removed useless imports

7/main.ml

@@ -1,5 +1,4 @@
 open Printf;;
-open String;;
 
 let rec list_of_lines in_file =
   try
@@ -13,7 +12,7 @@ let clean_string str =
   str |> String.split_on_char ':' |> List.hd
 
 let rec parse_int_list sep str =
-  let list1 = (List.filter (fun a -> length a != 0) (String.split_on_char sep str)) in
+  let list1 = (List.filter (fun a -> String.length a != 0) (String.split_on_char sep str)) in
   List.map (fun x -> int_of_string @@ clean_string x) list1
 
 let rec is_possible_inner goal operand_list =