factor: trim using lists

[factor.git] / extra / project-euler / 049 / 049.factor

diff --git a/extra/project-euler/049/049.factor b/extra/project-euler/049/049.factor
index 15dd7ed6d2edfd1b6210b441af5ffb858d24f3b8..0594b8b0395bfdbbee5a1f163f54b67940f009c4 100644 (file)
--- a/extra/project-euler/049/049.factor
+++ b/extra/project-euler/049/049.factor
@@ -1,7 +1,8 @@
 ! Copyright (c) 2009 Aaron Schaefer.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: arrays byte-arrays fry hints kernel math math.combinatorics
-    math.functions math.parser math.primes project-euler.common sequences sets ;
+USING: arrays kernel math math.primes project-euler.common
+sequences sets ;
+FROM: project-euler.common => permutations? ;
 IN: project-euler.049
 
 ! http://projecteuler.net/index.php?section=problems&id=49
@@ -25,16 +26,6 @@ IN: project-euler.049
 
 <PRIVATE
 
-: count-digits ( n -- byte-array )
-    10 <byte-array> [
-        '[ 10 /mod _ [ 1+ ] change-nth dup 0 > ] loop drop
-    ] keep ;
-
-HINTS: count-digits fixnum ;
-
-: permutations? ( n m -- ? )
-    [ count-digits ] bi@ = ;
-
 : collect-permutations ( seq -- seq )
     [ V{ } clone ] [ dup ] bi* [
         dupd '[ _ permutations? ] filter
@@ -50,7 +41,7 @@ HINTS: count-digits fixnum ;
 
 : (find-unusual-terms) ( n seq -- seq/f )
     [ [ arithmetic-terms ] with map ] keep
-    '[ _ [ peek ] dip member? ] find nip ;
+    '[ _ [ last ] dip member? ] find nip ;
 
 : find-unusual-terms ( seq -- seq/? )
     unclip-slice over (find-unusual-terms) [