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faster implementation of euler023 using a hashtable

db4
Jon Harper 2009-09-30 23:08:45 +09:00
parent 9210a9a79c
commit f65ffc6640
1 changed files with 5 additions and 8 deletions
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extra/project-euler/023/023.factor
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@ -1,6 +1,6 @@
! Copyright (c) 2008 Aaron Schaefer. ! Copyright (c) 2008 Aaron Schaefer.
! See http://factorcode.org/license.txt for BSD license. ! See http://factorcode.org/license.txt for BSD license.
USING: kernel math math.ranges project-euler.common sequences sets sorting ; USING: kernel math math.ranges project-euler.common sequences sets sorting assocs fry ;
IN: project-euler.023 IN: project-euler.023
! http://projecteuler.net/index.php?section=problems&id=23 ! http://projecteuler.net/index.php?section=problems&id=23
@ -42,10 +42,9 @@ IN: project-euler.023
[1,b] [ abundant? ] filter ; [1,b] [ abundant? ] filter ;
: possible-sums ( seq -- seq ) : possible-sums ( seq -- seq )
dup { } -rot [ H{ } clone
dupd [ + ] curry map [ dupd '[ _ [ + _ conjoin ] with each ] each ]
rot append prune swap rest keep keys ;
] each drop natural-sort ;
PRIVATE> PRIVATE>
@ -53,9 +52,7 @@ PRIVATE>
source-023 source-023
20161 abundants-upto possible-sums diff sum ; 20161 abundants-upto possible-sums diff sum ;
! TODO: solution is still too slow, although it takes under 1 minute
! [ euler023 ] time ! [ euler023 ] time
! 52780 ms run / 3839 ms GC ! 2.15542 seconds
SOLUTION: euler023 SOLUTION: euler023