about_scoring_project.rb

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

# Greed is a dice game where you roll up to five dice to accumulate
# points.  The following "score" function will be used to calculate the
# score of a single roll of the dice.
#
# 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.

##### My original answer

# def score(dice)
#   # You need to write this method
#   score = 0
#   array = dice.sort
#   # A set of three ones is 1000 points
#   if array.count(1) >= 3
#     score += 1000
#     array = array.drop(3)
#   end
#   # A set of three numbers (other than ones) is worth 100 times the number
#   for digit in 2..6
#    if array.count(digit) >= 3
#     score += 100 * digit
#     set = array.select { |num|  num == digit }
#     set = set.drop(3)
#     array = array.drop_while {|num| num == digit }
#     array = array + set
#    end
#   end
#   # 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.
#   array.each do |i|
#     score += 100 if i == 1
#     score += 50 if i == 5
#   end
#   score
# end

##### Better version

def score(dice)
  result = 0
  scores = Hash.new 0

  dice.each do |n|
    scores[n] += 1
  end

  scores.each do |key, value|
    triplets, remainer = value / 3, value % 3

    result += (100 * remainer) + (1000 * triplets) if key == 1
    result += (50 * remainer) + (500 * triplets) if key == 5
    result += (100 * key) if (key != 1 && key != 5 && value >= 3)
  end

  result
end

class AboutScoringProject < Neo::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])
    assert_equal 1100, score([1,1,1,1])
    assert_equal 1200, score([1,1,1,1,1])
    assert_equal 1150, score([1,1,1,5,1])
  end

end