Hello,
I forked your gist and made some changes: http://gist.github.com/274956
The main change is use foldl' instead of explicit recursion (HLint may
point this out.) This gives us clearness and strictness.
And It runs faster than ruby's one on my 2GHz MacBook =)
I used ruby-1.9.1 for ruby interpreter, and GHC-6.12.1 for haskell compiler.
time ruby ./anagram.rb < /usr/share/dict/words
[["caret", "carte", "cater", "crate", "creat", "creta", "react",
"recta", "trace"], ["ester", "estre", "reest", "reset", "steer",
"stere", "stree", "terse", "tsere"], ["angor", "argon", "goran",
"grano", "groan", "nagor", "orang", "organ", "rogan"]]
real 0m4.620s
user 0m4.473s
sys 0m0.150s
ghc --make anagram
time ./anagram < /usr/share/dict/words
[["caret","carte","cater","crate","creat","creta","react","recta","trace"],["angor","argon","goran","grano","groan","nagor","orang","organ","rogan"],["ester","estre","reest","reset","steer","stere","stree","terse","tsere"]]
real 0m3.797s
user 0m3.613s
sys 0m0.173s
Each output is slightly different because of spec of Hash in ruby 1.9.
see also:
http://www.igvita.com/2009/02/04/ruby-19-internals-ordered-hash/
http://hackage.haskell.org/packages/archive/containers/0.2.0.1/doc/html/Data...
Cheers
-- nwn
On Tue, Jan 12, 2010 at 10:22 AM, Joe Van Dyk
I've written two versions of the same program, one in ruby and one in haskell. Given words on stdin, find all the anagrams in those words. For nicer display, we're only going to display the top 3 results.
I'm obviously new to haskell. The ruby version runs about 5x as fast on a large file. How can I improve the haskell version?
# Ruby version input = STDIN.read.split("\n") result = Hash.new([]) input.each do |word| sorted_word = word.split('').sort.join result[sorted_word] += [word] end values = result.values.sort { |a, b| b.size <=> a.size } p values[0..3]
# Haskell version import List import qualified Data.Map as Map
-- Given as stdin -- presents -- serpents -- no -- on -- whatever -- Expected Output: -- [["serpents","presents"],["on","no"]]
-- This version only displays words that have more than one -- match in the list, and sorts by the words that got the most matches.
-- Can we do the map bit better?
main = do input <- getContents print $ anagrams $ lines input
anagrams words = sorted_anagrams where sorted_anagrams = sortBy sorter filtered_anagrams sorter a b = compare (length b) (length a) filtered_anagrams = Map.elems $ Map.filter filter_function all_anagrams filter_function words = length words > 1 all_anagrams = do_anagrams words Map.empty do_anagrams [] result = result do_anagrams words result = do_anagrams (tail words) (Map.unionWith (++) (Map.fromList [(sorted_current_word, [current_word])]) result) where current_word = head words sorted_current_word = sort current_word
-- Joe Van Dyk http://fixieconsulting.com _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners