! Copyright (c) 2008 Aaron Schaefer.
! See http://factorcode.org/license.txt for BSD license.
-USING: kernel math math.functions math.primes math.ranges sequences ;
+USING: kernel math math.functions math.primes math.ranges
+sequences project-euler.common math.bitwise ;
IN: project-euler.046
! http://projecteuler.net/index.php?section=problems&id=46
2 /i sqrt >integer [1,b] [ sq ] map ;
: fits-conjecture? ( n -- ? )
- dup perfect-squares [ 2 * - ] with map [ prime? ] contains? ;
+ dup perfect-squares [ 2 * - ] with map [ prime? ] any? ;
: next-odd-composite ( n -- m )
- dup odd? [ 2 + ] [ 1+ ] if dup prime? [ next-odd-composite ] when ;
+ dup odd? [ 2 + ] [ 1 + ] if dup prime? [ next-odd-composite ] when ;
: disprove-conjecture ( n -- m )
dup fits-conjecture? [ next-odd-composite disprove-conjecture ] when ;
9 disprove-conjecture ;
! [ euler046 ] 100 ave-time
-! 150 ms run / 2 ms GC ave time - 100 trials
+! 37 ms ave run time - 3.39 SD (100 trials)
-MAIN: euler046
+SOLUTION: euler046