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April 24, 2015 12:42
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Greed Dice Game solution
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# 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. | |
def score(dice) | |
score = 0 | |
results = Hash.new | |
for x in 1..6 do | |
results[x] = [] | |
end | |
for d in dice do | |
results[d].push(d) | |
end | |
for key in results.keys do | |
if results[key].length >= 3 | |
if key == 1 | |
score = 1000 | |
else | |
score = 100 * key | |
end | |
end | |
end | |
score += (results[1].length % 3) * 100 | |
score += (results[5].length % 3) * 50 | |
return score | |
end |
I might have done something like this:
def score(dice)
(1..6).inject(0) do |score, d|
multiplier = d == 1 ? 10 : 1
count = dice.select { |die| die == d }.count
if count >= 3
score += (d * multiplier * 100)
count -= 3
end
if d == 1 || d == 5
score += (multiplier * count * d * 10)
end
score
end
end
Ah - I hadn't thought about abstracting the multiplier.
Also, I was unaware of passing multiple variables into the do
sandwich. I would have a hard time remembering whether d
was assigned to the (1..6)
or score
.
May I also mention that mutating score on each iteration seems like a Haskel thang.
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Omit
return
except to short circuit a procedureRuby implicitly returns the value of the last expression in the method.
Instead of
do
score
In your particular example, ending the method with the following will suffice: