114 lines
2.8 KiB
Factor
114 lines
2.8 KiB
Factor
! Copyright (C) 2007 Ryan Murphy, Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: kernel math sequences arrays assocs ;
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IN: heaps
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<PRIVATE
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TUPLE: heap data ;
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: <heap> ( class -- heap )
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>r V{ } clone heap construct-boa r>
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construct-delegate ; inline
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PRIVATE>
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TUPLE: min-heap ;
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: <min-heap> ( -- min-heap ) min-heap <heap> ;
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TUPLE: max-heap ;
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: <max-heap> ( -- max-heap ) max-heap <heap> ;
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<PRIVATE
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: left ( n -- m ) 2 * 1+ ; inline
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: right ( n -- m ) 2 * 2 + ; inline
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: up ( n -- m ) 1- 2 /i ; inline
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: left-value ( n heap -- obj ) >r left r> nth ; inline
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: right-value ( n heap -- obj ) >r right r> nth ; inline
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: up-value ( n vec -- obj ) >r up r> nth ; inline
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: swap-up ( n vec -- ) >r dup up r> exchange ; inline
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: last-index ( vec -- n ) length 1- ; inline
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GENERIC: heap-compare ( pair1 pair2 heap -- ? )
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: (heap-compare) drop [ first ] compare 0 ; inline
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M: min-heap heap-compare (heap-compare) > ;
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M: max-heap heap-compare (heap-compare) < ;
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: heap-bounds-check? ( m heap -- ? )
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heap-data length >= ; inline
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: left-bounds-check? ( m heap -- ? )
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>r left r> heap-bounds-check? ; inline
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: right-bounds-check? ( m heap -- ? )
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>r right r> heap-bounds-check? ; inline
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: up-heap-continue? ( vec heap -- ? )
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>r [ last-index ] keep [ up-value ] keep peek r>
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heap-compare ; inline
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: up-heap ( vec heap -- )
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2dup up-heap-continue? [
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>r dup last-index [ over swap-up ] keep
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up 1+ head-slice r> up-heap
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] [
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2drop
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] if ;
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: (child) ( m heap -- n )
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dupd
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[ heap-data left-value ] 2keep
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[ heap-data right-value ] keep heap-compare
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[ right ] [ left ] if ;
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: child ( m heap -- n )
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2dup right-bounds-check? [ drop left ] [ (child) ] if ;
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: swap-down ( m heap -- )
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[ child ] 2keep heap-data exchange ;
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DEFER: down-heap
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: down-heap-continue? ( heap m heap -- m heap ? )
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[ heap-data nth ] 2keep child pick
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dupd [ heap-data nth swapd ] keep heap-compare ;
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: (down-heap) ( m heap -- )
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2dup down-heap-continue? [
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-rot [ swap-down ] keep down-heap
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] [
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3drop
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] if ;
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: down-heap ( m heap -- )
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2dup left-bounds-check? [ 2drop ] [ (down-heap) ] if ;
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PRIVATE>
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: heap-push ( value key heap -- )
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>r swap 2array r>
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[ heap-data push ] keep
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[ heap-data ] keep
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up-heap ;
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: heap-push-all ( assoc heap -- )
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[ swapd heap-push ] curry assoc-each ;
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: heap-peek ( heap -- value key )
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heap-data first first2 swap ;
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: heap-pop* ( heap -- )
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dup heap-data length 1 > [
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[ heap-data pop ] keep
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[ heap-data set-first ] keep
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0 swap down-heap
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] [
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heap-data pop*
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] if ;
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: heap-pop ( heap -- value key ) dup heap-peek rot heap-pop* ;
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: heap-empty? ( heap -- ? ) heap-data empty? ;
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: heap-length ( heap -- n ) heap-data length ;
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