https://github.com/discord/deque

Fast bounded deque using two rotating lists.
https://github.com/discord/deque

datastructures elixir

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Fast bounded deque using two rotating lists.

• Host: GitHub
• URL: https://github.com/discord/deque
• Owner: discord
• License: mit
• Created: 2017-02-15T21:00:12.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2023-05-31T02:35:12.000Z (over 2 years ago)
• Last Synced: 2025-01-28T12:56:19.289Z (12 months ago)
• Topics: datastructures, elixir
• Language: Elixir
• Homepage:
• Size: 11.7 KB
• Stars: 153
• Watchers: 176
• Forks: 18
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Deque

[![Master](https://travis-ci.org/discordapp/deque.svg?branch=master)](https://travis-ci.org/discordapp/deque)

[![Hex.pm Version](http://img.shields.io/hexpm/v/deque.svg?style=flat)](https://hex.pm/packages/deque)

Erlang only supports fast prepends to lists while appending requires a full copy. Getting the size of a list is also a

`O(n)` operation. This library implements a deque using two rotating lists to support fast append and prepend as well as

`O(1)` size via an internal counter.

## Features

- Bounded size

- `Enumerable` protocol

- `Collectable` protocol

- `Inspect` protocol

## Usage

Add it to `mix.exs`

```elixir

defp deps do

  [{:deque, "~> 1.0"}]

end

```

Then use it like other Elixir data structures.

```elixir

# Deque<[3, 2, 1]>

deque =

  Deque.new(5)

  |> Deque.appendleft(1)

  |> Deque.appendleft(2)

  |> Deque.appendleft(3)

# Deque<[2, 1]>

{3, deque} = Deque.popleft(deque)

# Deque<[6, 7, 8, 9, 10]>

Enum.into(0..10, Deque.new(5))

```

## License

Deque is released under [the MIT License](LICENSE).

Check [LICENSE](LICENSE) file for more information.