class StackUsingQueue(object):
def __init__(self):
self._queue_one = Queue()
self._queue_two = Queue()
def __str__(self):
return self._queue_one.__str__()
def push(self, element):
'''
:param element: element to be pushed onto stack
'''
while not self._queue_one.is_empty():
self._queue_two.enqueue(self._queue_one.dequeue())
self._queue_one.enqueue(element)
while not self._queue_two.is_empty():
self._queue_one.enqueue(self._queue_two.dequeue())
return
def pop(self):
return self._queue_one.dequeue()
def level_order_traverse(root):
if root is None:
return
queue = Queue()
queue.enqueue(root)
while not queue.is_empty():
node = queue.dequeue()
print node,
if node.lchild is not None:
queue.enqueue(node.lchild)
if node.rchild is not None:
queue.enqueue(node.rchild)
print
def test_enqueue_five_elements_to_queue_and_dequeue_all_elements(self):
queue = Queue()
langs = ['python', 'java', 'ruby', 'php', 'go']
for lang in langs:
queue.enqueue(lang)
self.assertEqual(len(langs), queue.size())
element1 = queue.dequeue()
element2 = queue.dequeue()
element3 = queue.dequeue()
element4 = queue.dequeue()
element5 = queue.dequeue()
self.assertEqual('python', element1)
self.assertEqual('java', element2)
self.assertEqual('ruby', element3)
self.assertEqual('php', element4)
self.assertEqual('go', element5)
self.assertTrue(queue.is_empty())
def test_no_element_in_queue(self):
queue = Queue()
self.assertTrue(queue.is_empty())
