(* b *)

let czyIstniejeFL f xs = List.fold_left (fun x y -> if f y then x || true else x || false) false xs;;

(* c *)

let czyIstniejeFR f xs = List.fold_right (fun x y -> if f x then true || y else false || y) xs false;;

(*Zadanie 4*)
let rec merge l x y = match (x,y) with
    | ([],_) -> y
    | (_,[]) -> x
    | (h1::t1, h2::t2) ->
    if l h1 h2
        then h1::(merge l t1 y)
        else h2::(merge l x t2);;

let rec split x y z = match x with
     | [] -> (y,z)
     | x::xs -> split xs z (x::y);;

let rec mergesort l x = match x with
    | ([] | _::[]) -> x
    | _ -> let (pri,seg) = split x [] []
           in merge l (mergesort l pri) (mergesort l seg);;

mergesort (>) [2;6;1;8];;