Merge branch 'master' of git://factorcode.org/git/factor

extra/project-euler/022/022.factor

@@ -1,6 +1,7 @@
 ! Copyright (c) 2007 Aaron Schaefer.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: ascii io.files kernel math project-euler.common sequences sorting splitting ;
+USING: ascii io.encodings.ascii io.files kernel math project-euler.common
+    sequences sequences.lib sorting splitting ;
 IN: project-euler.022
 
 ! http://projecteuler.net/index.php?section=problems&id=22
@@ -28,10 +29,10 @@ IN: project-euler.022
 
 : source-022 ( -- seq )
     "extra/project-euler/022/names.txt" resource-path
-    file-contents [ quotable? ] subset "," split ;
+    ascii file-contents [ quotable? ] subset "," split ;
 
 : name-scores ( seq -- seq )
-    dup length [ 1+ swap alpha-value * ] 2map ;
+    [ 1+ swap alpha-value * ] map-index ;
 
 PRIVATE>
 

extra/project-euler/047/047.factor

@@ -0,0 +1,96 @@
+! Copyright (c) 2008 Aaron Schaefer.
+! See http://factorcode.org/license.txt for BSD license.
+USING: arrays combinators.lib kernel math math.primes math.primes.factors
+    math.ranges namespaces sequences ;
+IN: project-euler.047
+
+! http://projecteuler.net/index.php?section=problems&id=47
+
+! DESCRIPTION
+! -----------
+
+! The first two consecutive numbers to have two distinct prime factors are:
+
+!     14 = 2 * 7
+!     15 = 3 * 5
+
+! The first three consecutive numbers to have three distinct prime factors are:
+
+!     644 = 2² * 7 * 23
+!     645 = 3 * 5 * 43
+!     646 = 2 * 17 * 19.
+
+! Find the first four consecutive integers to have four distinct primes
+! factors. What is the first of these numbers?
+
+
+! SOLUTION
+! --------
+
+! Brute force, not sure why it's incredibly slow compared to other languages
+
+<PRIVATE
+
+: (consecutive) ( count goal test -- n )
+    pick pick = [
+        swap - nip
+    ] [
+        dup prime? [ [ drop 0 ] dipd ] [
+            2dup unique-factors length = [ [ 1+ ] dipd ] [ [ drop 0 ] dipd ] if
+        ] if 1+ (consecutive)
+    ] if ;
+
+: consecutive ( goal test -- n )
+    0 -rot (consecutive) ;
+
+PRIVATE>
+
+: euler047 ( -- answer )
+    4 646 consecutive ;
+
+! [ euler047 ] time
+! 542708 ms run / 60548 ms GC time
+
+
+! ALTERNATE SOLUTIONS
+! -------------------
+
+! Use a sieve to generate prime factor counts up to an arbitrary limit, then
+! look for a repetition of the specified number of factors.
+
+<PRIVATE
+
+SYMBOL: sieve
+
+: initialize-sieve ( n -- )
+    0 <repetition> >array sieve set ;
+
+: is-prime? ( index -- ? )
+    sieve get nth zero? ;
+
+: multiples ( n -- seq )
+    sieve get length 1- over <range> ;
+
+: increment-counts ( n -- )
+     multiples [ sieve get [ 1+ ] change-nth ] each ;
+
+: prime-tau-upto ( limit -- seq )
+    dup initialize-sieve 2 swap [a,b) [
+        dup is-prime? [ increment-counts ] [ drop ] if
+    ] each sieve get ;
+
+: consecutive-under ( m limit -- n/f )
+    prime-tau-upto [ dup <repetition> ] dip start ;
+
+PRIVATE>
+
+: euler047a ( -- answer )
+    4 200000 consecutive-under ;
+
+! [ euler047a ] 100 ave-time
+! 503 ms run / 5 ms GC ave time - 100 trials
+
+! TODO: I don't like that you have to specify the upper bound, maybe try making
+! this lazy so it could also short-circuit when it finds the answer?
+
+MAIN: euler047a

