Telephone Words

telephone_words.rb

require "pp"

MAPPING = {
  1 => [],
  2 => %w(A B C),
  3 => %w(D E F),
  4 => %w(G H I),
  5 => %w(J K L),
  6 => %w(M N O),
  7 => %w(P Q R S),
  8 => %w(T U V),
  9 => %w(W X Y Z),
  0 => []
}.freeze

def telephoneWords(numbers)
  options = numbers.map { |n| MAPPING[n].clone }
  @results = []

  next_letter("", options.shift, options)

  puts @results
end

def next_letter(word, letters, rest)
  if rest.empty?
    letters.each { |l| @results << word + l }
    letters
  else
    letters.each do |l|
      r = rest.clone
      next_letter(word + l, r.shift, r)
    end
  end
end


def telephoneWords(numbers)
  options = numbers.map { |n| MAPPING[n].clone }

  nested_letters = next_letter(options.clone)
  pp nested_letters
end

def next_letter(rest)
  if rest.size == 1
    rest
  else
    r = rest.clone[1..-1]
    letters = Array(next_letter(r))

    rest.first.map do |l|
      [l] << letters
    end
  end
end

# [["D",
#   [["M", [["G", "H", "I"]]],
#    ["N", [["G", "H", "I"]]],
#    ["O", [["G", "H", "I"]]]]],
#  ["E",
#   [["M", [["G", "H", "I"]]],
#    ["N", [["G", "H", "I"]]],
#    ["O", [["G", "H", "I"]]]]],
#  ["F",
#   [["M", [["G", "H", "I"]]],
#    ["N", [["G", "H", "I"]]],
#    ["O", [["G", "H", "I"]]]]]]


def telephoneWords(numbers)
  options = numbers.map { |n| MAPPING[n].clone }

  puts next_letter("", options).flatten
end

def next_letter(path, rest)
  if rest.size == 1
    rest.flatten.map { |l| path + l }
  else
    rest.first.map do |l|
      r = rest.clone[1..-1]
      next_letter(path + l, r)
    end
  end
end


telephoneWords([3, 6, 4])