Given the number of points earned in a football game, determine all the possible scoring sequences

football.rb

# name: human-readable name
# point_value: number of points earned
# priority: how likely the score is to actually happen
ScoreType = Struct.new(:name, :point_value, :priority)

SCORE_TYPES = [
  ScoreType.new('safety', 2, 5),
  ScoreType.new('field goal', 3, 2),
  ScoreType.new('touchdown', 6, 3),
  ScoreType.new('touchdown with extra point', 7, 1),
  ScoreType.new('touchdown with 2-point conversion', 8, 4)
]

def possible_scoring_sequences_for(points, current_sequence)
  return [current_sequence] if points == 0

  SCORE_TYPES.each_with_object([]) do |score_type, ret|
    if points >= score_type.point_value
      ret.concat(
        possible_scoring_sequences_for(
          points - score_type.point_value, current_sequence + [score_type]
        )
      )
    end
  end
end

sequences = possible_scoring_sequences_for(ARGV[0].to_i, [])
  .map { |seq| seq.sort { |a, b| a.name <=> b.name } }.uniq
  .sort do |a, b|
    a_priority = a.inject(0) { |ret, score_type| ret + score_type.priority }
    b_priority = b.inject(0) { |ret, score_type| ret + score_type.priority }
    a_priority <=> b_priority
  end

sequences.each do |sequence|
  puts sequence.map(&:name).join(', ')
end