README.md

Min and max of a function

Recall the built-in option type:

type 'a option = Some of 'a | None

Write a function with the following type:

minmaxfun : (int -> 'a) -> int -> int -> ('a * 'a) option

such that minmaxfun f a b computes the minimum and the maximum of f in the range [a,b]. If the range is empty, then the function evaluates to None.

Your function must pass the following unit tests:

assert (minmaxfun (fun x -> x) (-2) 5 = Some (-2,5));;
assert (minmaxfun (fun x -> x) 5 (-2) = None);;
assert (minmaxfun (fun x -> x) 5 5 = Some (5,5));;
assert (minmaxfun (fun x -> x * x) (-2) 5 = Some (0,25));;

let curve x = x |> Float.of_int |> fun x -> x ** 3.0 -. 3.0 *. x;;
let arccos x = x |> Float.of_int |> Float.acos;;

assert (minmaxfun curve (-2) 2 = Some (-2.0,2.0));;
assert (minmaxfun arccos (-1) 1 = Some (0., Float.pi));;