let min a =
  let index = 0 in
  let elt = a.(0) in
  let rec loop index elt =
    if index >= Array.length a then elt
    else if a.(index) < elt then let elt = a.(index) in elt
  in
  if Array.length a = 1 then a.(0)
  else let index = index + 1 in
    loop index  elt
;;