#lang scribble/manual @(require "helper.rkt") @(require unstable/scribble) @defmodule/this-package[skewbinomialheap] @(require (for-label (planet krhari/pfds:1:0/skewbinomialheap))) @(require scribble/eval) @(define evaluate (make-base-eval)) @(evaluate '(require typed/racket)) @(evaluate '(require "skewbinomialheap.ss")) @title[#:tag "skewbh"]{Skew Binomial Heap} Skew Binomial Heaps are Binomial Heaps with hybrid numerical representation for heaps based on both skew binary numbers. Skew binary number representation is used since incrementing a skew binary number is quick and simple. Provides worst case running time of @bold{@italic{O(log(n))}} for the operations @scheme[find-min/max], @scheme[delete-min/max] and @scheme[merge]. And worst case running time of @bold{@italic{O(1)}} for the @scheme[insert] operation. @defform[(Heap A)]{A skew binomial heap of type @racket[A].} @defproc[(heap [comp (A A -> Boolean)] [a A] ...) (Heap A)]{ Function @scheme[heap] creates a Skew Binomial Heap with the given inputs. @examples[#:eval evaluate (heap < 1 2 3 4 5 6) ] In the above example, the binomial heap obtained will have elements 1 thru' 6 with < as the comparison function.} @defproc[(empty? [heap (Heap A)]) Boolean]{ Function @scheme[empty?] checks if the given binomial heap is empty or not. @examples[#:eval evaluate (empty? (heap < 1 2 3 4 5 6)) (empty? (heap <)) ]} @defproc[(insert [a A] [heap (Heap A)] ...) (Heap A)]{ Function @scheme[insert] takes an element and a binomial heap and inserts the given element into the binomial heap. @examples[#:eval evaluate (insert 10 (heap < 1 2 3 4 5 6)) ] In the above example, insert adds the element 10 to @scheme[(heap < 1 2 3 4 5 6)].} @defproc[(find-min/max [heap (Heap A)]) A]{ Function @scheme[find-min/max] takes a binomial heap and gives the largest or the smallest element in the heap if binomial heap is not empty else throws an error. The element returned is max or min depends on the comparison function of the heap. @examples[#:eval evaluate (find-min/max (heap < 1 2 3 4 5 6)) (find-min/max (heap > 1 2 3 4 5 6)) (find-min/max (heap <)) ]} @defproc[(delete-min/max [heap (Heap A)]) (Heap A)]{ Function @scheme[delete-min/max] takes a binomial heap and returns the same heap with out the min or max element in the given heap. The element removed from the heap is max or min depends on the comparison function of the heap. @examples[#:eval evaluate (delete-min/max (heap < 1 2 3 4 5 6)) (delete-min/max (heap > 1 2 3 4 5 6)) (delete-min/max (heap <)) ] In the above example, @scheme[(delete-min/max (heap < 1 2 3 4 5 6))] deletes 1 and returns @scheme[(delete-min/max (heap < 2 3 4 5 6))]. And @scheme[(delete-min/max (heap > 1 2 3 4 5 6))] deletes 6 and returns @scheme[(delete-min/max (heap < 1 2 3 4 5))].} @defproc[(merge [bheap1 (Heap A)] [bheap2 (Heap A)]) (Heap A)]{ Function @scheme[merge] takes two binomial heaps and returns a merged binomial heap. Uses the comparison function in the first heap for merging and the same function becomes the comparison function for the merged heap. @margin-note{If the comparison functions do not have the same properties, merged heap might lose its heap-order.