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Update solution to Project Euler problem 92

db4
Aaron Schaefer 2008-02-09 22:40:18 -05:00
parent a34c5aabed
commit 9c2218a1c4
1 changed files with 7 additions and 8 deletions
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extra/project-euler/092/092.factor
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@ -1,7 +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: combinators.lib kernel math math.ranges namespaces project-euler.common USING: kernel math math.ranges project-euler.common sequences ;
sequences ;
IN: project-euler.092 IN: project-euler.092
! http://projecteuler.net/index.php?section=problems&id=92 ! http://projecteuler.net/index.php?section=problems&id=92
@ -30,7 +29,7 @@ IN: project-euler.092
<PRIVATE <PRIVATE
: next-link ( n -- m ) : next-link ( n -- m )
number>digits [ sq ] sigma ; 0 swap [ dup zero? not ] [ 10 /mod sq -rot [ + ] dip ] [ ] while drop ;
: chain-ending ( n -- m ) : chain-ending ( n -- m )
dup 1 = over 89 = or [ next-link chain-ending ] unless ; dup 1 = over 89 = or [ next-link chain-ending ] unless ;
@ -41,15 +40,15 @@ IN: project-euler.092
: fast-chain-ending ( seq n -- m ) : fast-chain-ending ( seq n -- m )
dup 567 > [ next-link ] when 1- swap nth ; 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> PRIVATE>
: euler092 ( -- answer ) : euler092 ( -- answer )
lower-endings 9999999 [1,b] [ fast-chain-ending 89 = ] with count ; lower-endings 9999999 [1,b] [ fast-chain-ending 89 = ] with count ;
! [ euler092 ] time ! [ euler092 ] 10 ave-time
! 68766 ms run / 372 ms GC time ! 11169 ms run / 0 ms GC ave time - 10 trials
! TODO: solution is still too slow, maybe try using a 10000000-byte array that
! keeps track of each number in the chain and their endings
MAIN: euler092 MAIN: euler092