lib/text/white_similarity.rb in text-1.0.2 vs lib/text/white_similarity.rb in text-1.0.3

@@ -32,27 +32,30 @@
     def initialize
       @word_letter_pairs = {}
     end
 
     def similarity(str1, str2)
-      pairs1, length1 = word_letter_pairs(str1)
-      pairs2, length2 = word_letter_pairs(str2)
+      pairs1 = word_letter_pairs(str1)
+      pairs2 = word_letter_pairs(str2).dup
 
-      intersection = pairs1.inject(0) { |acc, pair|
-        pairs2.include?(pair) ? acc + 1 : acc
-      }
-      union = length1 + length2
+      union = pairs1.count + pairs2.count
 
+      intersection = 0
+      pairs1.each_with_index do |pair1|
+        if index = pairs2.index(pair1)
+          intersection += 1
+          pairs2.delete_at(index)
+        end
+      end
+
       (2.0 * intersection) / union
     end
 
   private
     def word_letter_pairs(str)
-      @word_letter_pairs[str] ||= (
-        pairs = str.upcase.split(/\s+/).map{ |word|
+      @word_letter_pairs[str] ||=
+        str.upcase.split(/\s+/).map{ |word|
           (0 ... (word.length - 1)).map { |i| word[i, 2] }
-        }.flatten
-        [Set.new(pairs), pairs.length]
-      )
+        }.flatten.freeze
     end
   end
 end