| Copyright | (c) Louis Wasserman 2010 |
|---|---|
| License | BSD-style |
| Maintainer | libraries@haskell.org |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell2010 |
Data.PQueue.Max
Contents
Description
General purpose priority queue, supporting view-maximum operations.
An amortized running time is given for each operation, with n referring to the length of the sequence and k being the integral index used by some operations. These bounds hold even in a persistent (shared) setting.
This implementation is based on a binomial heap augmented with a global root.
The spine of the heap is maintained lazily. To force the spine of the heap,
use seqSpine.
This implementation does not guarantee stable behavior.
This implementation offers a number of methods of the form xxxU, where U stands for
unordered. No guarantees whatsoever are made on the execution or traversal order of
these functions.
- data MaxQueue a
- empty :: MaxQueue a
- null :: MaxQueue a -> Bool
- size :: MaxQueue a -> Int
- findMax :: MaxQueue a -> a
- getMax :: MaxQueue a -> Maybe a
- deleteMax :: Ord a => MaxQueue a -> MaxQueue a
- deleteFindMax :: Ord a => MaxQueue a -> (a, MaxQueue a)
- delete :: Ord a => MaxQueue a -> Maybe (MaxQueue a)
- maxView :: Ord a => MaxQueue a -> Maybe (a, MaxQueue a)
- singleton :: a -> MaxQueue a
- insert :: Ord a => a -> MaxQueue a -> MaxQueue a
- insertBehind :: Ord a => a -> MaxQueue a -> MaxQueue a
- union :: Ord a => MaxQueue a -> MaxQueue a -> MaxQueue a
- unions :: Ord a => [MaxQueue a] -> MaxQueue a
- (!!) :: Ord a => MaxQueue a -> Int -> a
- take :: Ord a => Int -> MaxQueue a -> [a]
- drop :: Ord a => Int -> MaxQueue a -> MaxQueue a
- splitAt :: Ord a => Int -> MaxQueue a -> ([a], MaxQueue a)
- takeWhile :: Ord a => (a -> Bool) -> MaxQueue a -> [a]
- dropWhile :: Ord a => (a -> Bool) -> MaxQueue a -> MaxQueue a
- span :: Ord a => (a -> Bool) -> MaxQueue a -> ([a], MaxQueue a)
- break :: Ord a => (a -> Bool) -> MaxQueue a -> ([a], MaxQueue a)
- filter :: Ord a => (a -> Bool) -> MaxQueue a -> MaxQueue a
- partition :: Ord a => (a -> Bool) -> MaxQueue a -> (MaxQueue a, MaxQueue a)
- mapMaybe :: Ord b => (a -> Maybe b) -> MaxQueue a -> MaxQueue b
- mapEither :: (Ord b, Ord c) => (a -> Either b c) -> MaxQueue a -> (MaxQueue b, MaxQueue c)
- map :: (a -> b) -> [a] -> [b]
- foldrAsc :: Ord a => (a -> b -> b) -> b -> MaxQueue a -> b
- foldlAsc :: Ord a => (b -> a -> b) -> b -> MaxQueue a -> b
- foldrDesc :: Ord a => (a -> b -> b) -> b -> MaxQueue a -> b
- foldlDesc :: Ord a => (b -> a -> b) -> b -> MaxQueue a -> b
- toList :: Ord a => MaxQueue a -> [a]
- toAscList :: Ord a => MaxQueue a -> [a]
- toDescList :: Ord a => MaxQueue a -> [a]
- fromList :: Ord a => [a] -> MaxQueue a
- fromAscList :: [a] -> MaxQueue a
- fromDescList :: [a] -> MaxQueue a
- mapU :: (a -> b) -> MaxQueue a -> MaxQueue b
- foldrU :: (a -> b -> b) -> b -> MaxQueue a -> b
- foldlU :: (b -> a -> b) -> b -> MaxQueue a -> b
- elemsU :: MaxQueue a -> [a]
- toListU :: MaxQueue a -> [a]
- keysQueue :: MaxPQueue k a -> MaxQueue k
- seqSpine :: MaxQueue a -> b -> b
Documentation
A priority queue with elements of type a. Supports extracting the maximum element.
Implemented as a wrapper around MinQueue.
Basic operations
Query operations
findMax :: MaxQueue a -> a Source #
O(1). Returns the maximum element of the queue. Throws an error on an empty queue.
getMax :: MaxQueue a -> Maybe a Source #
O(1). The top (maximum) element of the queue, if there is one.
deleteMax :: Ord a => MaxQueue a -> MaxQueue a Source #
O(log n). Deletes the maximum element of the queue. Does nothing on an empty queue.
deleteFindMax :: Ord a => MaxQueue a -> (a, MaxQueue a) Source #
O(log n). Extracts the maximum element of the queue. Throws an error on an empty queue.
delete :: Ord a => MaxQueue a -> Maybe (MaxQueue a) Source #
O(log n). Delete the top (maximum) element of the sequence, if there is one.
maxView :: Ord a => MaxQueue a -> Maybe (a, MaxQueue a) Source #
O(log n). Extract the top (maximum) element of the sequence, if there is one.
