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Optimize solution to Project Euler problem 27

db4
Aaron Schaefer 2008-01-17 12:55:02 -05:00
parent 9c78c7c05f
commit a02ee715c1
1 changed files with 7 additions and 2 deletions
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extra/project-euler/027/027.factor
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@ -36,10 +36,15 @@ IN: project-euler.027
! SOLUTION
! --------
! b must be prime since n = 0 must return a prime
! a + b + 1 must be prime since n = 1 must return a prime
! a < b
<PRIVATE
: source-027 ( -- seq )
1000 [ prime? ] subset dup [ neg ] map append dup cartesian-product ;
1000 [ prime? ] subset [ dup [ neg ] map append ] keep
cartesian-product [ first2 < ] subset ;
: quadratic ( b a n -- m )
dup sq -rot * + + ;
@ -60,7 +65,7 @@ PRIVATE>
source-027 max-consecutive drop product ;
! [ euler027 ] 100 ave-time
! 1306 ms run / 58 ms GC ave time - 100 trials
! 687 ms run / 23 ms GC ave time - 100 trials
! TODO: generalize max-consecutive/max-product (from #26) into a new word