add naive solution day 9

9/naive_solution.ml

@@ -0,0 +1,81 @@
+open Stdio
+open Str
+
+
+let input =
+  let rec one_string inp= 
+    let line = In_channel.input_line In_channel.stdin in
+    match line with
+    | None -> inp
+    | Some x -> one_string (inp ^ x)
+  in one_string ""
+;;
+
+let repeat_string str n =
+  String.concat "" (List.init n (fun _ -> str))
+;;
+
+let expand dm =
+  let rec aux i acc=
+    if (i >= String.length dm) then
+      acc
+    else (if (i == String.length dm -1)
+         then
+           let id = string_of_int (i/2) in
+           let file_size = (int_of_char dm.[i] - int_of_char '0') in
+           let new_encoding = (repeat_string id file_size) in
+           (acc ^ new_encoding)
+         else
+           let id = string_of_int (i/2) in
+           let file_size = (int_of_char dm.[i] - int_of_char '0') in
+           let empty_space = (int_of_char dm.[i+1] - int_of_char '0') in
+           let new_encoding = (repeat_string id file_size) ^ (String.make empty_space '.') in
+           aux (i+2) (acc ^ new_encoding))
+  in
+  aux 0 String.empty
+;;
+
+let reverse_compact dm=
+  let rec aux left_most_pos accum =
+    try
+      if (left_most_pos < 0) then accum
+      else
+        (let nleft_most_pos = search_backward (regexp "[0-9]") dm left_most_pos in
+         aux (nleft_most_pos-1) (accum^(String.make 1 dm.[nleft_most_pos])))
+    with Not_found -> accum
+  in
+  aux (String.length dm) (String.empty)
+;;
+
+let compact dm rcomp=
+  let dm_len = (String.length rcomp) in
+  let rec aux i pos accum =
+    try
+      let npos = search_forward (regexp {|\.|}) dm pos in
+      aux (i+1) (npos+1) (accum ^ (String.sub dm pos (npos - pos)) ^ (String.make 1 rcomp.[i]))
+    with Not_found -> (String.sub accum 0 dm_len) ^ (String.make 1 '.')
+  in
+  aux 0 0 String.empty 
+;;
+
+let calculate_checksum dm=
+  let rec aux id accum =
+    if (dm.[id] == '.') then accum
+    else
+      let block = (int_of_char dm.[id] - int_of_char '0') in
+      (aux (id+1) ((id * block) + accum))
+  in
+  aux 0 0;;
+  
+let solve =
+  let expanded = expand input in
+  calculate_checksum
+    (compact expanded (reverse_compact expanded));
+;;
+
+let () =
+  printf "%s\n" (expand input);
+  (* printf "%s\n" (reverse_compact (expand input)); *)
+  (* printf "%s\n" (compact (expand input) (reverse_compact (expand input))); *)
+  (* printf "Total: %d\n" solve;; *)
+

9/solve_1.ml

@@ -1,40 +1,67 @@
 open Stdio
-open Str
+(* open Str *)
 
 
+let input =
+  let line = In_channel.input_line In_channel.stdin in
+  match line with
+  | None -> ""
+  | Some x -> x
+;;
+
 let expand dm =
   let rec aux i acc=
     if (i >= String.length dm) then
       acc
     else (if (i == String.length dm -1)
          then
-           let id = Char.chr (i/2 + int_of_char '0') in
+           let id = (i/2) in
            let file_size = (int_of_char dm.[i] - int_of_char '0') in
-           let new_encoding = (String.make file_size id) in
-           (acc ^ new_encoding)
+           let new_encoding = List.init file_size (fun _ -> id) in
+           new_encoding@acc
          else
-           let id = Char.chr (i/2 + int_of_char '0') in
+           let id = (i/2) in
            let file_size = (int_of_char dm.[i] - int_of_char '0') in
            let empty_space = (int_of_char dm.[i+1] - int_of_char '0') in
-           let new_encoding = (String.make file_size id) ^ (String.make empty_space '.') in
-           aux (i+2) (acc ^ new_encoding))
+           let new_encoding = (List.init empty_space (fun _ -> -1)) @ (List.init file_size (fun _ -> id)) in
+           aux (i+2) (new_encoding@acc))
   in
-  aux 0 String.empty
+  aux 0 []
+;;
+
+let reverse_list =
+  let rec aux acc = function
+    | [] -> acc
+    | x :: tl -> aux (x::acc) tl
+  in
+  aux []
+;;
+
+(* To be continued *)
+let compact dm =
+  let reversed = (reverse_list dm) in
+  reversed 
 ;;
 
 let calculate_checksum dm=
-  let rec aux id accum =
-    if (dm.[id] == '.') then accum
-    else
-      let block = (int_of_char dm.[id] - int_of_char '0') in
-      (aux (id+1) ((id * block) + accum))
+  let rec aux accum id = function
+    | [] -> accum
+    | x::tl -> (aux (id+1) ((id * x) + accum)) tl
   in
-  aux 0 0;;
+  aux 0 0 dm;;
   
-let solve = calculate_checksum "0099811188827773336446555566.............."
+let solve = 0
+  (* let expanded = expand input in *)
+  (* calculate_checksum *)
+    (* (compact expanded (reverse_compact expanded)); *)
 ;;
 
 let () =
-  printf "%s\n" (expand "2333133121414131402");
-  printf "Total: %d\n" solve;;
+  let dm = expand input in
+  List.iter (printf "%d") (dm);
+  printf "\n ----------------- \n";
+  List.iter (printf "%d") (reverse_list dm);
+  (* printf "%s\n" (reverse_compact (expand input)); *)
+  (* printf "%s\n" (compact (expand input) (reverse_compact (expand input))); *)
+  (* printf "Total: %d\n" solve;; *)