OCaml HackerRank template code

hackerrank.ml

(* Enter your code here. Read input from STDIN. Print output to STDOUT *)

let () = 
    let ary = ref [] in
    try ( while true do ary := (!ary@[read_int()]) done )
    with End_of_file ->
    begin
        List.fold_left (fun i x -> 
            if (i mod 2 != 0) then (print_int(x); print_string("\n"); (i + 1)) 
            else (i + 1)
        ) 0 (!ary); 
        ()
    end
;;

(* returns an array of n elements *)
let make_array n = Array.make n 1

let () =
  let len = read_int () in
  let arr = make_array len in
  Printf.printf "%d\n" (Array.length arr)
  
  
  (* Enter your code here. Read input from STDIN. Print output to STDOUT *)

let rec reverse xs = 
   match xs with
   | [] -> []
   | y::ys -> (reverse ys)@[y]
   
let () = 
    let ary = ref [] in
    try ( while true do ary := (!ary@[read_int()]) done )
    with End_of_file ->
    begin
        let reversed = reverse !ary in
        List.iter (fun x -> print_int(x); print_string("\n")) reversed
    end
;;

let () = 
    let ary = ref [] in
    try ( while true do ary := (!ary@[read_int()]) done )
    with End_of_file ->
    begin
        List.fold_left (fun i x -> 
            if (i mod 2 != 0) then (print_int(x); print_string("\n"); (i + 1)) 
            else (i + 1)
        ) 0 (!ary); 
        ()
    end
;;