Construction operations
insert :: Ord a => a -> MaxQueue a -> MaxQueue a Source #
O(1). Insert an element into the priority queue.
insertBehind :: Ord a => a -> MaxQueue a -> MaxQueue a Source #
Amortized O(1), worst-case O(log n). Insert an element into the priority queue, putting it behind elements that compare equal to the inserted one.
union :: Ord a => MaxQueue a -> MaxQueue a -> MaxQueue a Source #
O(log (min(n1,n2))). Take the union of two priority queues.
Subsets
Extracting subsets
(!!) :: Ord a => MaxQueue a -> Int -> a Source #
O(k log n). Returns the (k+1)th largest element of the queue.
take :: Ord a => Int -> MaxQueue a -> [a] Source #
O(k log n). Returns the list of the k largest elements of the queue, in descending order, or
all elements of the queue, if k >= n.
drop :: Ord a => Int -> MaxQueue a -> MaxQueue a Source #
O(k log n). Returns the queue with the k largest elements deleted, or the empty queue if k >= n.
splitAt :: Ord a => Int -> MaxQueue a -> ([a], MaxQueue a) Source #
O(k log n). Equivalent to (take k queue, drop k queue).
Predicates
takeWhile :: Ord a => (a -> Bool) -> MaxQueue a -> [a] Source #
takeWhile, applied to a predicate p and a queue queue, returns the
longest prefix (possibly empty) of queue of elements that satisfy p.
span :: Ord a => (a -> Bool) -> MaxQueue a -> ([a], MaxQueue a) Source #
span, applied to a predicate p and a queue queue, returns a tuple where
first element is longest prefix (possibly empty) of queue of elements that
satisfy p and second element is the remainder of the queue.
break :: Ord a => (a -> Bool) -> MaxQueue a -> ([a], MaxQueue a) Source #
break, applied to a predicate p and a queue queue, returns a tuple where
first element is longest prefix (possibly empty) of queue of elements that
do not satisfy p and second element is the remainder of the queue.
Filter/Map
filter :: Ord a => (a -> Bool) -> MaxQueue a -> MaxQueue a Source #
O(n). Returns a queue of those elements which satisfy the predicate.
partition :: Ord a => (a -> Bool) -> MaxQueue a -> (MaxQueue a, MaxQueue a) Source #
O(n). Returns a pair of queues, where the left queue contains those elements that satisfy the predicate, and the right queue contains those that do not.
mapMaybe :: Ord b => (a -> Maybe b) -> MaxQueue a -> MaxQueue b Source #
O(n). Maps a function over the elements of the queue, and collects the Just values.
Fold/Functor/Traversable variations
map :: (a -> b) -> [a] -> [b] #
map f xs is the list obtained by applying f to each element
of xs, i.e.,
map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn] map f [x1, x2, ...] == [f x1, f x2, ...]
foldrDesc :: Ord a => (a -> b -> b) -> b -> MaxQueue a -> b Source #
O(n log n). Performs a right-fold on the elements of a priority queue in descending order.
foldlDesc :: Ord a => (b -> a -> b) -> b -> MaxQueue a -> b Source #
O(n log n). Performs a left-fold on the elements of a priority queue in descending order.
List operations
toList :: Ord a => MaxQueue a -> [a] Source #
O(n log n). Returns the elements of the priority queue in ascending order. Equivalent to toDescList.
If the order of the elements is irrelevant, consider using toListU.
toAscList :: Ord a => MaxQueue a -> [a] Source #
O(n log n). Extracts the elements of the priority queue in ascending order.
toDescList :: Ord a => MaxQueue a -> [a] Source #
O(n log n). Extracts the elements of the priority queue in descending order.
fromList :: Ord a => [a] -> MaxQueue a Source #
O(n log n). Constructs a priority queue from an unordered list.
fromAscList :: [a] -> MaxQueue a Source #
O(n). Constructs a priority queue from an ascending list. Warning: Does not check the precondition.
fromDescList :: [a] -> MaxQueue a Source #
O(n). Constructs a priority queue from a descending list. Warning: Does not check the precondition.
Unordered operations
mapU :: (a -> b) -> MaxQueue a -> MaxQueue b Source #
O(n). Assumes that the function it is given is monotonic, and applies this function to every element of the priority queue. Does not check the precondition.
foldrU :: (a -> b -> b) -> b -> MaxQueue a -> b Source #
O(n). Unordered right fold on a priority queue.
foldlU :: (b -> a -> b) -> b -> MaxQueue a -> b Source #
O(n). Unordered left fold on a priority queue.
toListU :: MaxQueue a -> [a] Source #
O(n). Returns a list of the elements of the priority queue, in no particular order.