zt日記

✑ [ruby] 第22回 Ruby/Rails勉強会＠関西のアレ

問題4のしりとりをやってみたもの。実行時には入力にあわせて-Kオプションの指定が必要。

#!/usr/bin/ruby
$longest = 0 # ugly
def siritori(selected_words, rest_words)
  word = selected_words[-1]
  if word
    last_char = word[/.$/]
    next_words = rest_words.grep(/^#{last_char}/) # TODO: Regexp.escape
  else
    next_words = rest_words # first call
  end
  if next_words.empty?
    if selected_words.size >= $longest
      $longest = selected_words.size
      p [selected_words.size, selected_words]
    end
  else
    next_words.each do |next_word|
      siritori(selected_words + [next_word], rest_words - [next_word])
    end
  end
end
words = $<.read.split(/\W/)
p [words.size, words]
siritori([], words)