23 lignes
657 B
Haskell
23 lignes
657 B
Haskell
module QueueEx where
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import Control.Applicative
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import Data.Dequeue (BankersDequeue)
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import qualified Data.Dequeue as Q
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-- |Shift a queue to the left, such as:
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-- [1, 2, 3] -> [2, 3, 1]
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shiftQueueLeft :: BankersDequeue a -> BankersDequeue a
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shiftQueueLeft = (\(Just (b, nq)) -> Q.pushBack nq b) <$> Q.popFront
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-- |Shift a queue to the right, such as:
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-- [1, 2, 3] -> [3, 1, 2]
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shiftQueueRight :: BankersDequeue a -> BankersDequeue a
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shiftQueueRight = (\(Just (b, nq)) -> Q.pushFront nq b) <$> Q.popBack
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-- |Convert a Queue back to a list.
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queueToList :: BankersDequeue a -> [a]
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queueToList q = Q.takeFront (length q) q
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