Created
October 13, 2015 08:22
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module PriorityQueue where | |
import Data.Map (Map) | |
import qualified Data.Map as Map | |
data Unique = U | |
instance Eq Unique where | |
U == U = False | |
instance Ord Unique where | |
compare U U = LT | |
data PriorityQueue k v = PriorityQueue (v -> k) (Map (k, Unique) v) | |
-- instance (Ord k, Show k, Show v) => Show (PriorityQueue k v) where | |
-- show (PriorityQueue _ m) = "PriorityQueue\n" ++ | |
-- unlines (map (\(k, U) -> "\t" ++ show (m Map.! k) ++ " -> " ++ show k) keys) | |
-- where keys = Map.keys m | |
empty :: Ord k => (v -> k) -> PriorityQueue k v | |
empty k = PriorityQueue k Map.empty | |
insert :: Ord k => v -> PriorityQueue k v -> PriorityQueue k v | |
insert v (PriorityQueue k m) = PriorityQueue k (Map.insert (k v, U) v m) | |
findMin :: Ord k => PriorityQueue k v -> (k, v) | |
findMin (PriorityQueue _ m) = let ((k, _), v) = Map.findMin m in (k, v) | |
deleteMin :: Ord k => PriorityQueue k v -> PriorityQueue k v | |
deleteMin (PriorityQueue k m) = PriorityQueue k (Map.deleteMin m) | |
minView :: Ord k => PriorityQueue k v -> ((k, v), PriorityQueue k v) | |
minView p = (findMin p, deleteMin p) | |
size :: Ord k => PriorityQueue k v -> Int | |
size (PriorityQueue _ m) = Map.size m | |
null :: Ord k => PriorityQueue k v -> Bool | |
null (PriorityQueue _ m) = Map.null m |
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