From ab7c6d5d333227f055476e1f7a15a2aca9b37c27 Mon Sep 17 00:00:00 2001
From: Adam Millerchip <adam@millerchip.net>
Date: Thu, 17 Dec 2020 12:07:00 +0900
Subject: [PATCH] reduce -> map_reduce

---
 day16/day16part2.exs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/day16/day16part2.exs b/day16/day16part2.exs
index 8c697b5..9a73c7d 100644
--- a/day16/day16part2.exs
+++ b/day16/day16part2.exs
@@ -44,9 +44,9 @@ defmodule Day16Part2 do
   def reduce_to_column_by_field_name(valid_fields_by_column) do
     valid_fields_by_column
     |> Enum.sort_by(fn {_k, v} -> length(v) end)
-    |> Enum.reduce({[], []}, fn {col, fields}, {identified, seen} ->
+    |> Enum.map_reduce([], fn {col, fields}, seen ->
       [field] = fields -- seen
-      {[{field, col} | identified], [field | seen]}
+      {{field, col}, [field | seen]}
     end)
     |> elem(0)
   end