Ruby

def palindrome?(string)
    letters = string.downcase.scan(/\w/)
    return letters == letters.reverse
end

palindrome?("A man, a plan, a canal -- Panama")  # => true
palindrome?("Madam, I'm Adam!")                  # => true
palindrome?("Abracadabra")                       # => false (nil is also ok)

def count_words(string)
    words = string.downcase.split(/[^a-zA-Z]/).reject{|e| e.empty?}
    wf = Hash.new(0)
    words.each { |word| wf[word] += 1 }
    return wf
end
count_words("A man, a plan, a canal -- Panama")
    # => {'a' => 3, 'man' => 1, 'canal' => 1, 'panama' => 1, 'plan' => 1}
count_words "Doo bee doo bee doo"
    # => {'doo' => 3, 'bee' => 2}

class WrongNumberOfPlayersError <  StandardError ; end
class NoSuchStrategyError <  StandardError ; end
 
def rps_game_winner(game)
    raise WrongNumberOfPlayersError unless game.length == 2
    s0 = game[0][1].upcase
    s1 = game[1][1].upcase
    raise NoSuchStrategyError unless ["R", "S", "P"].include? s0
    raise NoSuchStrategyError unless ["R", "S", "P"].include? s1
    if ( s0 == s1) 
        return game[0]
    end
    if (s0 == "R")
		return (s1 == "S" ? game[0] : game[1])
    elsif (s0 == "S") 
		return (s1 == "P" ? game[0] : game[1])
	else
		return (s1 == "R" ? game[0] : game[1])
    end
end

rps_game_winner([ ["Armando", "P"], ["Dave", "S"] ])

def rps_tournament_winner(tournament)
   s0 = tournament[0][1]
   if (s0.is_a? String) 
      return rps_game_winner(tournament)
   else
      return rps_game_winner([rps_tournament_winner(tournament[0]), rps_tournament_winner(tournament[1])])
   end
end
rps_tournament_winner([
    [
        [ ["Armando", "P"], ["Dave", "S"] ],
        [ ["Richard", "R"],  ["Michael", "S"] ],
    ],
    [
        [ ["Allen", "S"], ["Omer", "P"] ],
        [ ["David E.", "R"], ["Richard X.", "P"] ]
    ]
])

def combine_anagrams(words)
    hash = Hash.new()
    words.each do |word|
        sorted_word = word.downcase.split('').sort.join
        if hash.has_key?(sorted_word)
            hash.store(sorted_word, hash.fetch(sorted_word).push(word))
        else
            hash.store(sorted_word, Array.new(1,word))
        end
    end
    return hash.values
end

combine_anagrams(['cars', 'for', 'potatoes', 'racs', 'four', 'scar', 'creams', 'scream'])

class Dessert
    attr_accessor :name
    attr_accessor :calories
    def initialize(name, calories)
        # Your code here
    end

    def healthy?
        if (calories < 200) 
		    return true
		else 
		    return false
		end
    end

    def delicious?
        return true
    end
end

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