CS Fun B | Elaine Smith

graphs/possible_bipartition.py

@@ -8,5 +8,35 @@ def possible_bipartition(dislikes):
         Time Complexity: ?
         Space Complexity: ?
     """
-    pass
+
+    if not dislikes:
+        return True
+
+    # Each dog will be sorted in either Group 1 or Group 2
+    dog_groups = {dog:0 for dog in dislikes} # Dogs w/ value 0 are still unsorted
 
+    # Choose a starting dog & place in Group 1
+    first_dog = list(dislikes.keys())[0]
+    dog_groups[first_dog] = 1
+
+    # Initialize the queue; this is how we will keep track of neighbors
+    # Keep track of which dogs haven't been sorted yet so they can be added to queue if queue is empty
+    dogs_to_sort = [dog for dog in dislikes]
+    queue = [first_dog]
+
+    for dog in dog_groups:
+        while queue:
+            current_dog = queue.pop(0)
+            dogs_to_sort.remove(current_dog)
+
+            for dog in dislikes[current_dog]:
+                if dog_groups[dog] == 0:
+                    dog_groups[dog] = 2 if dog_groups[current_dog] == 1 else 1
+                    if dog in dogs_to_sort:
+                        queue.append(dog)
+                elif dog_groups[dog] == dog_groups[current_dog]:
+                    return False
+        if dogs_to_sort:
+            queue.append(dogs_to_sort[0])
+        else:
+            return True