extra/project-euler/059/059.factor

@@ -0,0 +1,92 @@
+! Copyright (c) 2008 Aaron Schaefer, Slava Pestov.
+! See http://factorcode.org/license.txt for BSD license.
+USING: arrays ascii assocs hashtables io.encodings.ascii io.files kernel math
+    math.parser namespaces sequences sequences.lib sequences.private sorting
+    splitting strings ;
+IN: project-euler.059
+
+! http://projecteuler.net/index.php?section=problems&id=59
+
+! DESCRIPTION
+! -----------
+
+! Each character on a computer is assigned a unique code and the preferred
+! standard is ASCII (American Standard Code for Information Interchange). For
+! example, uppercase A = 65, asterisk (*) = 42, and lowercase k = 107.
+
+! A modern encryption method is to take a text file, convert the bytes to
+! ASCII, then XOR each byte with a given value, taken from a secret key. The
+! advantage with the XOR function is that using the same encryption key on the
+! cipher text, restores the plain text; for example, 65 XOR 42 = 107, then 107
+! XOR 42 = 65.
+
+! For unbreakable encryption, the key is the same length as the plain text
+! message, and the key is made up of random bytes. The user would keep the
+! encrypted message and the encryption key in different locations, and without
+! both "halves", it is impossible to decrypt the message.
+
+! Unfortunately, this method is impractical for most users, so the modified
+! method is to use a password as a key. If the password is shorter than the
+! message, which is likely, the key is repeated cyclically throughout the
+! message. The balance for this method is using a sufficiently long password
+! key for security, but short enough to be memorable.
+
+! Your task has been made easy, as the encryption key consists of three lower
+! case characters. Using cipher1.txt (right click and 'Save Link/Target
+! As...'), a file containing the encrypted ASCII codes, and the knowledge that
+! the plain text must contain common English words, decrypt the message and
+! find the sum of the ASCII values in the original text.
+
+
+! SOLUTION
+! --------
+
+! Assume that the space character will be the most common, so XOR the input
+! text with a space character then group the text into three "columns" since
+! that's how long our key is.  Then do frequency analysis on each column to
+! find out what the most likely candidate is for the key.
+
+! NOTE: This technique would probably not work well in all cases, but luckily
+! it did for this particular problem.
+
+<PRIVATE
+
+: source-059 ( -- seq )
+    "extra/project-euler/059/cipher1.txt" resource-path
+    ascii file-contents [ blank? ] right-trim "," split
+    [ string>number ] map ;
+
+TUPLE: rollover seq n ;
+
+C: <rollover> rollover
+
+M: rollover length rollover-n ;
+
+M: rollover nth-unsafe rollover-seq [ length mod ] keep nth-unsafe ;
+
+INSTANCE: rollover immutable-sequence
+
+: decrypt ( seq key -- seq )
+    over length <rollover> swap [ bitxor ] 2map ;
+
+: frequency-analysis ( seq -- seq )
+    dup prune [
+        [ 2dup [ = ] curry count 2array , ] each
+    ] { } make nip ; inline
+
+: most-frequent ( seq -- elt )
+    frequency-analysis sort-values keys peek ;
+
+: crack-key ( seq key-length -- key )
+    [ " " decrypt ] dip group 1 head-slice*
+    flip [ most-frequent ] map ;
+
+PRIVATE>
+
+: euler059 ( -- answer )
+    source-059 dup 3 crack-key decrypt sum ;
+
+! [ euler059 ] 100 ave-time
+! 13 ms run / 0 ms GC ave time - 100 trials
+
+MAIN: euler059

