removed useless imports

6/main.ml

@@ -1,5 +1,4 @@
 open Printf;;
-open String;;
 
 let rec list_of_lines in_file =
   try
@@ -11,7 +10,7 @@ let rec list_of_lines in_file =
 
 let file_to_2d_array in_file =
   let lines = list_of_lines in_file in
-  let size_x = length @@ List.hd lines in
+  let size_x = String.length @@ List.hd lines in
   let size_y = List.length lines in
   let arr = Array.make_matrix size_x size_y '?' in
   List.iteri (fun j line -> String.iteri (fun i c -> arr.(j).(i) <- c) line) lines;