class AnimalQueue(object):
def __init__(self):
self.dogs = Queue()
self.cats = Queue()
self.order = 0
def enqueue(self, animal):
animal.order = self.order
self.order += 1
if isinstance(animal, Dog):
self.dogs.enqueue(animal)
if isinstance(animal, Cat):
self.cats.enqueue(animal)
def dequeue_any(self):
if self.dogs.queue_empty():
return self.dequeue_cat()
elif self.cats.queue_empty():
return self.dequeue_dog()
elif self.dogs.peek().order < self.cats.peek().order:
return self.dequeue_dog()
else:
return self.dequeue_cat()
def dequeue_dog(self):
return self.dogs.dequeue()
def dequeue_cat(self):
return self.cats.dequeue()
def subtree(r1, r2):
q = Queue()
q.enqueue(r1)
while not q.queue_empty():
x = q.dequeue()
if x.key == r2.key and same_tree(x, r2):
return True
if x.left is not None:
q.enqueue(x.left)
if x.right is not None:
q.enqueue(x.right)
return False
def same_tree2(root1, root2):
q = Queue()
q.enqueue(root1)
q.enqueue(root2)
while not q.queue_empty():
x, y = q.dequeue(), q.dequeue()
if x.key != y.key:
return False
if x.left is not None and y.left is not None:
q.enqueue(x.left)
q.enqueue(y.left)
elif x.left is not y.left:
return False
if x.right is not None and y.right is not None:
q.enqueue(x.right)
q.enqueue(y.right)
elif x.right is not y.right:
return False
return True
def exists_route_bfs(directed_graph, u, v):
"""Returns True if there exist a route between nodes u and v
in directed_graph. Uses BFS.
"""
if u is v:
return True
for w in directed_graph:
w.discovered = False
q = Queue()
q.enqueue(u)
u.discovered = True
while not q.queue_empty():
u = q.dequeue()
for neighbour in u.neighbours:
if not neighbour.discovered:
if neighbour is v:
return True
q.enqueue(neighbour)
neighbour.discovered = True
return False
