def test_multiple_dequeue():
q = Queue()
q.enqueue('first value')
q.enqueue('second value')
q.dequeue()
q.dequeue()
assert q.front == None
class AnimalShelter():
def __init__(self):
self.cat_queue = Queue()
self.dog_queue = Queue()
self.animals_served = 0
def enqueue(self, incoming_animal):
type_of_animal = type(incoming_animal)
# https://docs.python.org/3/library/functions.html#type
self.animals_served += 1
incoming_animal.animal_id = self.animals_served
if type_of_animal == Cat:
self.cat_queue.enqueue(incoming_animal)
elif type_of_animal == Dog:
self.dog_queue.enqueue(incoming_animal)
else:
raise InvalidOperationError("Sorry, we don't accept that type of animal here.")
def dequeue(self, request_type = None):
if request_type == "cat":
return self.cat_queue.dequeue()
elif request_type == "dog":
return self.dog_queue.dequeue()
elif request_type == None:
#which queue is older?
next_cat = self.cat_queue.peek().animal_id
next_dog = self.dog_queue.peek().animal_id
if next_cat < next_dog:
return self.cat_queue.dequeue()
else:
return self.dog_queue.dequeue()
else:
return None
def test_peek_post_dequeue():
q = Queue()
q.enqueue("apples")
q.enqueue("bananas")
q.dequeue()
actual = q.peek()
expected = "bananas"
assert actual == expected
def test_dequeue():
letters = Queue()
letters.enqueue('A')
letters.enqueue('B')
letters.enqueue('C')
assert letters.dequeue() == 'A'
assert letters.dequeue() == 'B'
assert letters.dequeue() == 'C'
assert letters.dequeue() is None
def test_stacks_and_queues_10 ():
queue = Queue()
queue.enquene('a')
queue.enquene('b')
queue.enquene('c')
queue.dequeue()
actual = queue.front.value
expected = 'b'
assert actual == expected
def test_exhausted():
q = Queue()
q.enqueue("apple")
q.enqueue("banana")
q.enqueue("cucumber")
q.dequeue()
q.dequeue()
q.dequeue()
actual = q.is_empty()
expected = True
assert actual == expected
def test_dequeue_until_empty():
q = Queue()
q.enqueue("apple")
q.enqueue("banana")
q.enqueue("cucumber")
q.dequeue()
q.dequeue()
q.dequeue()
actual = q.q_is_empty()
expected = True
assert actual == expected
def test_stacks_and_queues_12 ():
queue = Queue()
queue.enquene('a')
queue.enquene('b')
queue.enquene('c')
queue.dequeue()
queue.dequeue()
queue.dequeue()
actual = queue.peek()
expected = None
assert actual == expected
def test_dequeue_multiple():
q4 = Queue()
q4.enqueue(7)
q4.enqueue(5)
q4.enqueue(3)
q4.enqueue(1)
q4.dequeue()
q4.dequeue()
q4.dequeue()
q4.dequeue()
assert q4.front == None
assert q4.rear == None
assert q4.is_empty()
def test_can_successfully_empty_a_queue_after_multiple_dequeues():
new_queue = Queue()
new_queue.enqueue('One')
new_queue.enqueue('Two')
new_queue.enqueue('Three')
new_queue.enqueue('Four')
new_queue.dequeue()
new_queue.dequeue()
new_queue.dequeue()
new_queue.dequeue()
expected = True
actual = new_queue.isempty()
assert expected == actual
def breadth_first(self, starting_node, action_function=None):
list_of_nodes = []
breadth_queue = Queue()
breadth_queue.enqueue(starting_node)
starting_node.visited = True
i = 1
while not breadth_queue.is_empty():
print(f"trip {i} through while loop")
i += 1
current_vertex = breadth_queue.dequeue()
list_of_nodes.append(current_vertex)
current_edges = self._adjacency_list[current_vertex]
for edge in current_edges:
if edge.vertex.visited == False:
breadth_queue.enqueue(edge.vertex)
edge.vertex.visited = True
# NOTE: Doing this traversal method over the weekend, I choose to give each Vertex an attribute of visited that had a value of True or False. During class on Monday, JB did say that some are set up this way. However, he said he prefers to keep track of the visited nodes by using a variable of type set. This prevents any possibility of leaving an item visited attribute as true. The set variable would be cleared to length 0 at the start of each breadth traversal.
for node in self._adjacency_list:
node.visted = False
list_of_values_of_nodes = list(map(lambda x: x.value, list_of_nodes))
# attempts to get the passed in function to act on the list_of_nodes and thereby append to the list existing in the space from where this method was called is on the next line.
