https://github.com/tmcgrath325/pairedlinkedlists.jl
An implementation of doubly-linked lists and skip lists in Julia
https://github.com/tmcgrath325/pairedlinkedlists.jl
data-structures julia
Last synced: 4 months ago
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An implementation of doubly-linked lists and skip lists in Julia
- Host: GitHub
- URL: https://github.com/tmcgrath325/pairedlinkedlists.jl
- Owner: tmcgrath325
- License: mit
- Created: 2022-08-02T14:53:00.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2025-03-04T19:00:00.000Z (7 months ago)
- Last Synced: 2025-06-09T21:08:32.373Z (4 months ago)
- Topics: data-structures, julia
- Language: Julia
- Homepage:
- Size: 156 KB
- Stars: 10
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# PairedLinkedLists
[](https://tmcgrath325.github.io/PairedLinkedLists.jl/stable/)
[](https://tmcgrath325.github.io/PairedLinkedLists.jl/dev/)
[](https://github.com/tmcgrath325/PairedLinkedLists.jl/actions/workflows/CI.yml?query=branch%3Amain)
[](https://codecov.io/gh/tmcgrath325/PairedLinkedLists.jl)
This package provides a few implementations of doubly-linked lists in Julia:
- `DoublyLinkedList`, a doubly-linked list with mutable nodes.
- `PairedLinkedList`, a doubly-linked list with mutable nodes which also contain a third link to a node in another `PairedLinkedList`.
- `TargetedLinkedList`, a doubly-linked list with mutable nodes which also contain a third link to a node in another list, which can be a `DoublyLinkedList`,`PairedLinkedList`, or a `TargetedLinkedList`.
The lists support many of the base methods for arrays:
```julia
julia> using PairedLinkedLists
julia> l = DoublyLinkedList{Int}();
julia> push!(l, 1:10...)
DoublyLinkedList{Int64}(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
julia> pushfirst!(l, 0)
DoublyLinkedList{Int64}(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
julia> pop!(l); l
DoublyLinkedList{Int64}(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
julia> popfirst!(l); l
DoublyLinkedList{Int64}(1, 2, 3, 4, 5, 6, 7, 8, 9)
julia> popat!(l, 5); l
DoublyLinkedList{Int64}(1, 2, 3, 4, 6, 7, 8, 9)
julia> insert!(l, 5, -1)
DoublyLinkedList{Int64}(1, 2, 3, 4, -1, 6, 7, 8, 9)
```
List nodes, rather than the data they contain, can be accessed via `getnode()`. Each node contains `data` as well as references to the previous and next nodes:
```julia
julia> using PairedLinkedLists;
julia> l = DoublyLinkedList{Int}(1:5...)
DoublyLinkedList{Int64}(1, 2, 3, 4, 5)
julia> node = getnode(l,3)
ListNode{Int64, DoublyLinkedList{Int64}}(3)
julia> node.next
ListNode{Int64, DoublyLinkedList{Int64}}(4)
julia> node.prev.data == 2
true
```
Iterating a list returns the data it contains, but nodes can be accessed during iteration by using `IteratingListNodes`:
```julia
julia> for data in l println(data) end
1
2
3
4
5
julia> for node in IteratingListNodes(l) println(node) end
ListNode{Int64, DoublyLinkedList{Int64}}(1)
ListNode{Int64, DoublyLinkedList{Int64}}(2)
ListNode{Int64, DoublyLinkedList{Int64}}(3)
ListNode{Int64, DoublyLinkedList{Int64}}(4)
ListNode{Int64, DoublyLinkedList{Int64}}(5)
```
[Skip lists](https://en.wikipedia.org/wiki/Skip_list) insert new data as appropriate to keep the list sorted, with O(log(n)) insertion and deletion times:
```julia
julia> using PairedLinkedLists
julia> sortedby = x -> (-x[2], x[1])
#5 (generic function with 1 method)
julia> data = [(x,y) for x in 1:2 for y in 1:2];
julia> sl = SkipList{eltype(data)}(data...) # using default sorting
SkipList{Tuple{Int64, Int64}, typeof(identity)}((1, 1), (1, 2), (2, 1), (2, 2))
julia> sl2 = SkipList{eltype(data)}(data...; sortedby=sortedby)
SkipList{Tuple{Int64, Int64}, var"#5#6"}((1, 2), (2, 2), (1, 1), (2, 1))
julia> push!(sl, (0,0))
SkipList{Tuple{Int64, Int64}, typeof(identity)}((0, 0), (1, 1), (1, 2), (2, 1), (2, 2))
julia> push!(sl2, (0,0))
SkipList{Tuple{Int64, Int64}, var"#5#6"}((1, 2), (2, 2), (1, 1), (2, 1), (0, 0))
```