is_sorted

(* Write a function is_sorted : string array -> bool which checks if the values of the input array are sorted in strictly increasing order, implying that its elements are unique (use String.compare). *)

let is_sorted a : bool =
  let sorted = Array.fold_left (fun initial accumulator ->
      String.compare accumulator initial) a.(0) a in
  if sorted = 0
  then true
  else false
;;