Cleanup of Project Euler problem 92

db4
Aaron Schaefer 2008-11-03 18:25:50 -05:00
parent b13b120244
commit 9152b6d5f0
1 changed files with 5 additions and 6 deletions

View File

@ -1,6 +1,6 @@
! Copyright (c) 2008 Aaron Schaefer, Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: kernel math math.ranges sequences ;
USING: kernel math math.ranges project-euler.common sequences ;
IN: project-euler.092
! http://projecteuler.net/index.php?section=problems&id=92
@ -29,7 +29,7 @@ IN: project-euler.092
<PRIVATE
: next-link ( n -- m )
0 swap [ dup zero? not ] [ 10 /mod sq -rot [ + ] dip ] [ ] while drop ;
number>digits [ sq ] sigma ;
: chain-ending ( n -- m )
dup [ 1 = ] [ 89 = ] bi or [ next-link chain-ending ] unless ;
@ -40,15 +40,14 @@ IN: project-euler.092
: fast-chain-ending ( seq n -- m )
dup 567 > [ next-link ] when 1- swap nth ;
: count ( seq quot -- n )
0 -rot [ rot >r call [ r> 1+ ] [ r> ] if ] curry each ; inline
PRIVATE>
: euler092 ( -- answer )
lower-endings 9999999 [1,b] [ fast-chain-ending 89 = ] with count ;
! [ euler092 ] 10 ave-time
! 11169 ms run / 0 ms GC ave time - 10 trials
! 33257 ms ave run time - 624.27 SD (10 trials)
! TODO: this solution is not very efficient, much better optimizations exist
MAIN: euler092