def test_dequeue(self):
q = DeQueue(['A', 'B', 'C'])
assert q.dequeue_front() == 'A'
assert q.length() == 2
assert q.dequeue_back() == 'C'
assert q.length() == 1
assert q.dequeue_back() == 'B'
assert q.length() == 0
assert q.is_empty() is True
with self.assertRaises(ValueError):
q.dequeue_front()
def test_enqueue(self):
q = DeQueue()
q.enqueue_back('B')
assert q.front() == 'B'
assert q.length() == 1
q.enqueue_back('C')
assert q.front() == 'B'
assert q.length() == 2
q.enqueue_front('A')
assert q.front() == 'A'
assert q.length() == 3
assert q.is_empty() is False
def _traverse_level_order_iterative(self, start_node, visit):
"""Traverse this binary tree with iterative level-order traversal (BFS).
Start at the given node and visit each node with the given function.
Running time: O(n) Why and under what conditions?
Memory usage: O(n) Why and under what conditions?"""
# Create queue to store nodes not yet traversed in level-order
"""Remove and return the item at the back of this queue,"""
queue = DeQueue()
queue.enqueue_front(start_node)
while queue.is_empty() == False:
node = queue.dequeue_front()
visit(node.data)
if node.left != None:
queue.enqueue_back(node.left)
if node.right != None:
queue.enqueue_back(node.right)
def test_init_with_list(self):
q = DeQueue(['A', 'B', 'C'])
assert q.front() == 'A'
assert q.length() == 3
assert q.is_empty() is False
def test_init(self):
q = DeQueue()
assert q.front() is None
assert q.length() == 0
assert q.is_empty() is True