Day 3

lib/common.ex

@@ -12,4 +12,24 @@ defmodule Aoc2023.Common do
       fn (val) -> val |> unquote(expr) end
     end
   end
+
+  defmacro l &&& r do
+    quote do
+      fn val ->
+        l = val |> unquote(l)
+        r = val |> unquote(r)
+        {l, r}
+      end
+    end
+  end
+
+  def runs(lst, f) do
+    lst
+    |> Enum.with_index()
+    |> Enum.chunk_by(pipe(elem(0) |> f.()))
+    |> Enum.filter(pipe(Enum.at(0) |> elem(0) |> f.()))
+    |> Enum.map(Enum.at(0) |> elem(1) &&& length)
+  end
+
+  def id(x), do: x
 end