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module RabbitPopulation (progressTime) where
import Data.List (sort)
import Debug.Trace (traceShow)
-- Data
type Age = Int
type Months = Int
type GrowthRate = Int
data RabbitPair = RabbitPair Age deriving (Eq, Ord)
instance Show RabbitPair where
show (RabbitPair age) =
if age > 0 then "rr" ++ show age else "bb" ++ show age
-- Operations
makeBabies :: Int -> [RabbitPair]
makeBabies 0 = []
makeBabies numToMake = (RabbitPair 0) : makeBabies (numToMake - 1)
numberAdults :: [RabbitPair] -> Int
numberAdults pairs = length $ filter (\(RabbitPair age) -> age > 0) pairs
ageRabbits :: [RabbitPair] -> [RabbitPair]
ageRabbits = map (\(RabbitPair age) -> RabbitPair (age + 1))
growPop :: GrowthRate -> [RabbitPair] -> [RabbitPair]
growPop growthRate pairs =
(makeBabies (growthRate * (numberAdults pairs)))
progressTime :: Months -> GrowthRate -> [RabbitPair] -> [RabbitPair]
progressTime 1 growthRate rabbits = rabbits
progressTime months growthRate rabbits =
traceShow rabbits $
progressTime (months - 1) growthRate ((ageRabbits rabbits) ++ newborns)
where newborns = growPop growthRate rabbits
main = do
print $ progressTime 6 1 [(RabbitPair 0)]
Haskell
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