change directory names

21/lib/days/day1.ex

@@ -0,0 +1,17 @@
+defmodule AOC.Day1 do
+  def part1 do
+    AOC.Util.input_integers(1, 1)
+    |> Enum.chunk_every(2, 1, :discard)
+    |> Enum.map(fn [x, y] -> y > x end)
+    |> Enum.count(& &1)
+  end
+
+  def part2 do
+    AOC.Util.input_integers(1, 1)
+    |> Enum.chunk_every(3, 1, :discard)
+    |> Enum.map(&Enum.sum/1)
+    |> Enum.chunk_every(2, 1, :discard)
+    |> Enum.map(fn [x, y] -> y > x end)
+    |> Enum.count(& &1)
+  end
+end

21/lib/days/day2.ex

@@ -0,0 +1,27 @@
+defmodule AOC.Day2 do
+  def parse_input do
+    AOC.Util.input_lines(2, 1)
+    |> Enum.map(fn l ->
+      [dir, amount] = String.split(l, " ")
+      {String.to_atom(dir), String.to_integer(amount)}
+    end)
+  end
+
+  def part1 do
+    parse_input()
+    |> Enum.reduce({0, 0}, fn
+      {:forward, amount}, {distance, depth} -> {distance + amount, depth}
+      {:down, amount}, {distance, depth} -> {distance, depth + amount}
+      {:up, amount}, {distance, depth} -> {distance, depth - amount}
+    end)
+  end
+
+  def part2 do
+    parse_input()
+    |> Enum.reduce({0, 0, 0}, fn
+      {:down, amount}, {distance, depth, aim} -> {distance, depth, aim + amount}
+      {:up, amount}, {distance, depth, aim} -> {distance, depth, aim - amount}
+      {:forward, amount}, {distance, depth, aim} -> {distance + amount, depth + aim * amount, aim}
+    end)
+  end
+end

21/lib/util.ex

@@ -0,0 +1,21 @@
+defmodule AOC.Util do
+  def input_file_name(day, input) do
+    Path.join([File.cwd!(), "inputs", "day#{day}", "input#{input}.txt"])
+  end
+
+  def input_file(day, input) do
+    input_file_name(day, input)
+    |> File.read!()
+  end
+
+  def input_lines(day, input) do
+    input_file_name(day, input)
+    |> File.stream!()
+    |> Enum.map(&String.trim/1)
+  end
+
+  def input_integers(day, input) do
+    input_lines(day, input)
+    |> Enum.map(&String.to_integer/1)
+  end
+end