Improvements to day 7

lib/day7.ex

@@ -1,7 +1,46 @@
 defmodule Aoc2023.Day7 do
   use Aoc2023
 
-  @ranking_1 %{
+  def hand_type(values) do
+    values
+    |> Enum.frequencies()
+    |> then(fn freq ->
+      {jokers, freq_} = freq |> Map.pop(0, 0)
+      common = freq_ |> Enum.max_by(pipe(elem(1))) |> elem(0)
+      freq_ |> Map.update!(common, &(&1 + jokers))
+    end)
+    |> Enum.map(pipe(elem(1)))
+    |> Enum.sort(:desc)
+    |> case do
+      [5] -> 6
+      [4, 1] -> 5
+      [3, 2] -> 4
+      [3, 1, 1] -> 3
+      [2, 2, 1] -> 2
+      [2, 1, 1, 1] -> 1
+      [1, 1, 1, 1, 1] -> 0
+    end
+  end
+
+  def parse(input) do
+    fn rankings ->
+      input
+      |> lines
+      |> Enum.map(&String.split/1)
+      |> Enum.map(fn [hand, bid] ->
+        {
+          hand |> String.to_charlist() |> Enum.map(&Map.get(rankings, &1)),
+          bid |> String.to_integer()
+        }
+      end)
+      |> Enum.sort_by(elem(0) |> hand_type &&& elem(0), :asc)
+      |> Enum.with_index(1)
+      |> Enum.map(fn {{_, bid}, index} -> bid * index end)
+      |> Enum.sum()
+    end
+  end
+
+  @ranking %{
     ?A => 13,
     ?K => 12,
     ?Q => 11,
@@ -17,57 +56,11 @@ defmodule Aoc2023.Day7 do
     ?2 => 1
   }
 
-  @ranking_2 @ranking_1 |> Map.put(?J, 0)
-
-  def hand_type(values) do
-    for ty <- values, reduce: %{} do
-      m -> Map.update(m, ty, 1, &(&1 + 1))
-    end
-    |> Enum.map(pipe(elem(1)))
-    |> Enum.sort(:desc)
-    |> case do
-      [5] -> 6
-      [4, 1] -> 5
-      [3, 2] -> 4
-      [3, 1, 1] -> 3
-      [2, 2, 1] -> 2
-      [2, 1, 1, 1] -> 1
-      [1, 1, 1, 1, 1] -> 0
-    end
-  end
-
-  def parse(input) do
-    fn rankings, hand_rank ->
-      input
-      |> lines
-      |> Enum.map(&String.split/1)
-      |> Enum.map(fn [hand, bid] ->
-        {
-          hand |> String.to_charlist() |> Enum.map(&Map.get(rankings, &1)),
-          bid |> String.to_integer()
-        }
-      end)
-      |> Enum.sort_by(elem(0) |> hand_rank.() &&& elem(0), :asc)
-      |> Enum.with_index(1)
-      |> Enum.map(fn {{_, bid}, index} -> bid * index end)
-      |> Enum.sum()
-    end
-  end
-
   def part1(input) do
-    input.(@ranking_1, &hand_type/1)
+    input.(@ranking)
   end
 
   def part2(input) do
-    input.(
-      @ranking_2,
-      fn hand ->
-        @ranking_2
-        |> Enum.map(pipe(elem(1)))
-        |> Enum.map(fn j -> hand |> Enum.map(&if &1 == 0, do: j, else: &1) end)
-        |> Enum.map(&hand_type/1)
-        |> Enum.max()
-      end
-    )
+    input.(@ranking |> Map.put(?J, 0))
   end
 end