2024 day 14 part 2

bin/day2414.ml

@@ -38,7 +38,23 @@ let loc_counts map p =
   let idx = get_quadrant p in
   IntMap.update idx update_count map
 
-let part robots =
+let print_locs lst =
+  let a = Array.make_matrix height width '.' in
+  let rec impl = function
+    | [] -> ()
+    | (x, y) :: t ->
+        if a.(y).(x) = '.' then a.(y).(x) <- '1'
+        else a.(y).(x) <- char_of_int (1 + int_of_char a.(y).(x));
+        impl t
+  in
+  impl lst;
+  Array.iter
+    (fun r ->
+      Array.iter print_char r;
+      print_newline ())
+    a
+
+let part1 robots =
   let counts =
     robots
     |> List.map normalize_velocity
@@ -48,4 +64,23 @@ let part robots =
   in
   IntMap.fold (fun _ v acc -> acc * v) counts 1
 
-let _ = Aoc.main robots_of_file [ (string_of_int, part) ]
+let find_tree max_n lst =
+  let num_robots = List.length lst in
+  let rec impl n =
+    if n > max_n then failwith "None found"
+    else
+      let poses = List.map (calc_pos_after n) lst in
+      if List.length (List.sort_uniq Aoc.IntPair.compare poses) = num_robots
+      then (
+        print_locs poses;
+        n)
+      else impl (n + 1)
+  in
+  impl 0
+
+let part2 robots =
+  let robots = List.map normalize_velocity robots in
+  find_tree 100000 robots
+
+let _ =
+  Aoc.main robots_of_file [ (string_of_int, part1); (string_of_int, part2) ]