Priority Queue implementation.

The nested modules contain multiple different implementations for priority queues.

This module can be used to dispatch to them. The used implementation can be altered as a configuration setting, to allow for the most efficient implementation for your application.

Examples

iex> pqueue = (
iex> Prioqueue.empty()
iex> |> Prioqueue.insert(10)
iex> |> Prioqueue.insert(20)
iex> |> Prioqueue.insert(15)
iex> |> Prioqueue.insert(100)
iex> )
#Prioqueue.Implementations.SkewHeap<[10, 15, 20, 100]>
iex> Prioqueue.member?(pqueue, 20)
true
iex> {:ok, {item, pqueue_rest}} = Prioqueue.extract_min(pqueue)
iex> item
10
iex> pqueue_rest
#Prioqueue.Implementations.SkewHeap<[15, 20, 100]>

Protocols

The various Prioqueue Implementations implement the following protocols:

Collectable

which allows transforming a collection into a Prioqueue.

iex> Enum.into([1,2,3,4], Prioqueue.empty())
#Prioqueue.Implementations.SkewHeap<[1, 2, 3, 4]>

Enumerable

which allows transforming a Prioqueue into another collection.

iex> pqueue = Enum.into([1, 2, 3, 10, 5, 2], Prioqueue.empty())
#Prioqueue.Implementations.SkewHeap<[1, 2, 2, 3, 5, 10]>
iex> Enum.map(pqueue, fn x -> x * 2 end)
[2, 4, 4, 6, 10, 20]

FunLand.Reducable

which allows the reduction of a Prioqueue into some other value.

iex> pqueue = Enum.into([1, 2, 3, 10, 5, 2], Prioqueue.empty())
iex> FunLand.Reducable.reduce(pqueue, 0, fn acc, x -> acc + x end)
23

FunLand.Combinable

which allows to merge two Prioqueues together.

iex> pqueue = Enum.into([1, 3, 5], Prioqueue.empty())
iex> pqueue2 = Enum.into([1, 2, 3, 4], Prioqueue.empty())
iex> FunLand.Combinable.combine(pqueue, pqueue2)
#Prioqueue.Implementations.SkewHeap<[1, 1, 2, 3, 3, 4, 5]>

Extractable

which allows extracting a single element from the Prioqueue.

iex> Extractable.extract(Prioqueue.empty())
{:error, :empty}

iex> pqueue = Enum.into([1, 3, 5], Prioqueue.empty())
iex> {:ok, {item, pqueue_rest}} = Extractable.extract(pqueue)
iex> item
1
iex> pqueue_rest
#Prioqueue.Implementations.SkewHeap<[3, 5]>

Insertable

which allows inserting a single element into the Prioqueue.

iex> {:ok, pqueue} = Insertable.insert(Prioqueue.empty(), 4)
iex> pqueue
#Prioqueue.Implementations.SkewHeap<[4]>

Configuration settings

The behaviour of Prioqueue can be altered per call by passing options to new, or by writing down application-wide configuration options for the application :prioqueue:

• :default_implementation: The Priority Queue implementation to use.
• :default_comparison_function: The comparison function that should be used to keep the Priority Queue ordered.