From b7e00339a35408ead3e5bb115674d854d6abcdaa Mon Sep 17 00:00:00 2001
From: Alpha Chen <alpha@kejadlen.dev>
Date: Sun, 12 Dec 2021 21:51:00 -0800
Subject: [PATCH] [2021][ruby][13.x] clean up getting the dir index

---
 2021/ruby/day_13.rb | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/2021/ruby/day_13.rb b/2021/ruby/day_13.rb
index d9f3f74..4d72242 100644
--- a/2021/ruby/day_13.rb
+++ b/2021/ruby/day_13.rb
@@ -3,12 +3,9 @@ dots, folds = ARGF.read.split("\n\n")
 dots = dots.scan(/(\d+),(\d+)/).map { _1.map(&:to_i) }
 folds = folds.scan(/(x|y)=(\d+)/).map { [_1, _2.to_i] }
 
+dirs = { ?x => 0, ?y => 1 }
 folds.each do |dir, axis|
-  index = case dir
-          when ?x then 0
-          when ?y then 1
-          else fail
-          end
+  index = dirs.fetch(dir)
   dots.select { _1[index] > axis }.each do |dot|
     dot[index] = axis - (dot[index] - axis)
   end