From 1866e3aed5d3fb6db3ec879cb8e09cde6004571d Mon Sep 17 00:00:00 2001
From: sloane <git@sloanelybutsurely.com>
Date: Fri, 13 Dec 2024 21:04:01 -0500
Subject: [PATCH] solve 2024 day 13 pt. 1
---
2024/lib/2024/13.ex | 57 +++++++++++++++++++++++++++++++++++++++++++++
2024/mix.exs | 1 +
2024/mix.lock | 3 +++
3 files changed, 61 insertions(+)
create mode 100644 2024/lib/2024/13.ex
diff --git a/2024/lib/2024/13.ex b/2024/lib/2024/13.ex
new file mode 100644
index 0000000..fa4cfe1
--- /dev/null
+++ b/2024/lib/2024/13.ex
@@ -0,0 +1,57 @@
+import AOC
+
+aoc 2024, 13 do
+ def p1(input) do
+ input
+ |> read_machines()
+ |> Enum.map(&solve/1)
+ |> Enum.filter(&match?({:solution, a, b} when a <= 100 and b <= 100, &1))
+ |> Enum.map(&tokens_for_solution/1)
+ |> Enum.sum()
+ end
+
+ def p2(_input) do
+ end
+
+ defp solve(%{a: {xa, ya}, b: {xb, yb}, goal: {x, y}}) do
+ [a, b] =
+ [[xa, xb], [ya, yb]]
+ |> Nx.tensor()
+ |> Nx.LinAlg.solve(Nx.tensor([x, y]))
+ |> Nx.round()
+ |> Nx.to_list()
+ |> Enum.map(&trunc/1)
+
+ if xa * a + xb * b == x and ya * a + yb * b == y do
+ {:solution, a, b}
+ else
+ :impossible
+ end
+ end
+
+ defp tokens_for_solution({:solution, a, b}) do
+ 3 * a + b
+ end
+
+ # defp valid_solution?()
+
+ ## input
+
+ defp read_machines(str) do
+ ~r/Button A: X\+(\d+), Y\+(\d+)\nButton B: X\+(\d+), Y\+(\d+)\nPrize: X=(\d+), Y=(\d+)/m
+ |> Regex.scan(
+ str,
+ capture: :all_but_first
+ )
+ |> Enum.map(fn strings ->
+ [xa, ya, xb, yb, x, y] =
+ Enum.map(strings, &String.to_integer/1)
+
+ %{
+ a: {xa, ya},
+ b: {xb, yb},
+ goal: {x, y}
+ }
+ end)
+ end
+end
diff --git a/2024/mix.exs b/2024/mix.exs
index ddbeada..56649f9 100644
--- a/2024/mix.exs
+++ b/2024/mix.exs
@@ -23,6 +23,7 @@ defmodule Aoc2024.MixProject do
[
{:advent_of_code_utils, "~> 4.0"},
{:nimble_parsec, "~> 1.4"},
+ {:nx, "~> 0.9.2"},
{:styler, "~> 1.2", only: [:dev, :test], runtime: false}
]
end
diff --git a/2024/mix.lock b/2024/mix.lock
index 410e89f..0d0592c 100644
--- a/2024/mix.lock
+++ b/2024/mix.lock
@@ -1,7 +1,10 @@
%{
"advent_of_code_utils": {:hex, :advent_of_code_utils, "4.0.1", "591073a49600cbceae6d92e0fb2d2c56b59f6d383851e2a7c00c3bf0e4f33f4f", [:mix], [{:floki, "~> 0.34", [hex: :floki, repo: "hexpm", optional: false]}, {:tz, "~> 0.26", [hex: :tz, repo: "hexpm", optional: false]}], "hexpm", "684d016883d7b5443d9d22abc34013fb6f1d5d9ff114859a40890545a570eec8"},
+ "complex": {:hex, :complex, "0.5.0", "af2d2331ff6170b61bb738695e481b27a66780e18763e066ee2cd863d0b1dd92", [:mix], [], "hexpm", "2683bd3c184466cfb94fad74cbfddfaa94b860e27ad4ca1bffe3bff169d91ef1"},
"floki": {:hex, :floki, "0.36.3", "1102f93b16a55bc5383b85ae3ec470f82dee056eaeff9195e8afdf0ef2a43c30", [:mix], [], "hexpm", "fe0158bff509e407735f6d40b3ee0d7deb47f3f3ee7c6c182ad28599f9f6b27a"},
"nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
+ "nx": {:hex, :nx, "0.9.2", "17563029c01bf749aad3c31234326d7665abd0acc33ee2acbe531a4759f29a8a", [:mix], [{:complex, "~> 0.5", [hex: :complex, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "914d74741617d8103de8ab1f8c880353e555263e1c397b8a1109f79a3716557f"},
"styler": {:hex, :styler, "1.2.1", "28f9e3d4b065c22575c56b8ae03d05188add1b21bec5ae664fc1551e2dfcc41b", [:mix], [], "hexpm", "71dc33980e530d21ca54db9c2075e646faa6e7b744a9d4a3dfb0ff01f56595f0"},
+ "telemetry": {:hex, :telemetry, "1.3.0", "fedebbae410d715cf8e7062c96a1ef32ec22e764197f70cda73d82778d61e7a2", [:rebar3], [], "hexpm", "7015fc8919dbe63764f4b4b87a95b7c0996bd539e0d499be6ec9d7f3875b79e6"},
"tz": {:hex, :tz, "0.28.1", "717f5ffddfd1e475e2a233e221dc0b4b76c35c4b3650b060c8e3ba29dd6632e9", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:mint, "~> 1.6", [hex: :mint, repo: "hexpm", optional: true]}], "hexpm", "bfdca1aa1902643c6c43b77c1fb0cb3d744fd2f09a8a98405468afdee0848c8a"},
}