A priority queue with elements of type a. Supports extracting the minimum element.

\(O(1)\). The empty priority queue.

\(O(1)\). Is this the empty priority queue?

\(O(1)\). The number of elements in the queue.

\(O(1)\). Returns the minimum element. Throws an error on an empty queue.

\(O(1)\). Returns the minimum element of the queue, if the queue is nonempty.

\(O(\log n)\). Deletes the minimum element. If the queue is empty, does nothing.

\(O(\log n)\). Extracts the minimum element. Throws an error on an empty queue.

Retrieves the minimum element of the queue, and the queue stripped of that element, or Nothing if passed an empty queue.

\(O(1)\). Construct a priority queue with a single element.

Amortized \(O(1)\), worst-case \(O(\log n)\). Insert an element into the priority queue.

Amortized \(O(\log \min(n,m))\), worst-case \(O(\log \max(n,m))\). Take the union of two priority queues.

Takes the union of a list of priority queues. Equivalent to foldl' union empty.

\(O(k \log n)\)/. Index (subscript) operator, starting from 0. queue !! k returns the (k+1)th smallest element in the queue. Equivalent to toAscList queue !! k.

\(O(k \log n)\)/. take k, applied to a queue queue, returns a list of the smallest k elements of queue, or all elements of queue itself if k >= size queue.

\(O(k \log n)\)/. drop k, applied to a queue queue, returns queue with the smallest k elements deleted, or an empty queue if k >= size queue.

\(O(k \log n)\)/. Equivalent to (take k queue, drop k queue).

takeWhile, applied to a predicate p and a queue queue, returns the longest prefix (possibly empty) of queue of elements that satisfy p.

dropWhile p queue returns the queue remaining after takeWhile p queue.

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, 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.

\(O(n)\). Returns the queue with all elements not satisfying p removed.

\(O(n)\). Returns a pair where the first queue contains all elements satisfying p, and the second queue contains all elements not satisfying p.

\(O(n)\). Map elements and collect the Just results.

\(O(n)\). Map elements and separate the Left and Right results.

\(O(n)\). Creates a new priority queue containing the images of the elements of this queue. Equivalent to fromList . map f . toList.

\(O(n \log n)\). Performs a right fold on the elements of a priority queue in ascending order.

\(O(n \log n)\). Performs a left fold on the elements of a priority queue in ascending order.

\(O(n \log n)\). Performs a right fold on the elements of a priority queue in descending order. foldrDesc f z q == foldlAsc (flip f) z q.

\(O(n \log n)\). Performs a left fold on the elements of a priority queue in descending order. foldlDesc f z q == foldrAsc (flip f) z q.

\(O(n \log n)\). Returns the elements of the priority queue in ascending order. Equivalent to toAscList.

If the order of the elements is irrelevant, consider using toListU.

\(O(n \log n)\). Extracts the elements of the priority queue in ascending order.

\(O(n \log n)\). Extracts the elements of the priority queue in descending order.

\(O(n)\). Constructs a priority queue from an unordered list.

\(O(n)\). Constructs a priority queue from an ascending list. Warning: Does not check the precondition.

Performance note: Code using this function in a performance-sensitive context with an argument that is a "good producer" for list fusion should be compiled with -fspec-constr or -O2. For example, fromAscList . map f needs one of these options for best results.

\(O(n)\). Constructs a priority queue from an descending list. Warning: Does not check the precondition.

\(O(n)\). Unordered right fold on a priority queue.

\(O(n)\). Unordered left fold on a priority queue. This is rarely what you want; foldrU and foldlU' are more likely to perform well.

\(O(n)\). Unordered strict left fold on a priority queue.

Since: 1.4.2

\(O(n)\). Unordered monoidal fold on a priority queue.

Since: 1.4.2

Equivalent to toListU.

\(O(n)\). Returns the elements of the queue, in no particular order.

Constructs a priority queue out of the keys of the specified MinPQueue.

\(O(\log n)\). seqSpine q r forces the spine of q and returns r.

Note: The spine of a MinQueue is stored somewhat lazily. Most operations take great care to prevent chains of thunks from accumulating along the spine to the detriment of performance. However, mapU can leave expensive thunks in the structure and repeated applications of that function can create thunk chains.