Day 6

lib/day6/day6.ex

@@ -41,25 +41,21 @@ defmodule Day6 do
     str
     |> String.replace(~r/\s/, "")
     |> String.to_charlist()
-    |> Enum.into(MapSet.new())
+    |> MapSet.new()
   end
 
   def questions_with_all_yes(str) do
-    str
-    |> String.split("\n")
-    |> Enum.map(fn person ->
-      person
-      |> String.to_charlist()
-      |> MapSet.new()
-    end)
-    |> Enum.reduce(nil, fn person, acc ->
-      case acc do
-        nil ->
-          person
+    people =
+      str
+      |> String.split("\n")
+      |> Enum.map(fn person ->
+        person
+        |> String.to_charlist()
+        |> MapSet.new()
+      end)
 
-        _ ->
-          MapSet.intersection(acc, person)
-      end
-    end)
+    people
+    |> Enum.drop(1)
+    |> Enum.reduce(List.first(people), &MapSet.intersection/2)
   end
 end