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Binary heap.


(require-extension binary-heap)


The binary-heap library is based on the Ocaml heap implementation by Jean-Christophe Filliatre.

Heaps are encoded as binary trees that have the heap property, namely the value of any node is greater or equal than the nodes in its left and right subtrees.

A binary-heap object is created by procedure make-binary-heap, the only user-visible procedure defined in this egg:

[procedure] make-binary-heap:: KEY-COMPARE-PROC -> SELECTOR

where KEY-COMPARE-PROC is a user-supplied function that takes two keys and returns a negative, positive, or zero number depending on how the first key compares to the second.

The returned selector procedure can take one of the following arguments:

'get-max returns a (key . value) pair for an association in the heap with the largest key. If the heap is empty, an error is signalled.
'delete-max removes the max key and the corresponding association from the heap. Returns a (key . value) pair of the removed association. If the heap is empty, an error is signalled.
'empty? returns #t if the heap is empty
'size returns the size (the number of associations) in the heap
'put pure variant of PUT!; it returns a new heap object that contains the given association, while the original heap object is unmodified.
'for-each returns a procedure LAMBDA PROC that will apply the given procedure PROC to each (key . value) association of the heap, from the one with the smallest key all the way to the one with the max key, in an ascending order of keys.
'fold returns a procedure LAMBDA PROC INITIAL such that, given the associations in the heap ordered by the descending order of keys: (key-n . value-n) ... (key-2 . value-2) (key-1 . value-1) the procedure returns the result of the successive function applications (PROC value-1 (PROC value-2 ... (PROC value-n INITIAL).


About this egg


Ivan Raikov

Version history

Documentation converted to wiki format
Initial release


Copyright 2007-2010 Ivan Raikov.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
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