The previous version wasn't working correctly.

Author: sverm

BaseNegativeNumbers/BaseNegativeNumbers.rb

@@ -5,13 +5,13 @@
     else
         nums = n.chars.map.with_index do |c, i|
             j = n.length - i - 1
-            if j % 2 != 0
-                r ** (j + 1) - (r - c.to_i) * r ** j
+            if j % 2 != 0 && c.to_i != 0
+                r ** (j + 1) + (r - c.to_i) * r ** j
             else
                 c.to_i * r ** j
             end
         end
         nums.reduce(&:+).to_s r
     end
 
-puts result
+puts result