2019 day 21 part 2 - an attempted solve

But it's not going to ever actually finish. The refactored version is much better
for part 1 though!

README.md

@@ -5,13 +5,13 @@
 My Elixir solutions for [Advent of Code](https://adventofcode.com/) (all years).
 
 <!-- stars start -->
-<p><img src="https://img.shields.io/static/v1?label=Total&message=442%20stars&style=for-the-badge&color=green" alt="442 stars" /></p>
+<p><img src="https://img.shields.io/static/v1?label=Total&message=441%20stars&style=for-the-badge&color=green" alt="441 stars" /></p>
 <p><a href="./lib/y2024/"><img src="https://img.shields.io/static/v1?label=2024&message=22%20stars&style=for-the-badge&color=orange" alt="22 stars" /></a><br />
 <a href="./lib/y2023/"><img src="https://img.shields.io/static/v1?label=2023&message=44%20stars&style=for-the-badge&color=green" alt="44 stars" /></a><br />
 <a href="./lib/y2022/"><img src="https://img.shields.io/static/v1?label=2022&message=%E2%AD%90%EF%B8%8F%2050%20stars%20%E2%AD%90%EF%B8%8F&style=for-the-badge&color=brightgreen" alt="50 stars" /></a><br />
 <a href="./lib/y2021/"><img src="https://img.shields.io/static/v1?label=2021&message=46%20stars&style=for-the-badge&color=green" alt="46 stars" /></a><br />
 <a href="./lib/y2020/"><img src="https://img.shields.io/static/v1?label=2020&message=39%20stars&style=for-the-badge&color=yellow" alt="39 stars" /></a><br />
-<a href="./lib/y2019/"><img src="https://img.shields.io/static/v1?label=2019&message=41%20stars&style=for-the-badge&color=green" alt="41 stars" /></a><br />
+<a href="./lib/y2019/"><img src="https://img.shields.io/static/v1?label=2019&message=40%20stars&style=for-the-badge&color=green" alt="40 stars" /></a><br />
 <a href="./lib/y2018/"><img src="https://img.shields.io/static/v1?label=2018&message=%E2%AD%90%EF%B8%8F%2050%20stars%20%E2%AD%90%EF%B8%8F&style=for-the-badge&color=brightgreen" alt="50 stars" /></a><br />
 <a href="./lib/y2017/"><img src="https://img.shields.io/static/v1?label=2017&message=%E2%AD%90%EF%B8%8F%2050%20stars%20%E2%AD%90%EF%B8%8F&style=for-the-badge&color=brightgreen" alt="50 stars" /></a><br />
 <a href="./lib/y2016/"><img src="https://img.shields.io/static/v1?label=2016&message=%E2%AD%90%EF%B8%8F%2050%20stars%20%E2%AD%90%EF%B8%8F&style=for-the-badge&color=brightgreen" alt="50 stars" /></a><br />

lib/y2019/README.md

@@ -2,7 +2,7 @@
 
 My Elixir solutions for [Advent of Code 2019](https://adventofcode.com/2019).
 
-<!-- stars 2019 start --><img src="https://img.shields.io/static/v1?label=2019&message=41%20stars&style=for-the-badge&color=green" alt="41 stars" /><!-- stars 2019 end -->
+<!-- stars 2019 start --><img src="https://img.shields.io/static/v1?label=2019&message=40%20stars&style=for-the-badge&color=green" alt="40 stars" /><!-- stars 2019 end -->
 
