/huandu/skiplist
algortihm database go hashmap skiplist
Last synced: about 18 hours ago
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Fast and easy-to-use skip list for Go.
- Host: GitHub
- URL: https://github.com/huandu/skiplist
- Owner: huandu
- License: mit
- Created: 2012-04-23T10:02:47.000Z (over 12 years ago)
- Default Branch: master
- Last Pushed: 2024-09-23T05:02:10.000Z (3 months ago)
- Last Synced: 2024-11-17T12:51:04.097Z (26 days ago)
- Topics: algortihm, database, go, hashmap, skiplist
- Language: Go
- Homepage: https://pkg.go.dev/github.com/huandu/skiplist
- Size: 50.8 KB
- Stars: 381
- Watchers: 11
- Forks: 67
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-distributed-system-projects - skiplist - a Golang implementation of the skiplist data structure
- awesome-algorithms - skiplist - Skip list implemented in Go (Awesome Algorithms / SL - Skip List (跳跃列表))
README
# Skip List in Golang
[](https://github.com/huandu/skiplist/actions)
[](https://pkg.go.dev/github.com/huandu/skiplist)
[](https://goreportcard.com/report/github.com/huandu/skiplist)
[](https://coveralls.io/github/huandu/skiplist?branch=master)
Skip list is an ordered map. See wikipedia page [skip list](http://en.wikipedia.org/wiki/Skip_list) to learn algorithm details about this data structure.
Highlights in this implementation:
- Built-in types can be used as key with predefined key types. See [Int](https://pkg.go.dev/github.com/huandu/skiplist#Int) and related constants as a sample.
- Support custom comparable function so that any type can be used as key.
- Key sort order can be changed quite easily. See [Reverse](https://pkg.go.dev/github.com/huandu/skiplist#Reverse) and [LessThanFunc](https://pkg.go.dev/github.com/huandu/skiplist#LessThanFunc).
- Rand source and max level can be changed per list. It can be useful in performance critical scenarios.
## Install
Install this package through `go get`.
```bash
go get github.com/huandu/skiplist
```
## Basic Usage
Here is a quick sample.
```go
package main
import (
"fmt"
"github.com/huandu/skiplist"
)
func main() {
// Create a skip list with int key.
list := skiplist.New(skiplist.Int)
// Add some values. Value can be anything.
list.Set(12, "hello world")
list.Set(34, 56)
list.Set(78, 90.12)
// Get element by index.
elem := list.Get(34) // Value is stored in elem.Value.
fmt.Println(elem.Value) // Output: 56
next := elem.Next() // Get next element.
prev := next.Prev() // Get previous element.
fmt.Println(next.Value, prev.Value) // Output: 90.12 56
// Or, directly get value just like a map
val, ok := list.GetValue(34)
fmt.Println(val, ok) // Output: 56 true
// Find first elements with score greater or equal to key
foundElem := list.Find(30)
fmt.Println(foundElem.Key(), foundElem.Value) // Output: 34 56
// Remove an element for key.
list.Remove(34)
}
```
## Using `GreaterThanFunc` and `LessThanFunc`
Define your own `GreaterThanFunc` or `LessThanFunc` to use any custom type as the key in a skip list.
The signature of `GreaterThanFunc` are `LessThanFunc` are the same.
The only difference between them is that `LessThanFunc` reverses result returned by custom func
to make the list ordered by key in a reversed order.
```go
type T struct {
Rad float64
}
list := New(GreaterThanFunc(func(k1, k2 interface{}) int {
s1 := math.Sin(k1.(T).Rad)
s2 := math.Sin(k2.(T).Rad)
if s1 > s2 {
return 1
} else if s1 < s2 {
return -1
}
return 0
}))
list.Set(T{math.Pi / 8}, "sin(π/8)")
list.Set(T{math.Pi / 2}, "sin(π/2)")
list.Set(T{math.Pi}, "sin(π)")
fmt.Println(list.Front().Value) // Output: sin(π)
fmt.Println(list.Back().Value) // Output: sin(π/2)
```
## License
This library is licensed under MIT license. See LICENSE for details.