# Module type Heap_intf.S

    module type S = sig .. end

    type 'a t

of_sexp and bin_io functions aren't supplied for heaps due to the difficulties in reconstructing the correct comparison function when de-serializing.

    include Container.S1

Mutation of the heap during iteration is not supported, but there is no check to prevent it. The behavior of a heap that is mutated during iteration is undefined.

    val min_elt : 'a t -> cmp:('a -> 'a -> int) -> 'a option

Even though these two functions are part of Container.S1, they are documented separately to make sure there is no confusion. They are independent of the comparison function used to order the heap. Instead, a traversal of the entire structure is done using the provided `cmp` function to find a min or max.

If you want to access the smallest element of the heap according to the heap's comparison function in constant time, you should use `top`.

    val max_elt : 'a t -> cmp:('a -> 'a -> int) -> 'a option

    val create : ?min_size:int -> cmp:('a -> 'a -> int) -> unit -> 'a t

`create ?min_size ~cmp` returns a new min-heap that can store `min_size` elements without reallocations, using ordering function `cmp`.

The top of the heap is the smallest element as determined by the provided comparison function. In particular, if `cmp x y < 0` then `x` will be "on top of" `y` in the heap.

Memory use is surprising in two ways:

1. The underlying pool never shrinks, so current memory use will at least be proportional to the largest number of elements that the heap has ever held.

2. Not all the memory is freed upon `remove`, but rather after some number of subsequent `pop` operations. Alternating `add` and `remove` operations can therefore use unbounded memory.

    val of_array : 'a array -> cmp:('a -> 'a -> int) -> 'a t

`min_size` (see `create`) will be set to the size of the input array or list.

    val of_list : 'a list -> cmp:('a -> 'a -> int) -> 'a t

    val top : 'a t -> 'a option

returns the top (i.e., smallest) element of the heap

    val top_exn : 'a t -> 'a

    val add : 'a t -> 'a -> unit

    val remove_top : 'a t -> unit

`remove_top t` does nothing if `t` is empty

    val pop : 'a t -> 'a option

This removes and returns the top (i.e. least) element

    val pop_exn : 'a t -> 'a

    val pop_if : 'a t -> ('a -> bool) -> 'a option

`pop_if t cond` returns `Some top_element` of `t` if it satisfies condition `cond`, removing it, or `None` in any other case.

    val copy : 'a t -> 'a t

`copy t` returns a shallow copy

    val sexp_of_t : ('a -> Sexplib.Sexp.t) -> 'a t -> Sexplib.Sexp.t

Mutation of the heap during iteration is not supported, but there is no check to prevent it. The behavior of a heap that is mutated during iteration is undefined.
Even though these two functions are part of Container.S1, they are documented separately to make sure there is no confusion. They are independent of the comparison function used to order the heap. Instead, a traversal of the entire structure is done using the provided `cmp` function to find a min or max.

If you want to access the smallest element of the heap according to the heap's comparison function in constant time, you should use `top`.
`create ?min_size ~cmp` returns a new min-heap that can store `min_size` elements without reallocations, using ordering function `cmp`.

The top of the heap is the smallest element as determined by the provided comparison function. In particular, if `cmp x y < 0` then `x` will be "on top of" `y` in the heap.

Memory use is surprising in two ways:

1. The underlying pool never shrinks, so current memory use will at least be proportional to the largest number of elements that the heap has ever held.

2. Not all the memory is freed upon `remove`, but rather after some number of subsequent `pop` operations. Alternating `add` and `remove` operations can therefore use unbounded memory.
`min_size` (see `create`) will be set to the size of the input array or list.
returns the top (i.e., smallest) element of the heap
`remove_top t` does nothing if `t` is empty
This removes and returns the top (i.e. least) element
`pop_if t cond` returns `Some top_element` of `t` if it satisfies condition `cond`, removing it, or `None` in any other case.
`copy t` returns a shallow copy