upd

day_01/1.rb

@@ -13,7 +13,7 @@ class Main
       when "R"
         current = (current + magnitude) % 100
       when "L"
-        current = (current -= magnitude) % 100
+        current = (current - magnitude) % 100
       end
 
       if current == 0

day_01/2.rb

@@ -9,7 +9,7 @@ class Main
     $stdin.each_line do |line|
       direction, magnitude = line[0], line[1..].to_i
 
-      while magnitude > 0
+      magnitude.times do
         case direction
         when "R"
           current = (current + 1) % 100
@@ -20,8 +20,6 @@ class Main
         if current == 0
           count += 1
         end
-
-        magnitude -= 1
       end
     end