From 9d4492391c9d86fb28b2ca9a92a4c022062022d1 Mon Sep 17 00:00:00 2001
From: Sloane Perrault <sloane.perrault@gmail.com>
Date: Wed, 21 Sep 2022 09:19:53 -0400
Subject: [PATCH] solve day 5
---
2021/README.md | 3 ++-
2021/lib/2021/5.ex | 66 ++++++++++++++++++++++++++++++++++++++++++++++
2021/mix.exs | 1 +
2021/mix.lock | 1 +
4 files changed, 70 insertions(+), 1 deletion(-)
create mode 100644 2021/lib/2021/5.ex
diff --git a/2021/README.md b/2021/README.md
index 2a3d671..4d4b08f 100644
--- a/2021/README.md
+++ b/2021/README.md
@@ -15,7 +15,7 @@
| S | M | T | W | T | F | S |
| :-: | :-: | :-: | :-: | :-: | :-: | :-: |
| | | | [1] | [2] | [3] | [4] |
-| 5 | 6 | 7 | 8 | 9 | 10 | 11 |
+| [5] | 6 | 7 | 8 | 9 | 10 | 11 |
| 12 | 13 | 14 | 15 | 16 | 17 | 18 |
| 19 | 20 | 21 | 22 | 23 | 24 | 25 |
@@ -25,3 +25,4 @@
[2]: ./lib/2021/2.ex
[3]: ./lib/2021/3.ex
[4]: ./lib/2021/4.ex
+[5]: ./lib/2021/5.ex
diff --git a/2021/lib/2021/5.ex b/2021/lib/2021/5.ex
new file mode 100644
index 0000000..eb976c5
--- /dev/null
+++ b/2021/lib/2021/5.ex
@@ -0,0 +1,66 @@
+import AOC
+
+aoc 2021, 5 do
+ import NimbleParsec
+
+ defparsec(
+ :vent_readout_parsec,
+ integer(min: 1)
+ |> ignore(string(","))
+ |> integer(min: 1)
+ |> ignore(string(" -> "))
+ |> integer(min: 1)
+ |> ignore(string(","))
+ |> integer(min: 1)
+ )
+
+ def parse_vent_readout(line) do
+ {:ok, [x1, y1, x2, y2], _, _, _, _} = line |> vent_readout_parsec()
+
+ {{x1, y1}, {x2, y2}}
+ end
+
+ def input_stream(), do: super() |> Stream.map(&parse_vent_readout/1)
+
+ def p1 do
+ input_stream()
+ |> Enum.reduce(Map.new(), &record_line_on_map(&1, &2, false))
+ |> Map.values()
+ |> Enum.count(&(&1 > 1))
+ end
+
+ def p2 do
+ input_stream()
+ |> Enum.reduce(Map.new(), &record_line_on_map(&1, &2, true))
+ |> Map.values()
+ |> Enum.count(&(&1 > 1))
+ end
+
+ def record_line_on_map(line, map, include_diagonals),
+ do:
+ map
+ |> record_points_on_map(points_on_line(line, include_diagonals))
+
+ def record_points_on_map(map, points) do
+ for point <- points, reduce: map do
+ map -> Map.update(map, point, 1, &(&1 + 1))
+ end
+ end
+
+ # vertical lines
+ def points_on_line({{x, y1}, {x, y2}}, _) do
+ for y <- y1..y2, do: {x, y}
+ end
+
+ # horizontal lines
+ def points_on_line({{x1, y}, {x2, y}}, _) do
+ for x <- x1..x2, do: {x, y}
+ end
+
+ # diagonal lines
+ def points_on_line({{x1, y1}, {x2, y2}}, true) do
+ Enum.zip(x1..x2, y1..y2)
+ end
+
+ def points_on_line(_, false), do: []
+end
diff --git a/2021/mix.exs b/2021/mix.exs
index 25c1fd7..f481363 100644
--- a/2021/mix.exs
+++ b/2021/mix.exs
@@ -28,6 +28,7 @@ defmodule AdventOfCode.MixProject do
{:advent_of_code_utils, "~> 1.0"},
{:benchee, "~> 1.0", only: :dev},
{:exla, "~> 0.1.0-dev", github: "elixir-nx/nx", sparse: "exla"},
+ {:nimble_parsec, "~> 1.0"},
{:nx, "~> 0.1.0-dev", github: "elixir-nx/nx", sparse: "nx", override: true}
]
end
diff --git a/2021/mix.lock b/2021/mix.lock
index c21d716..d91fa9d 100644
--- a/2021/mix.lock
+++ b/2021/mix.lock
@@ -11,6 +11,7 @@
"mint": {:hex, :mint, "1.4.0", "cd7d2451b201fc8e4a8fd86257fb3878d9e3752899eb67b0c5b25b180bde1212", [:mix], [{:castore, "~> 0.1.0", [hex: :castore, repo: "hexpm", optional: true]}], "hexpm", "10a99e144b815cbf8522dccbc8199d15802440fc7a64d67b6853adb6fa170217"},
"mix_test_interactive": {:hex, :mix_test_interactive, "1.1.0", "e3e048ea8b56637c8e5614044483e11d78f81f70e9afb811c06ad3db69704c32", [:mix], [{:file_system, "~> 0.2", [hex: :file_system, repo: "hexpm", optional: false]}, {:typed_struct, "~> 0.2.1", [hex: :typed_struct, repo: "hexpm", optional: false]}], "hexpm", "2288a2edc735ca4879a7c17b9fd9fd4b8b84a57a775c3228db4655806a0a4799"},
"nimble_options": {:hex, :nimble_options, "0.3.7", "1e52dd7673d36138b1a5dede183b5d86dff175dc46d104a8e98e396b85b04670", [:mix], [], "hexpm", "2086907e6665c6b6579be54ef5001928df5231f355f71ed258f80a55e9f63633"},
+ "nimble_parsec": {:hex, :nimble_parsec, "1.2.0", "b44d75e2a6542dcb6acf5d71c32c74ca88960421b6874777f79153bbbbd7dccc", [:mix], [], "hexpm", "52b2871a7515a5ac49b00f214e4165a40724cf99798d8e4a65e4fd64ebd002c1"},
"nimble_pool": {:hex, :nimble_pool, "0.2.4", "1db8e9f8a53d967d595e0b32a17030cdb6c0dc4a451b8ac787bf601d3f7704c3", [:mix], [], "hexpm", "367e8071e137b787764e6a9992ccb57b276dc2282535f767a07d881951ebeac6"},
"nx": {:git, "https://github.com/elixir-nx/nx.git", "e23a678bf0ebcbbafe03f1b5ed78623f052ad486", [sparse: "nx"]},
"progress_bar": {:hex, :progress_bar, "2.0.1", "7b40200112ae533d5adceb80ff75fbe66dc753bca5f6c55c073bfc122d71896d", [:mix], [{:decimal, "~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}], "hexpm", "2519eb58a2f149a3a094e729378256d8cb6d96a259ec94841bd69fdc71f18f87"},