} @examples[#:eval evaluate (define bheap1 (heap < 1 2 3 4 5 6)) (define bheap2 (heap (λ: ([a : Integer] [b : Integer]) (< a b)) 10 20 30 40 50 60)) (merge bheap1 bheap2) ] In the above example, @scheme[(merge bheap1 bheap2)], merges the heaps and < will become the comparison function for the merged heap.} @defproc[(sorted-list [heap (Heap A)]) (Listof A)]{ Function @scheme[sorted-list] takes a binomial heap and returns a list which is sorted according to the comparison function of the heap. @examples[#:eval evaluate (sorted-list (heap > 1 2 3 4 5 6)) (sorted-list (heap < 1 2 3 4 5 6)) ]} @defproc[(map [comparer (C C -> Boolean)] [func (A B ... B -> C)] [hep1 (Heap A)] [hep2 (Heap B)] ...) (Heap A)]{ Function @scheme[map] is similar to @|racket-map| for lists. @examples[#:eval evaluate (sorted-list (map < add1 (heap < 1 2 3 4 5 6))) (sorted-list (map < * (heap < 1 2 3 4 5 6) (heap < 1 2 3 4 5 6))) ]} @defproc[(fold [func (C A B ... B -> C)] [init C] [hep1 (Heap A)] [hep2 (Heap B)] ...) C]{ Function @scheme[fold] is similar to @|racket-foldl| or @|racket-foldr| @margin-note{@scheme[fold] currently does not produce correct results when the given function is non-commutative.} @examples[#:eval evaluate (fold + 0 (heap < 1 2 3 4 5 6)) (fold * 1 (heap < 1 2 3 4 5 6) (heap < 1 2 3 4 5 6)) ]} @defproc[(filter [func (A -> Boolean)] [hep (Heap A)]) (Heap A)]{ Function @scheme[filter] is similar to @|racket-filter|. @examples[#:eval evaluate (define hep (heap < 1 2 3 4 5 6)) (sorted-list (filter (λ: ([x : Integer]) (> x 5)) hep)) (sorted-list (filter (λ: ([x : Integer]) (< x 5)) hep)) (sorted-list (filter (λ: ([x : Integer]) (<= x 5)) hep)) ]} @defproc[(remove [func (A -> Boolean)] [hep (Heap A)]) (Heap A)]{ Function @scheme[remove] is similar to @|racket-filter| but @scheme[remove] removes the elements which match the predicate. @examples[#:eval evaluate (sorted-list (remove (λ: ([x : Integer]) (> x 5)) (heap < 1 2 3 4 5 6))) (sorted-list (remove (λ: ([x : Integer]) (< x 5)) (heap < 1 2 3 4 5 6))) (sorted-list (remove (λ: ([x : Integer]) (<= x 5)) (heap < 1 2 3 4 5 6))) ]} @defproc[(andmap [func (A B ... B -> Boolean)] [heap1 (Heap A)] [heap2 (Heap B)] ...) Boolean]{ Function @scheme[andmap] is similar to @|racket-andmap|. @examples[#:eval evaluate (andmap even? (heap < 1 2 3 4 5 6)) (andmap odd? (heap < 1 2 3 4 5 6)) (andmap positive? (heap < 1 2 3 4 5 6)) (andmap negative? (heap < -1 -2)) ]} @defproc[(ormap [func (A B ... B -> Boolean)] [heap1 (Heap A)] [heap2 (Heap B)] ...) Boolean]{ Function @scheme[ormap] is similar to @|racket-ormap|. @examples[#:eval evaluate (ormap even? (heap < 1 2 3 4 5 6)) (ormap odd? (heap < 1 2 3 4 5 6)) (ormap positive? (heap < -1 -2 3 4 -5 6)) (ormap negative? (heap < 1 -2)) ]} @defproc[(build-heap [size Natural] [func (Natural -> A)] [comp (A A -> Boolean)]) (Heap A)]{ Function @scheme[build-heap] is similar to @|racket-build-list| but this function takes an extra comparison function. @examples[#:eval evaluate (sorted-list (build-heap 5 (λ:([x : Integer]) (add1 x)) <)) (sorted-list (build-heap 5 (λ:([x : Integer]) (* x x)) <)) ]} @(close-eval evaluate)