Formatted

lib/year_2025/day1.exs

@@ -1,8 +1,9 @@
-filepath = Path.join([File.cwd!, "lib", "year_2025", "day1_input.txt"])
+filepath = Path.join([File.cwd!(), "lib", "year_2025", "day1_input.txt"])
-ops = File.stream!(filepath)
+
-|>Stream.map(&String.trim_trailing/1)
+ops =
-|>Enum.to_list
+  File.stream!(filepath)
+  |> Stream.map(&String.trim_trailing/1)
+  |> Enum.to_list()
 
 {_, zeroes} = AdventOfCode.Year2025.Dial.rotate(ops)
 IO.puts(zeroes)
-

lib/year_2025/dial.ex

@@ -3,17 +3,18 @@ defmodule AdventOfCode.Year2025.Dial do
   def rotate(operations), do: rotate(50, operations, 0)
 
   # When no operations remain, return the number of zeroes
-  def rotate(index, [], zeroes), do: { index, zeroes }
+  def rotate(index, [], zeroes), do: {index, zeroes}
 
   # Compute the new dial position
   def rotate(index, [head | tail], zeroes) do
-    { new_index, _crosses } = case head do
+    {new_index, _crosses} =
-      "R" <> number -> rotate_right(index, String.to_integer(number))
+      case head do
-      "L" <> number -> rotate_left(index, String.to_integer(number))
+        "R" <> number -> rotate_right(index, String.to_integer(number))
-    end
+        "L" <> number -> rotate_left(index, String.to_integer(number))
+      end
 
     case new_index do
-      0 -> rotate(new_index, tail, zeroes+1)
+      0 -> rotate(new_index, tail, zeroes + 1)
       _ -> rotate(new_index, tail, zeroes)
     end
   end
@@ -21,18 +22,20 @@ defmodule AdventOfCode.Year2025.Dial do
   defp rotate_right(index, number) do
     crosses = div(number, 100)
     diff = index + rem(number, 100)
+
     case diff do
-      diff when diff <= 99 -> { diff, crosses }
+      diff when diff <= 99 -> {diff, crosses}
-      diff when diff > 99 -> { diff - 100, crosses + 1 }
+      diff when diff > 99 -> {diff - 100, crosses + 1}
     end
   end
 
   defp rotate_left(index, number) do
     crosses = div(number, 100)
     diff = index - rem(number, 100)
+
     case diff do
-      diff when diff >= 0 -> { diff, crosses }
+      diff when diff >= 0 -> {diff, crosses}
-      diff when diff < 0 -> { diff + 100, crosses + 1 }
+      diff when diff < 0 -> {diff + 100, crosses + 1}
     end
   end
 end

test/year_2025/dial_test.exs

@@ -4,7 +4,7 @@ defmodule AdventOfCode.Year2025.DialTest do
   import AdventOfCode.Year2025.Dial
 
   test "dial starts at 50" do
-    { index, _ } = rotate([])
+    {index, _} = rotate([])
     assert index == 50
   end
 
@@ -15,7 +15,7 @@ defmodule AdventOfCode.Year2025.DialTest do
 
   test "rotate left decrements index" do
     {index, _} = rotate(["L1"])
-    assert index ==49 
+    assert index == 49
   end
 
   test "increments zero crossings when landing on zero" do