Data.PurePriorityQueue

A pure priority queue.

Because many function names clash with Prelude names, this module is usually imported qualified, e.g.,

  import qualified Data.PurePriorityQueue as PQ

This implementation is built on top of Data.Map.

Estimates of worst-case time complexity are given. The value n is the number of elements in the queue. The value p is the cardinality of the set of priorities of the elements in the queue. p is never greater than n.

Documentation

data MinMaxQueue p a

A queue of values of type a with priority of type p.

Instances

Functor (MinMaxQueue p)

Foldable (MinMaxQueue p)

(Eq p, Eq a) => Eq (MinMaxQueue p a)

(Ord p, Ord a) => Ord (MinMaxQueue p a)

Ord p => Monoid (MinMaxQueue p a)

empty :: MinMaxQueue p a

O(1) An empty priority queue.

null :: MinMaxQueue p a -> Bool

O(1) Test whether a priority queue is empty.

singleton :: Ord p => a -> p -> MinMaxQueue p a

O(1) A priority queue with a single entry.

insert :: Ord p => a -> p -> MinMaxQueue p a -> MinMaxQueue p a

O(log p) Insert a value with given priority into a priority queue.

deleteMin :: Ord p => MinMaxQueue p a -> MinMaxQueue p a

O(log p) Remove the value with the minimum priority from the queue.

If the queue is empty, deleteMin returns empty. Ties are broken arbitrarily.

deleteMax :: Ord p => MinMaxQueue p a -> MinMaxQueue p a

O(log p) Remove the value with the maximum priority from the queue.

If the queue is empty, deleteMax returns empty. Ties are broken arbitrarily.

minView :: Ord p => MinMaxQueue p a -> Maybe ((a, p), MinMaxQueue p a)

O(log p) View a priority queue to get the (value, priority) pair with the lowest priority and the remainder of the queue.

Ties are broken arbitrarily.

maxView :: Ord p => MinMaxQueue p a -> Maybe ((a, p), MinMaxQueue p a)

O(log p) View a priority queue to get the (value, priority) pair with the highest priority and the remainder of the queue.

Ties are broken arbitrarily.

minPriority :: Ord p => MinMaxQueue p a -> Maybe p

O(log p) Get the minimum priority of the elements in the queue.

maxPriority :: Ord p => MinMaxQueue p a -> Maybe p

O(log p) Get the maximum priority of the elements in the queue.

foldWithPriority :: Ord p => (p -> a -> b -> b) -> b -> MinMaxQueue p a -> b

O(n) Fold the priorities and values of a priority queue.

splitByPriority :: Ord p => p -> MinMaxQueue p a -> (MinMaxQueue p a, MinMaxQueue p a)

O(log p) Split a priority queue q into two queues (q1, q2) by the given priority p, such that q1 contains exactly the entries with priority less than p, and q2 containes exactly the entries with priority greater than or equal to p.

size :: Ord p => MinMaxQueue p a -> Int

O(n) The number of entries in a priority queue.

filter :: Ord p => (a -> Bool) -> MinMaxQueue p a -> MinMaxQueue p a

O(n log p) Filter all values that satisfy the predicate.

filterWithPriority :: Ord p => (a -> p -> Bool) -> MinMaxQueue p a -> MinMaxQueue p a

O(n log p) Filter all entries that satisfy the predicate.

toAscList :: Ord p => MinMaxQueue p a -> [(a, p)]

O(n) Convert the priority queue into a list of (value, priority) pairs in ascending priority.

Ties are broken in an arbitrary manner.