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@tehviking
Created April 10, 2011 06:25
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Ruby Dice Koan after some help from friends; knocked about 20 lines off & cured some fragility.
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.
#
# 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)
score = 0
counts = count_dice(dice)
triples = check_for_triples(dice)
if triples == 1
score += 1000
elsif triples
score += (triples * 100)
end
counts[triples] -= 3
score += counts[1] * 100 if counts[1]
score += counts[5] * 50 if counts[5]
end
def count_dice(dice)
dice.inject(Hash.new(0)) { |count, die| count[die] += 1; count }
end
def check_for_triples(dice)
(1..6).detect { |i| dice.select { |j| j==i }.size >= 3 }
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
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