finally solved day 16 part 2 (in 100 seconds :P)
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ryan
parent
8db68c9baf
commit
1df5532c24
117
src/day16.ml
117
src/day16.ml
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@ -22,12 +22,6 @@ type room =
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}
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[@@deriving show { with_path = false }]
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type valve =
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{ flow : int
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; valves : (string * int) list
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}
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[@@deriving show { with_path = false }]
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let parse_valves lines =
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let rooms = Hashtbl.create 100 in
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lines
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@ -40,10 +34,10 @@ let parse_valves lines =
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let valves =
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Hashtbl.to_list rooms
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|> List.filter_map (fun (_, { name; flow; tunnels = _ }) ->
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if flow > 0 || String.(name = "AA") then Some (name, flow) else None)
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if flow > 0 then Some (name, flow) else None)
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in
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let distances = Hashtbl.create 100 in
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valves
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valves @ [ "AA", 0 ]
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|> List.iter (fun (from, _) ->
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let dist_of =
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Fun.(
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@ -62,66 +56,57 @@ let parse_valves lines =
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valves, get_dist
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;;
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(* let get_valve valves name = Option.get_exn_or "poo" @@ Hashtbl.get valves name *)
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(* (\* I think this algorithm fails for 15.1 example and 15.2 because it can't do *)
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(* backtracking. But if I dont filter out visited nodes, it takes forever to *)
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(* run. prob need to find the shortest path between each valve thats worth *)
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(* opening before doing the traversal. *\) *)
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(* let traverse valves = *)
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(* Utils.memo (fun self released current time opened visited -> *)
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(* if time = 0 *)
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(* then released, opened *)
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(* else ( *)
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(* let open_current = *)
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(* if current.flow > 0 && (not @@ List.mem current.name opened) *)
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(* then ( *)
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(* let time' = time - 1 in *)
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(* let released' = released + (current.flow * time') in *)
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(* [ self released' current time' (current.name :: opened) visited ]) *)
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(* else [] *)
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(* in *)
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(* let follow_a_tunnel = *)
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(* current.tunnels *)
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(* |> List.filter (fun tunnel -> not @@ List.mem tunnel visited) *)
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(* |> List.map (fun name -> *)
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(* let current' = get_valve valves name in *)
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(* let time' = time - 1 in *)
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(* self released current' time' opened (current.name :: visited)) *)
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(* in *)
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(* Option.get_or ~default:(released, opened) *)
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(* @@ List.reduce *)
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(* (fun ((a, _) as a') ((b, _) as b') -> if a > b then a' else b') *)
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(* (open_current @ follow_a_tunnel))) *)
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(* ;; *)
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(* let solve_part_1 lines = *)
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(* let valves, distances = parse_valves lines in *)
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(* let start = get_valve valves "AA" in *)
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(* let released, _ = traverse valves 0 start 30 [] [] in *)
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(* released *)
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(* ;; *)
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(* let%expect_test "Day 16.1 example" = *)
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(* Printf.printf "%i" @@ solve_part_1 @@ example_lines; *)
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(* [%expect {| 1358 |}] *)
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(* ;; *)
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let%expect_test "Day 16.1" =
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let _, get_dist = parse_valves example_lines in
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Printf.printf "%i" @@ get_dist "AA" "HH";
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[%expect {| 5 |}]
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let traverse get_dist =
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let rec traverse' valves time elephant current =
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let options =
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valves
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|> List.filter_map (fun (name, flow) ->
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let dist = get_dist current name in
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let delta = dist + 1 in
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let score = flow * (time - delta) in
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if score < 0
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then None
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else (
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let valves' = List.remove_assoc ~eq:String.equal name valves in
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Some (score + traverse' valves' (time - delta) elephant name)))
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in
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(options @ if elephant then [ traverse' valves 26 false "AA" ] else [ 0 ])
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|> List.reduce Int.max
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|> Option.get_or ~default:0
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in
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traverse'
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;;
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(* let solve_part_2 lines = *)
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(* let valves = parse_valves lines in *)
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(* let start = get_valve valves "AA" in *)
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(* let released, opened = traverse valves 0 start 26 [] [] in *)
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(* let released', _ = traverse valves released start 26 opened [] in *)
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(* released' *)
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(* ;; *)
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let%expect_test "example" =
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let valves, get_dist = parse_valves example_lines in
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Printf.printf "part 1: %i\n" @@ traverse get_dist valves 30 false "AA";
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Printf.printf "part 2: %i\n" @@ traverse get_dist valves 26 true "AA";
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[%expect {|
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part 1: 1651
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part 2: 1707 |}]
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;;
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let%expect_test "Day 16.1 example" =
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let valves, get_dist = parse_valves example_lines in
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Printf.printf "%i\n" @@ traverse get_dist valves 30 false "AA";
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[%expect {| 1651 |}]
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;;
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let%expect_test "Day 16.2 example" =
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let valves, get_dist = parse_valves example_lines in
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Printf.printf "%i\n" @@ traverse get_dist valves 26 true "AA";
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[%expect {| 1707 |}]
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;;
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let%expect_test "Day 16.1" =
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let valves, get_dist = parse_valves @@ Utils.lines_of_input 16 in
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Printf.printf "%i\n" @@ traverse get_dist valves 30 false "AA";
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[%expect {| 2265 |}]
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;;
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(* took 106.465 sec >:( *)
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(* let%expect_test "Day 16.2" = *)
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(* Printf.printf "%i" @@ solve_part_2 @@ Utils.lines_of_input 16; *)
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(* [%expect {| 2353 |}] *)
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(* let valves, get_dist = parse_valves @@ Utils.lines_of_input 16 in *)
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(* Printf.printf "%i\n" @@ traverse get_dist valves 26 true "AA"; *)
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(* [%expect {| 2811 |}] *)
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(* ;; *)
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@ -22,7 +22,7 @@ let lines_of_input day =
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]} *)
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let memo f =
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let open Hashtbl in
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let cache = create 1000 in
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let cache = create 100000 in
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let rec f_mem k =
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try find cache k with
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| Not_found ->
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