fix 04_recursive_max on ruby

04_quicksort/ruby/04_recursive_max.rb

@@ -1,10 +1,12 @@
 def max(list)
-  if list.empty?
+  return nil if list.empty?
-    nil
+
-  elsif list.length == 1
+  if list.length == 1
-    numbers[0]
+    list[0] # base case
   else
     sub_max = max(list[1..-1])
     list[0] > sub_max ? list[0] : sub_max
   end
 end
+
+puts max([2,3,8,5,5])