about_scoring_project.rb

require File.expand_path(File.dirname(__FILE__) + '/edgecase')

# Greed is a dice game where you roll up to five dice to accumulate
# points.  The following "score" function will be used calculate the
# score of a single roll of the dice.
#
# ASSUMPTIONS:
#   -- Dice is six sided with sides 1,2,3,4,5,6.
#   -- a greed roll can have any number of rolls.
#   -- In a greed roll of more than 3 individual rolls, the 'sets of three' noted
#      are mutually exclusive.  A greed roll of [1,1,1,1] == 1100 not 2000.
 
# A greed roll is scored as follows:
#
# * A set of three ones is 1000 points
#
# * A set of three numbers (other than ones) is worth 100 times the
#   number. (e.g. three fives is 500 points).
#
# * A one (that is not part of a set of three) is worth 100 points.
#
# * A five (that is not part of a set of three) is worth 50 points.
#
# * Everything else is worth 0 points.
#
#
# Examples:
#
# score([1,1,1,5,1]) => 1150 points
# score([2,3,4,6,2]) => 0 points
# score([3,4,5,3,3]) => 350 points
# score([1,5,1,2,4]) => 250 points
#
# More scoring examples are given in the tests below:
#
# Your goal is to write the score method.

def score(dice)
  # First score dice array based on length.
  case dice.length
  when 0
    return 0
  when 1,2
    return score_short_roll(dice)
  else
    return score_long_roll(dice)
  end
end

def score_short_roll(dice)
  dice.inject(0) { |score, die| score += score_one_roll(die) }
end 

def score_one_roll(die)
    score = 0
    case die
    when 1
      score = 100
    when 5
      score = 50
    end
    score
end

def score_long_roll(dice)
  score_sides_seen(get_sides_seen(dice))
end

def get_sides_seen(dice)
  sides_seen = [0,0,0,0,0,0] 
  dice.each do |die|
    sides_seen[die-1] += 1    
  end
  sides_seen
end

def score_sides_seen(sides_seen)
  score = 0
  sides_seen.each_with_index do |rolls, index| 
    side = index + 1
    if rolls > 0
      if rolls >= 3 
        if side == 1
          score += 1000
        else
          score += side * 100 * (rolls / 3).floor
        end
      end 
      (rolls % 3).times do |roll|
        score += score_one_roll(side)
      end
    end
  end
  score
end

class AboutScoringProject < EdgeCase::Koan
  def test_score_of_an_empty_list_is_zero
    assert_equal 0, score([])
  end

  def test_score_of_a_single_roll_of_5_is_50
    assert_equal 50, score([5])
  end

  def test_score_of_a_single_roll_of_1_is_100
    assert_equal 100, score([1])
  end

  def test_score_of_multiple_1s_and_5s_is_the_sum_of_individual_scores
    assert_equal 300, score([1,5,5,1])
  end

  def test_score_of_single_2s_3s_4s_and_6s_are_zero
    assert_equal 0, score([2,3,4,6])
  end

  def test_score_of_a_triple_1_is_1000
    assert_equal 1000, score([1,1,1])
  end

  def test_score_of_other_triples_is_100x
    assert_equal 200, score([2,2,2])
    assert_equal 300, score([3,3,3])
    assert_equal 400, score([4,4,4])
    assert_equal 500, score([5,5,5])
    assert_equal 600, score([6,6,6])
  end

  def test_score_of_mixed_is_sum
    assert_equal 250, score([2,5,2,2,3])
    assert_equal 550, score([5,5,5,5])
  end

end