# `heaps`

This library defines a heap protocol and provides minimum and maximum heaps using two different implementations: pairing heaps and binary heaps.

The heap representations should be regarded as opaque terms, subjected to be changed without notice, and only accessed using the library predicates.

For backward-compatibility, the `legacy.lgt` file defines the `heapp` protocol extending the `heap_protocol` protocol plus the `heap/1`, `minheap`, and `maxheap` objects extending the `binary_heap/1` object. These legacy protocol and objects are deprecated and should not be used in new code.

## API documentation

Open the ../../apis/library_index.html#heaps link in a web browser.

## Loading

To load all entities in this library, load the `loader.lgt` file:

    | ?- logtalk_load(heaps(loader)).

## Testing

To test this library predicates, load the `tester.lgt` file:

    | ?- logtalk_load(heaps(tester)).

## Usage

Choose the heap implementation that best suits your needs. The pairing heap implementation is usually the best choice, specially if insertion and merging operations dominate in your use case. You can easily benchmark and compare the two implementations using either a `uses/2` directive with a parameter variable for the heap object and calling the heap predicates using implicit message-sending goals or a `uses/1` directive defining an object alias for the heap object and using the alias with explicit message-sending goals.

The two main library objects are `binary_heap(Order)` and `pairing_heap(Order)`, where `Order` is either `<` for a minimum heap or `>` for a maximum heap. For convenience, there are also `binary_heap_min` and `pairing_heap_min` objects for minimum heaps and `binary_heap_max` and `pairing_heap_max` objects for maximum heaps.

## Credits

Original binary heap code by Richard O’Keefe and adapted to Logtalk by Paulo Moura and Victor Lagerkvist.