gistfile1.rb

module Abbreviator

  def self.abbreviate(names)
    abbrs = names.sort.inject({}) do |hash, name|
      hash[name] = replace_non_word_chars(name).slice(0,3)
      hash
    end
    Hash[*abbrs.map do |name, abbr|
      [name,
        (abbrs.values.select{|v|v.eql?(abbr)}.size == 1) ? abbr :
              resolve_conflict(abbr, name, [abbrs.select{|k,v| v.eql?(abbr)}.map(&:first)-[name]].flatten)]
    end.flatten]
  end

  private

    def self.replace_non_word_chars(s)
      s.gsub(/\W/, '')
    end

    def self.resolve_conflict(abbr, name, conflicts)
      conflict_chars = conflicts.map {|c| replace_non_word_chars(c).split('')}
      abbr + (replace_non_word_chars(name).split('').detect do |char|
        !conflict_chars.map {|c| c.shift}.include?(char)
      end || '')
    end

end