Thanks to Jordi who found a testcase that broke my code I reworked the solution. Now I use a different approach to skipping numbers. I create the possible skips for a given number, ignore the skipped numbers, search a real solution for the rest and reinject the skipped numbers into the solution.
That is a lot nicer, and also the code is now cleaner. Additionally I
improved loading of the wordlist once again, made -v a true verbose
switch and added abit of description.
I hope I'm not annoying people with this long posts.
As always: The nice and colorfull solutions is at:
http://ruby.brian-schroeder.de/quiz/phoneword/
or directly at
http://ruby.brian-schroeder.de/quiz/phoneword/browse/phoneword-rb.html
Best regards,
Brian
#!/usr/bin/ruby
# Nodes in the Dictionary.
class DictionaryNode < Array
# Terminal info
attr_reader :words
def initialize
super(10)
@words =
end
end
# A tree-indexed version of the dictionary that allows efficent searching by number 2 alphabet mapping.
class Dictionary
def initialize(encoding)
super()
@encoding = {}
@inverse_encoding = {}
encoding.each do | k, v |
@encoding[k] = v.split(/\s+/).map{|c| c[0]}
end
# Create map from characters to numbers
@inverse_encoding = @encoding.inject({}) { | r, (k, v) |
v.each do | l | r[l] = k end
r
}
@root = DictionaryNode.new
end
# Helper method for rekursive adding of words to the dictionary
private
def add_recursive(node, word, position)
if word.length == position
node.words << word
return node
end
add_recursive(node[@inverse_encoding[word[position]]] ||= DictionaryNode.new, word, position + 1)
end
# Add words to the dictionary
public
def add(word)
add_recursive(@root, word, 0)
self
end
# Load a wordlist from a file, which contains one word per line.
# Ignores punctuation and whitespace.
def load_wordlist(file, options)
$stderr.print "Loading dictionary... " if options.verbose
start = Time.new
file.read.gsub(/[^A-Za-z\n]/, '').upcase!.split($/).uniq!.each do |w|
w.chomp!
next if w.empty? or w.length <= options.min_length
self.add(w)
end
$stderr.puts "built dictionary in %f seconds" % (Time.new-start).to_f if options.verbose
self
end
private
# Search words and return (in the block) words and the unmatched rest of the number
def sub_find(node, number, &block)
# Return words found so far
block[node.words.map{|w|w.dup}, number] unless node.words.empty?
# No more digits, so stop searching here
return node if number.empty?
# Search for longer words
sub_find(node[number[0]], number[1..-1], &block) if node[number[0]]
end
private
# Calculate all allowed skip patterns for a number of a given length
def skips(s, length)
return [s] if length == 0
result = skips(s + [false], length-1)
result.concat(skips(s + [true], length-1)) unless s[-1]
result
end
public
# Skipping makes this a bit ugly
def find_noskip(number)
result =
sub_find(@root, number) do | words, rest_number |
if rest_number.empty?
