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@zeedunk
Created September 10, 2010 05:53
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require '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.
#
# 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.
class AboutScoringAssignment < EdgeCase::Koan
def score(dice)
total_score = 0
[2,3,4,6].each do |number|
total_score += score_for_number(dice, number, number * 100, 0)
end
total_score += score_for_number(dice, 5, 500, 50)
total_score += score_for_number(dice, 1, 1000, 100)
end
def score_for_number(dice, selection, value_of_triple, value_of_single)
selected = dice.select{|item| item == selection}
three_or_more = selected.size >= 3
remaining = three_or_more ? selected[3, selected.size] : selected
remaining.inject(three_or_more ? value_of_triple : 0){|total, item| total + value_of_single}
end
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_mulitple_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_more_than_triple_others_is_still_100x
assert_equal 200, score([2,2,2,2])
assert_equal 300, score([3,3,3,3,3])
assert_equal 400, score([4,4,4,4])
assert_equal 600, score([6,6,6,6])
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])
end
end
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zeedunk commented Sep 10, 2010

@youngnh - Thanks for the feedback. I think that would certainly be a simplification and I'll start hacking on that as soon as I get a chance.

@benjaminplee - I agree that the code doesn't clearly express why five and one are special cases. Integrating that with Nate's suggestion will be a fun challenge. As far the last inject, well, I keep reaching for inject because it's my new favorite toy. :) You're right though, it is unnecessary there.

Thanks again guys!

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