Add livebook

2022/elixir-livebook.livemd

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+<!-- livebook:{"persist_outputs":true} -->
+
+# Advent of Code 2022
+
+```elixir
+defmodule AoC do
+  def input_file_contents(n), do: File.read!(Path.expand("~/.cache/aoc2022/#{n}.input"))
+end
+
+import Enum
+```
+
+<!-- livebook:{"output":true} -->
+
+```
+Enum
+```
+
+## Day 1
+
+```elixir
+calories =
+  AoC.input_file_contents(1)
+  |> String.split("\n")
+  |> reduce([0], fn
+    "", l -> [0 | l]
+    s, [n | l] -> [n + String.to_integer(s) | l]
+  end)
+  |> sort()
+  |> reverse()
+
+IO.puts("Part 1: #{hd(calories)}")
+IO.puts("Part 2: #{Enum.take(calories, 3) |> Enum.sum()}")
+```
+
+<!-- livebook:{"output":true} -->
+
+```
+Part 1: 71924
+Part 2: 210406
+```
+
+<!-- livebook:{"output":true} -->
+
+```
+:ok
+```
+
+## Day 2
+
+```elixir
+m = %{
+  0 => %{0 => 4, 1 => 8, 2 => 3},
+  1 => %{0 => 1, 1 => 5, 2 => 9},
+  2 => %{0 => 7, 1 => 2, 2 => 6}
+}
+
+points = fn
+  <<a, _, b, 0x0A, rest::binary>>, {p1, p2}, r ->
+    {y, x} = {a - 65, b - 88}
+    r.(rest, {p1 + m[y][x], p2 + m[y][rem(3 + x + y - 1, 3)]}, r)
+
+  _, {p1, p2}, _ ->
+    {p1, p2}
+end
+
+{p1, p2} =
+  2
+  |> AoC.input_file_contents()
+  |> points.({0, 0}, points)
+
+IO.puts("Part 1: #{p1}")
+IO.puts("Part 2: #{p2}")
+```
+
+<!-- livebook:{"output":true} -->
+
+```
+Part 1: 12535
+Part 2: 15457
+```
+
+<!-- livebook:{"output":true} -->
+
+```
+:ok
+```