result.concat(words)
else
find_noskip(rest_number).each do | sentence |
words.each do | w |
result << w + '-' + sentence
end
end
end
end
result
end
# Skipping makes this a bit ugly
def find(number)
result =
skips(, number.length).each do | skipped |
# Create the injector that can inject the skipped numbers back into the word
injector =
skipped.zip(number).each_with_index do |(s,n), i|
injector << [n.to_s, i] if s
end
# We search for words built from the unskipped digits
unskipped_digits = number.zip(skipped).select{|(d, s)| !s}.map{|(d,s)|d}
sentences = find_noskip(unskipped_digits)
# Inject the skipped digits back into the found sentences
sentences.each do | s |
injector.each do | (n, i) | s.insert(i, n) end
end
result.concat(sentences)
end
result
end
end
encodings = {
:james => {
2 => 'A B C',
3 => 'D E F',
4 => 'G H I',
5 => 'J K L',
6 => 'M N O',
7 => 'P Q R S',
8 => 'T U V',
9 => 'W X Y Z'},
:logic => {
0 => 'A B',
1 => 'C D',
2 => 'E F',
3 => 'G H',
4 => 'I J K',
5 => 'L M N',
6 => 'O P Q',
7 => 'R S T',
8 => 'U V W',
9 => 'X Y Z'
}
}
require 'optparse'
class PhonewordOptions < OptionParser
attr_reader :dictionary, :encoding, :format, :allow_skips, :help, :encoding_help, :verbose, :min_length
def initialize
super()
@dictionary = '/usr/share/dict/words'
@encoding = :james
@format = :plain
@allow_skips = true
@help = false
@encoding_help = false
@verbose = false
@ignore_non_alpha = false
@min_length = 1
self.on("-d", "--dictionary DICTIONARY", String) { | v | @dictionary = v }
self.on("-e", "--encoding ENCODING", String,
"How the alphabet is encoded to phonenumbers. james or logic are supported.") { | v | @encoding = v.downcase.to_sym }
self.on("-p", "--plain", 'One result per found number, no other information. (Default)') { @format = :plain }
self.on("-f", "--full", 'Prefix the result with the number') { @format = :full }
self.on("-v", "--verbose", 'Make more noise') { @verbose = true }
self.on("-s", "--skips", "--allow_skips", "--allow-skips", 'Allow to skip one adjacent number while matching. (Default)',
'Gives lots of ugly results, but james asked for it.') { @allow_skips = true }
self.on("-c", "--no-skips", "Don't leave numbers in the detected words") { @allow_skips = false }
self.on("-m" "--min-length", "Minimum length of accepted words.",
"Use this to ignore one-letter words that make the output quite uninteresting.", Integer) { | v | @min_length = v }
self.on("-?", "--help") { @help = true }
self.on("--supported-encodings", "--encoding-help", "List the supported encodings") { @encoding_help = true }
end
end
options = PhonewordOptions.new
begin
options.parse!(ARGV)
rescue => e
puts e
puts options
exit
end
if options.help
puts options
exit
end
if options.encoding_help or !encodings[options.encoding]
puts "Possible encodings:"
puts encodings.to_a.sort_by{|(k,v)|k.to_s}.map{|(k,v)| "#{k}:\n"+v.map{|(n,e)|" #{n}: #{e}"}.sort.join("\n")}
exit
end
dictionary = Dictionary.new(encodings[options.encoding]).load_wordlist(File.open(options.dictionary), options)
output = {
:plain => lambda do | number, sentence | sentence end,
:full => lambda do | number, sentence | "#{number.ljust(15)}: #{sentence}" end }
method = {true => :find, false => :find_noskip }
ARGF.each do | number |
number.strip!
number = number.gsub(/[^0-9]/, '').unpack('C*').map{|n|n - ?0}
$stderr.puts "Searching for #{number}" if options.verbose
dictionary.send(method[options.allow_skips], number).each do | sentence |
puts output[options.format][number, sentence]
end
end
···
On Tue, 22 Feb 2005 16:59:02 +0900 Brian Schröder <ruby.brian@gmail.com> wrote:
Hello Jordi,
you found a bug. Your number makes my code enter into an infinite
loop. I'll fix it and repost.
Thanks,
Brian
On Tue, 22 Feb 2005 06:26:16 +0900, Jordi Bunster <jordi@bunster.org> wrote:
>
> On Feb 20, 2005, at 3:50 PM, Brian Schröder wrote:
>
> > This version loads the dictionary a lot faster (3 times as fast as the
> > old
> > version) because it does not create as many intermediate objects. Also
> > I measured that upcasing and gsub'ing is faster on the long string
> > than on the individual short strings.
>
> Must be something wrong with my old iBook, because here it takes
> aaaaages for anything to even appear.
>
> Makes me wonder if I'm running it correctly:
>
> echo 5467945 | ruby phoneword.rb -v -p -s -d /usr/share/dict/words
>
> Or is the problem just that I/O intensive?
>
> --
> Jordi
>
>