extra/project-euler/059/cipher1.txt

@@ -0,0 +1 @@
+79,59,12,2,79,35,8,28,20,2,3,68,8,9,68,45,0,12,9,67,68,4,7,5,23,27,1,21,79,85,78,79,85,71,38,10,71,27,12,2,79,6,2,8,13,9,1,13,9,8,68,19,7,1,71,56,11,21,11,68,6,3,22,2,14,0,30,79,1,31,6,23,19,10,0,73,79,44,2,79,19,6,28,68,16,6,16,15,79,35,8,11,72,71,14,10,3,79,12,2,79,19,6,28,68,32,0,0,73,79,86,71,39,1,71,24,5,20,79,13,9,79,16,15,10,68,5,10,3,14,1,10,14,1,3,71,24,13,19,7,68,32,0,0,73,79,87,71,39,1,71,12,22,2,14,16,2,11,68,2,25,1,21,22,16,15,6,10,0,79,16,15,10,22,2,79,13,20,65,68,41,0,16,15,6,10,0,79,1,31,6,23,19,28,68,19,7,5,19,79,12,2,79,0,14,11,10,64,27,68,10,14,15,2,65,68,83,79,40,14,9,1,71,6,16,20,10,8,1,79,19,6,28,68,14,1,68,15,6,9,75,79,5,9,11,68,19,7,13,20,79,8,14,9,1,71,8,13,17,10,23,71,3,13,0,7,16,71,27,11,71,10,18,2,29,29,8,1,1,73,79,81,71,59,12,2,79,8,14,8,12,19,79,23,15,6,10,2,28,68,19,7,22,8,26,3,15,79,16,15,10,68,3,14,22,12,1,1,20,28,72,71,14,10,3,79,16,15,10,68,3,14,22,12,1,1,20,28,68,4,14,10,71,1,1,17,10,22,71,10,28,19,6,10,0,26,13,20,7,68,14,27,74,71,89,68,32,0,0,71,28,1,9,27,68,45,0,12,9,79,16,15,10,68,37,14,20,19,6,23,19,79,83,71,27,11,71,27,1,11,3,68,2,25,1,21,22,11,9,10,68,6,13,11,18,27,68,19,7,1,71,3,13,0,7,16,71,28,11,71,27,12,6,27,68,2,25,1,21,22,11,9,10,68,10,6,3,15,27,68,5,10,8,14,10,18,2,79,6,2,12,5,18,28,1,71,0,2,71,7,13,20,79,16,2,28,16,14,2,11,9,22,74,71,87,68,45,0,12,9,79,12,14,2,23,2,3,2,71,24,5,20,79,10,8,27,68,19,7,1,71,3,13,0,7,16,92,79,12,2,79,19,6,28,68,8,1,8,30,79,5,71,24,13,19,1,1,20,28,68,19,0,68,19,7,1,71,3,13,0,7,16,73,79,93,71,59,12,2,79,11,9,10,68,16,7,11,71,6,23,71,27,12,2,79,16,21,26,1,71,3,13,0,7,16,75,79,19,15,0,68,0,6,18,2,28,68,11,6,3,15,27,68,19,0,68,2,25,1,21,22,11,9,10,72,71,24,5,20,79,3,8,6,10,0,79,16,8,79,7,8,2,1,71,6,10,19,0,68,19,7,1,71,24,11,21,3,0,73,79,85,87,79,38,18,27,68,6,3,16,15,0,17,0,7,68,19,7,1,71,24,11,21,3,0,71,24,5,20,79,9,6,11,1,71,27,12,21,0,17,0,7,68,15,6,9,75,79,16,15,10,68,16,0,22,11,11,68,3,6,0,9,72,16,71,29,1,4,0,3,9,6,30,2,79,12,14,2,68,16,7,1,9,79,12,2,79,7,6,2,1,73,79,85,86,79,33,17,10,10,71,6,10,71,7,13,20,79,11,16,1,68,11,14,10,3,79,5,9,11,68,6,2,11,9,8,68,15,6,23,71,0,19,9,79,20,2,0,20,11,10,72,71,7,1,71,24,5,20,79,10,8,27,68,6,12,7,2,31,16,2,11,74,71,94,86,71,45,17,19,79,16,8,79,5,11,3,68,16,7,11,71,13,1,11,6,1,17,10,0,71,7,13,10,79,5,9,11,68,6,12,7,2,31,16,2,11,68,15,6,9,75,79,12,2,79,3,6,25,1,71,27,12,2,79,22,14,8,12,19,79,16,8,79,6,2,12,11,10,10,68,4,7,13,11,11,22,2,1,68,8,9,68,32,0,0,73,79,85,84,79,48,15,10,29,71,14,22,2,79,22,2,13,11,21,1,69,71,59,12,14,28,68,14,28,68,9,0,16,71,14,68,23,7,29,20,6,7,6,3,68,5,6,22,19,7,68,21,10,23,18,3,16,14,1,3,71,9,22,8,2,68,15,26,9,6,1,68,23,14,23,20,6,11,9,79,11,21,79,20,11,14,10,75,79,16,15,6,23,71,29,1,5,6,22,19,7,68,4,0,9,2,28,68,1,29,11,10,79,35,8,11,74,86,91,68,52,0,68,19,7,1,71,56,11,21,11,68,5,10,7,6,2,1,71,7,17,10,14,10,71,14,10,3,79,8,14,25,1,3,79,12,2,29,1,71,0,10,71,10,5,21,27,12,71,14,9,8,1,3,71,26,23,73,79,44,2,79,19,6,28,68,1,26,8,11,79,11,1,79,17,9,9,5,14,3,13,9,8,68,11,0,18,2,79,5,9,11,68,1,14,13,19,7,2,18,3,10,2,28,23,73,79,37,9,11,68,16,10,68,15,14,18,2,79,23,2,10,10,71,7,13,20,79,3,11,0,22,30,67,68,19,7,1,71,8,8,8,29,29,71,0,2,71,27,12,2,79,11,9,3,29,71,60,11,9,79,11,1,79,16,15,10,68,33,14,16,15,10,22,73

extra/project-euler/project-euler.factor

@@ -13,10 +13,11 @@ USING: definitions io io.files kernel math math.parser project-euler.ave-time
     project-euler.033 project-euler.034 project-euler.035 project-euler.036
     project-euler.037 project-euler.038 project-euler.039 project-euler.040
     project-euler.041 project-euler.042 project-euler.043 project-euler.044
-    project-euler.045 project-euler.046 project-euler.048 project-euler.052
+    project-euler.045 project-euler.046 project-euler.047 project-euler.048
-    project-euler.053 project-euler.056 project-euler.067 project-euler.075
+    project-euler.052 project-euler.053 project-euler.056 project-euler.059
-    project-euler.079 project-euler.092 project-euler.097 project-euler.134
+    project-euler.067 project-euler.075 project-euler.079 project-euler.092
-    project-euler.169 project-euler.173 project-euler.175 ;
+    project-euler.097 project-euler.134 project-euler.169 project-euler.173
+    project-euler.175 ;
 IN: project-euler
 
 <PRIVATE