Data update

Task/Find-common-directory-path/OCaml/find-common-directory-path.ocaml

@@ -1,27 +1,20 @@
-let rec aux acc paths =
-  if List.mem [] paths
-  then (List.rev acc) else
-  let heads = List.map List.hd paths in
-  let item = List.hd heads in
-  let all_the_same =
-    List.for_all ((=) item) (List.tl heads)
-  in
-  if all_the_same
-  then aux (item::acc) (List.map List.tl paths)
-  else (List.rev acc)
+let rec common_prefix xs ys = match xs, ys with
+  | x :: xs, y :: ys when x = y -> x :: common_prefix xs ys
+  | _ -> []
 
-let common_prefix sep = function
-  | [] -> invalid_arg "common_prefix"
-  | dirs ->
-      let paths = List.map (Str.split (Str.regexp_string sep)) dirs in
-      let res = aux [] paths in
-      (sep ^ (String.concat sep res))
+let common_prefix_all = function
+  | x :: xs -> List.fold_left common_prefix x xs
+  | _ -> []
 
-let () =
-  let dirs = [
+let common_ancestor ~sep paths =
+  List.map Str.(split_delim (regexp_string sep)) paths
+  |> common_prefix_all
+  |> String.concat sep
+
+let _ = assert begin
+  common_ancestor ~sep:"/" [
     "/home/user1/tmp/coverage/test";
     "/home/user1/tmp/covert/operator";
     "/home/user1/tmp/coven/members";
-  ] in
-  print_endline (common_prefix "/" dirs);
-;;
+  ] = "/home/user1/tmp"
+end