# map(action_function(list_of_nodes))
# return list_of_nodes
return list_of_values_of_nodes
def test_dequeue_when_full():
q = Queue()
q.enqueue("apples")
q.enqueue("bananas")
actual = q.dequeue()
expected = "apples"
assert actual == expected
def test_dequeue():
q = Queue()
q.enqueue("apple")
q.enqueue("banana")
actual = q.dequeue()
expected = "apple"
assert actual == expected
def test_dequeue():
q2 = Queue()
q2.enqueue(7)
q2.enqueue(5)
q2.enqueue(3)
q2.enqueue(1)
assert q2.rear.value == 1
assert q2.dequeue() == 7
assert q2.front.value == 5
def traverse_breadth_first(self):
q = Queue()
q.enqueue(self.root)
while q.peek():
curr = q.dequeue()
yield curr.value
if curr.l_child:
q.enqueue(curr.l_child)
if curr.r_child:
q.enqueue(curr.r_child)
def traverse_breath_first(self):
queue = Queue()
curr = self.root
queue.enqueue(curr)
# import pdb; pdb.set_trace()
while queue.is_empty():
curr = queue.dequeue()
if curr.child_left:
queue.enqueue(curr.child_left)
if curr.child_right:
queue.enqueue(curr.child_right)
yield (curr.value)
def breath_first(self):
rtn = []
queue = Queue()
curr = self.root
queue.enqueue(curr)
# import pdb; pdb.set_trace()
while queue.is_empty():
curr = queue.dequeue()
if curr.child_left:
queue.enqueue(curr.child_left)
if curr.child_right:
queue.enqueue(curr.child_right)
rtn.append(curr.value)
return rtn
def breadth_traverse(self):
""" Breadth-first traversal of binary tree """
output = []
q = Queue()
q.enqueue(self.root)
while q.peek():
curr = q.dequeue()
output.append(curr.value)
if curr.l_child:
q.enqueue(curr.l_child)
if curr.r_child:
q.enqueue(curr.r_child)
return output
def breadth_first(self) -> list:
""" takes a Binary Tree as its unique input, traverse the input tree using a Breadth-first approach, and return a list of the values in the tree in the order they were encountered. """
frontier = Queue()
frontier.enqueue(self.root)
explored = []
current = None
while not frontier.is_empty():
current = frontier.dequeue()
explored.append(current.value)
if current.left:
frontier.enqueue(current.left)
if current.right:
frontier.enqueue(current.right)
return explored
def find_max_value(self):
max_value = self.root.value
curr=self.root
queue=Queue()
queue.enqueue(curr)
# import pdb; pdb.set_trace()
while queue.is_empty():
curr = queue.dequeue()
if curr.value > max_value:
max_value=curr.value
if curr.child_left:
queue.enqueue(curr.child_left)
if curr.child_right:
queue.enqueue(curr.child_right)
return max_value
def breadth_first_traverse(self, start_vert):
""" Returns a list of graph vertex values in breadth-first order
:param start_vert: Vertex object
:returns: list of vertex values
"""
q = Queue()
output = []
q.enqueue(start_vert)
start_vert.visited = True
while q.peek():
vert = q.dequeue()
output.append(vert.value)
for v, w in vert.adjacencies:
if not v.visited:
q.enqueue(v)
v.visited = True
self._reset_visited()
return output
def traverse(self, node, debug=False):
queue = Queue()
ret_baby = []
if not node:
return 'babies'
visited = {}
queue.enqueue(node)
while queue.peek():
current = queue.dequeue()
visited[current] = True
if current == 'this queue is empty buddy':
break
for baby_node in self._adjacency_list[current]:
if baby_node == None:
break
if not baby_node in visited:
queue.enqueue(baby_node)
ret_baby.append(current.value)
if debug:
breakpoint()
return ret_baby
def breadthOrder(self):
'''
This method prints out the tree using a breadth-first approach that steps across the width of the tree before descending another level.
'''
ordered_list = []
tree_node_queue = Queue()
tree_node_queue.enqueue(self.root)
while not tree_node_queue.is_empty():
tree_node_removed_from_queue = tree_node_queue.dequeue()
ordered_list.append(tree_node_removed_from_queue.value)
if tree_node_removed_from_queue.left_node:
tree_node_queue.enqueue(tree_node_removed_from_queue.left_node)
if tree_node_removed_from_queue.right_node:
tree_node_queue.enqueue(
tree_node_removed_from_queue.right_node)
return ordered_list
def find_height(self):
height_counter = 0
marker= None
curr = self.root
queue = Queue()
queue.enqueue(curr)
check_queue = Queue()
while queue.is_empty():
curr=queue.dequeue()
if curr.child_left:
queue.enqueue(curr.child_left)
if curr.child_right:
queue.enqueue(curr.child_right)
if marker is curr.value:
marker= None
if marker is None:
if curr.child_left or curr.child_right:
if curr.child_left:
height_counter +=1
marker = curr.child_left.value
if curr.child_right:
marker = curr.child_right.value
height_counter +=1
return height_counter
def breadth_first(self, start):
"""This method does a breadth first traversal of a graph
Arguments:
node -- [starting poing of the traversal]
Returns:
[list] -- [a list of all connected nodes]
"""
explored = []
queue = Queue()
queue.enqueue(start)
while queue.peek() is not None:
node = queue.dequeue()
if node not in explored:
explored.append(node)
neighbors = self._graph[node]
for neighbor in neighbors:
queue.enqueue(neighbor[0])
return explored
def test_dequeue():
q = Queue()
q.enqueue('first value')
q.enqueue('second value')
assert q.dequeue() == 'first value'
def test_dequeue_empty_queue():
q = Queue()
assert q.dequeue() == 'this queue is empty buddy'
def test_dequeue_on_empty_raises_exception():
new_queue = Queue()
expected = 'Exception'
actual = new_queue.dequeue()
assert expected == actual
def test_dequeue_when_empty():
q = Queue()
with pytest.raises(InvalidOperationError):
q.dequeue()
def test_peek_empty_queue():
queue = Queue()
with pytest.raises(EmptyQueueException):
queue.peek()
with pytest.raises(EmptyQueueException):
queue.dequeue()