 ## Benchmarks
 
@@ -53,5 +53,5 @@ day 19, part 1         14.37       69.61 ms     ±1.76%       69.55 ms       72.
 day 19, part 2          4.21      237.63 ms     ±0.20%      237.70 ms      238.42 ms
 day 20, part 1         46.46       21.52 ms     ±5.19%       21.37 ms       24.56 ms
 day 20, part 2        0.0133       1.25 min     ±0.00%       1.25 min       1.25 min 🤭
-day 21, part 1          0.74         1.35 s    ±32.82%         1.36 s         1.75 s
+day 21, part 1          1.33      749.68 ms    ±29.82%      666.99 ms     1225.01 ms
 ```

lib/y2019/day21.ex

@@ -4,50 +4,91 @@ defmodule Y2019.Day21 do
 
   def part1(%Intcode{} = program) do
     program
-    |> Intcode.add_inputs(
-      ~c"#{find_formula(possible_var_combinations([:a, :b, :c, :d]))}\nWALK\n"
-    )
+    |> Intcode.add_inputs(~c"#{find_part_1_formula([:a, :b, :c, :d])}\nWALK\n")
     |> Intcode.run()
     |> Intcode.outputs()
     |> List.last()
   end
 
-  # @doc """
-  # iex> Day21.part2("update or delete me")
-  # "update or delete me"
-  # """
-  # def part2(input) do
-  #   input
+  # This doesn't actually ever finish
+  # def part2(program) do
+  #   result =
+  #     program
+  #     |> Intcode.add_inputs(
+  #       ~c"#{find_part_2_formula([:a, :b, :c, :d, :e, :f, :g, :h, :i])}\nRUN\n"
+  #     )
+  #     |> Intcode.run()
+  #     |> Intcode.outputs()
+
+  #   IO.puts(result)
+
+  #   List.last(result)
   # end
 
-  def find_formula(var_combinations) do
+  def find_part_1_formula(vars) do
     [
       {[],
        [
          # If we're in front of a gap we have to jump
-         {%{a: false, b: false, c: false, d: true, t: false, j: false}, true},
-         {%{a: false, b: false, c: true, d: true, t: false, j: false}, true},
-         {%{a: false, b: true, c: false, d: true, t: false, j: false}, true},
-         {%{a: false, b: true, c: true, d: true, t: false, j: false}, true},
+         {".###", true},
+         {"..##", true},
+         {".#.#", true},
+         {"...#", true},
 
          # Never jump when the fourth square is a hole because you'll fall in it
-         {%{a: true, b: true, c: true, d: false, t: false, j: false}, false},
-         {%{a: true, b: false, c: false, d: false, t: false, j: false}, false},
-         {%{a: true, b: true, c: false, d: false, t: false, j: false}, false},
-         {%{a: true, b: false, c: true, d: false, t: false, j: false}, false},
+         {"###.", false},
+         {"#...", false},
+         {"##..", false},
+         {"#.#.", false},
 
          # Nothing to worry about, keep walking forward
-         {%{a: true, b: true, c: true, d: true, t: false, j: false}, false},
+         {"####", false},
 
          # Jump just in case you can't after the gap
-         {%{a: true, b: false, c: false, d: true, t: false, j: false}, true},
-         {%{a: true, b: true, c: false, d: true, t: false, j: false}, true}
+         {"#..#", true},
+         {"##.#", true}
 
          # These ones I don't know about yet because either move could work
          # [true, false, true, 1] => ?,
-       ]}
+       ]
+       |> expand_combinations(vars)}
     ]
-    |> jump(var_combinations)
+    |> jump(possible_var_combinations(vars))
+  end
+
+  # def find_part_2_formula(vars) do
+  #   [
+  #     {
+  #       [],
+  #       [
+  #         {".########", true},
+  #         {"..#######", true},
+  #         {"...######", true},
+  #         {"#########", false},
+  #         {"##.######", true},
+  #         {"##...####", false},
+  #         {".#.##.#.#", true},
+  #         {"#.#.#####", false},
+  #         {"#.#.##.#.", false},
+  #         {"##.#.##.#", false},
+  #         {"#...#####", false},
+  #         {"##...####", false}
+  #       ]
+  #       |> expand_combinations(vars)
+  #     }
+  #   ]
+  #   |> jump(possible_var_combinations(vars))
+  # end
+
+  defp expand_combinations(list, vars) do
+    Enum.map(list, fn {road, result} ->
+      bools =
+        road
+        |> String.graphemes()
+        |> Enum.map(&(&1 == "#"))
+
+      {Enum.zip(vars, bools) |> Map.new() |> Map.merge(%{t: false, j: false}), result}
+    end)
   end
 
   def jump(possible_paths, var_combinations) do
@@ -64,7 +105,6 @@ defmodule Y2019.Day21 do
                op.([Map.fetch!(registers, one), Map.fetch!(registers, two)])
              ), result}
           end)
-          |> Enum.uniq_by(fn data -> data end)
         }
       end
       # If we're back where we started from, ditch this option
@@ -99,7 +139,7 @@ defmodule Y2019.Day21 do
   end
 
   def possible_var_combinations(range) do
-    [[:t, :j], [:j, :t] | Enum.flat_map(range, fn from -> [[from, :t], [from, :j]] end)]
+    [[:t, :j] | Enum.flat_map(range, fn from -> [[from, :t], [from, :j]] end)]
   end
 
   def parse_input(input) do

test/y2019/day21_test.exs

@@ -4,5 +4,5 @@ defmodule Y2019.Day21Test do
   doctest Day21
 
   test "verification, part 1", do: assert(Day21.part1_verify() == 19_349_939)
-  # test "verification, part 2", do: assert(Day21.part2_verify() == "update or delete me")
+  #  test "verification, part 2", do: assert(Day21.part2_verify() == "update or delete me")
 end