# Functor Pqueue.MakeMin

    module MakeMin: functor (E : OrderedType) -> Min  with type elt := E.t

Functor building an implementation of the min-priority queue structure given a totally ordered type for elements.

Parameters: |
`E` | : | `OrderedType`

## Min-priority queues

    type t

The type of priority queues.

    type elt

The type of priority queue elements.

    val create : unit -> t

Return a new priority queue, initially empty.

    val length : t -> int

Return the number of elements in a priority queue.

    val is_empty : t -> bool

`is_empty q` is `true` iff `q` is empty, that is, iff `length q = 0`.

    val add : t -> elt -> unit

`add q x` adds the element `x` in the priority queue `q`.

    val add_iter : t -> ((elt -> unit) -> 'x -> unit) -> 'x -> unit

`add_iter q iter x` adds each element of `x` to the end of `q`. This is `iter (add q) x`.

    val min_elt : t -> elt option

`min_elt q` is an element of `q` with minimal priority or `None` if the queue is empty. The queue is not modified.

    val get_min_elt : t -> elt

`get_min_elt q` returns an element of `q` with minimal priority, or raises `Invalid_argument` if the queue is empty. The queue is not modified.

    val pop_min : t -> elt option

`pop_min q` removes and returns an element in queue `q` with minimal priority, or returns `None` if the queue is empty.

    val remove_min : t -> unit

`remove_min q` removes an element in queue `q` with minimal priority. It does nothing if `q` is empty.

    val clear : t -> unit

`clear q` removes all elements from `q`.

    val copy : t -> t

`copy q` is a new priority queue with the same elements `q` has.

## Conversions from other data structures

    val of_array : elt array -> t

`of_array a` returns a new priority queue containing the elements of array `a`. Runs in linear time.

    val of_list : elt list -> t

`of_list l` returns a new priority queue containing the elements of list `l`. Runs in linear time.

    val of_iter : ((elt -> unit) -> 'x -> unit) -> 'x -> t

`of_iter iter x` returns a new priority queue containing the elements of `x`, obtained from `iter`.

For example, `of_iter Seq.iter s` returns a new priority queue containing all the elements of the sequence `s` (provided it is finite).

Runs in linear time (excluding the time spent in `iter`).

## Iteration

The order in which the elements of a priority queue are traversed is unspecified.

It is a programming error to mutate a priority queue (by adding or removing elements) during an iteration of the queue. Such an error may be detected and signaled by the backing dynamic array implementation, but this is not guaranteed.

    val iter_unordered : (elt -> unit) -> t -> unit

`iter_unordered f q` applies `f` to all elements in `q`. The order in which the elements are passed to `f` is unspecified.

The behavior is not specified if the priority queue is modified by `f` during the iteration.

    val fold_unordered : ('acc -> elt -> 'acc) -> 'acc -> t -> 'acc

`fold_unordered f accu q` is `(f (... (f (f accu x1) x2) ...)
xn)` where `x1,x2,...,xn` are the elements of `q`. The order in which the elements are passed to `f` is unspecified.

The behavior is not specified if the priority queue is modified by `f` during the iteration.