def test_queue(self):
queue = Queue()
self.assertEqual(queue.is_empty(), True)
self.assertEqual(queue.peek(), None)
queue.queue("first_in_line")
self.assertEqual(queue.peek(), "first_in_line")
self.assertEqual(queue.is_empty(), False)
queue.queue("second_in_line")
self.assertEqual(queue.de_queue(), "first_in_line")
self.assertEqual(queue.peek(), "second_in_line")
self.assertEqual(queue.de_queue(), "second_in_line")
self.assertEqual(queue.is_empty(), True)
self.assertEqual(queue.peek(), None)
def traversal_level_order(self):
# o(n) for time
# o(n) for space
if self.root is None:
return
node_queue = Queue()
node_queue.queue(self.root)
value = []
while not node_queue.is_empty():
current_node = node_queue.de_queue()
value.append(current_node.value)
if current_node.left is not None:
node_queue.queue(current_node.left)
if current_node.right is not None:
node_queue.queue(current_node.right)
return value