thorn · June 19, 2012 14:32 · Jun 19, 2012
diff --git a/grouper.rb b/grouper.rb
@@ -0,0 +1,30 @@
+class Grouper
+
+  def self.group(list)
+    result = list.inject([]) do |res, gr1|
+      current_group = recursive_finder(list, gr1)
+      res << current_group
+    end
+    result | list
+  end
+
+  def self.recursive_finder(list, group)
+    current_group = group
+    list.each do |gr2|
+      if similar? current_group, gr2
+        list.delete group
+        list.delete gr2
+        current_group |= gr2 | recursive_finder(list, gr2)
+      end
+    end
+    current_group
+  end
+
+  def self.similar?(list1, list2)
+    for el in list1
+      return true if list2.include?(el)
+    end
+    false
+  end
+
+end
diff --git a/grouper_spec.rb b/grouper_spec.rb
@@ -0,0 +1,34 @@
+require_relative "../lib/grouper"
+describe Grouper do
+
+  before(:each) do
+    @list = [[1,2],[2,6],[3],[4,5],[5,1]]
+  end
+
+  it "should return true if two arrays have similar element" do
+    list1 = [1,2,3]
+    list2 = [3,4,5]
+    Grouper.similar?(list1, list2).should be true
+  end
+
+  it "should return false if there are no common element" do
+    list1 = [1,2,3]
+    list2 = [4,5,5]
+    Grouper.similar?(list1, list2).should be false
+  end
+
+  it "should return the list of groups" do
+    Grouper.group(@list).should == [[1,2,6,5,4],[3]]
+  end
+
+  it "should return identical array when there are no common elements" do
+    list2 = [[1,2],[3,4],[5,6]]
+    Grouper.group(list2).should == [[1,2],[5,6],[3,4]]
+  end
+
+  it "should return exact 1 array in array when all elements are common" do
+    list2 = [[1,2],[2,1]]
+    Grouper.group(list2).should == [[1,2]]
+  end
+
+end