Erica

lib/possible_bipartition.rb

@@ -1,4 +1,41 @@
+# I tried my best! All the test pass except for number 4. I know that the problem
+# is that I should be moving through the dislikes as they appear instead of just
+# linearly. However, for whatever when I tried using a stack and popping off the 
+# values, it didnt alter my stack--meaning the stack grew in length and I was 
+# trapped in a loop.  
 
 def possible_bipartition(dislikes)
-  raise NotImplementedError, "possible_bipartition isn't implemented yet"
-end
+  outer_length = dislikes.length
+  return true if outer_length <= 2
+
+  groupA = {}
+  groupB = {}
+
+  outer_length.times do |x|
+    if dislikes[x].length == 0
+      next
+    end
+
+    other = 'B'
+    if groupA[x] || groupB[x]
+      other = groupA[x] ? 'B' : 'A'
+    elsif !groupA[x] && !groupB[x] 
+      groupA[x] = 1
+    else
+      groupB[x] = 1
+      other = 'A'
+    end
+
+    dislikes[x].each do |i|
+      if other == 'B'
+        return false if groupA[i]
+        groupB[i] = 1
+      elsif other == 'A'
+        return false if groupB[i]
+        groupA[i] = 1
+      end
+    end
+  end
+
+  return true
+end