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# ModuleBack_to_front

Traverse deque elements back-to-front. Incurs up to O(n) additional time and space cost over `Arbitrary_order`.

### Signature

val of_list : 'a list -> 'a t
include Container.S1 with type 'a t := 'a t
type 'a t
val mem : ?equal:('a -> 'a -> bool) -> 'a t -> 'a -> bool

Checks whether the provided element is there, using polymorphic compare if `equal` is not provided

val length : 'a t -> int
val is_empty : 'a t -> bool
val iter : 'a t -> f:('a -> unit) -> unit
val fold : 'a t -> init:'accum -> f:('accum -> 'a -> 'accum) -> 'accum

`fold t ~init ~f` returns `f (... f (f (f init e1) e2) e3 ...) en`, where `e1..en` are the elements of `t`

val exists : 'a t -> f:('a -> bool) -> bool

Returns `true` if and only if there exists an element for which the provided function evaluates to `true`. This is a short-circuiting operation.

val for_all : 'a t -> f:('a -> bool) -> bool

Returns `true` if and only if the provided function evaluates to `true` for all elements. This is a short-circuiting operation.

val count : 'a t -> f:('a -> bool) -> int

Returns the number of elements for which the provided function evaluates to true.

val sum : (module Commutative_group.S with type t = 'sum) -> 'a t -> f:('a -> 'sum) -> 'sum

Returns the sum of `f i` for i in the container

val find : 'a t -> f:('a -> bool) -> 'a option

Returns as an `option` the first element for which `f` evaluates to true.

val find_map : 'a t -> f:('a -> 'b option) -> 'b option

Returns the first evaluation of `f` that returns `Some`, and returns `None` if there is no such element.

val to_list : 'a t -> 'a list
val to_array : 'a t -> 'a array
val min_elt : 'a t -> cmp:('a -> 'a -> int) -> 'a option

Returns a minimum (resp maximum) element from the collection using the provided `cmp` function, or `None` if the collection is empty. In case of a tie, the first element encountered while traversing the collection is returned. The implementation uses `fold` so it has the same complexity as `fold`.

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