(* Zadanie 6 *)

let segments (list, x)=
  let rec helper(list, current, counter, acc)=
    if list = [] then reverse (current::acc)
    else if counter = 0 then helper(list, [], x, reverse current :: acc)
    else helper(List.tl list, List.hd list :: current, counter-1, acc)
           in helper(list, [], x, []);;

segments([1;2;3;4;5;6;7;8;9], 2);;
segments([1;2;3;4;5;6], 5);;
segments([],7);;
segments([6;3;5;6;44;3;6;67;8789;5;323;2;1;2;], 4);;

(* Zadanie 7 *)

let swap(list, x)=
  let rec helper(list, x, list1)=
    if list = [] && list1 = [] then []
    else if list = [] then list @ reverse list1
    else if x = 0 then list @ reverse list1
    else helper(List.tl list, x-1, List.hd list :: list1)
  in helper(list, x, []);;

swap(["a";"b";"5";"6"], 2);;
swap(["a";"b";"c";"d";"e";"f";"g";"h"], 5);;
swap(["a";"b";"c";"d";"e";"f";"g";"h"], 8);;
swap(["a";"b";"c";"d";"e";"f";"g";"h"], 7);;
swap([], 2);;