change directory names

22/lib/days/day2.ex

@@ -0,0 +1,68 @@
+defmodule AOC.Day2 do
+  use AOC.Day, day: 2
+
+  def parse_input(lines) do
+    Enum.map(lines, fn line ->
+      [move1, move2] =
+        line
+        |> String.split(" ")
+        |> Enum.map(fn c ->
+          c
+          |> String.to_charlist()
+          |> hd()
+        end)
+
+      {move1, move2}
+    end)
+  end
+
+  def part1(input) do
+    input
+    |> Enum.map(fn {move1, move2} ->
+      score =
+        case move2 do
+          ?X -> 1
+          ?Y -> 2
+          ?Z -> 3
+        end
+
+      score +
+        case {move1, move2} do
+          {?A, ?Y} -> 6
+          {?B, ?Z} -> 6
+          {?C, ?X} -> 6
+          {?A, ?X} -> 3
+          {?B, ?Y} -> 3
+          {?C, ?Z} -> 3
+          _ -> 0
+        end
+    end)
+    |> Enum.sum()
+  end
+
+  def part2(input) do
+    input
+    |> Enum.map(fn {move1, result} ->
+      score =
+        case result do
+          ?X -> 0
+          ?Y -> 3
+          ?Z -> 6
+        end
+
+      score +
+        case {move1, result} do
+          {?A, ?X} -> 3
+          {?A, ?Y} -> 1
+          {?A, ?Z} -> 2
+          {?B, ?X} -> 1
+          {?B, ?Y} -> 2
+          {?B, ?Z} -> 3
+          {?C, ?X} -> 2
+          {?C, ?Y} -> 3
+          {?C, ?Z} -> 1
+        end
+    end)
+    |> Enum.sum()
+  end
+end