From: Brian Adkins <lojicdotcom@...>
Date: 2007-10-20T09:40:03+09:00
Subject: Re: combinations listing

Program 1: create the hash and dump to disk for future use

words = Hash.new([])

File.open("dictionary.txt", "r") do |file|
  while line = file.gets
    word = line.chomp
    words[word.split('').sort!.join('')] += [word]
  end
end

File.open("word_hash", "w") do |file|
  Marshal.dump(words, file)
end

Program 2: load the hash from disk to solve anagrams

words = nil

File.open("word_hash", "r") do |file|
  words = Marshal.load(file)
end

while true
  print "Enter word: "
  anagram = gets.chomp
  sorted_anagram = anagram.split('').sort!.join('')
  p  words[sorted_anagram]
end
---

This is pretty darn fast, so unless your dictionary is huge, I'd
probably skip the step of partitioning the dictionary by word size. I
used a 70K word dictionary and the dumped hash was 1.5MB.

Since strings are mutable in Ruby, I tried sorting the string using a
quicksort algorithm instead of "split, sort, join", but since the
former was in Ruby and the latter mostly in C, the latter is *much*
faster. This speed disparity encourages taking an indirect route at
times.

Maybe some C extension guru can supply an example of extending the
String class with a sort! method :)

Brian Adkins