def levelorder(self):
items = []
queue = Queue()
node = self._root # starting from the root
queue.insert(node) # insert it
while not queue.is_empty():
node = queue.remove() # pick that node
items.append(node._data) # add to the list
# if the left side is not None, there exist a left side, add the queue (going left to right_
if node._left is not None:
queue.insert(node._left)
# you also want to add the right side
if node._right is not None:
queue.insert(node._right)
return items
def __str__(self):
"""
-------------------------------------------------------
Description:
Returns a string representation of bst
Uses Breadth First Search (BFS)
Assert: none
Use: str(bst) or print(bst)
-------------------------------------------------------
Parameters:
None
Returns:
output: string representation of bst (str)
-------------------------------------------------------
"""
q = Queue(self.MAX_SIZE)
output = ''
q.insert(self._root)
level = 1
while not q.is_empty():
node = q.remove()
if node is None:
continue
node_level = self.level(node._data)
if node_level == level:
output += '{} '.format(str(node._data))
elif node_level > level:
output = '{}\n'.format(output[:-1])
output += '{} '.format(str(node._data))
level += 1
if node._left is not None:
q.insert(node._left)
if node._right is not None:
q.insert(node._right)
return output[:-1]
def _reflect_vertical_aux(self, node):
queue = Queue()
tree = BST()
if node is None:
return tree
if node is not None:
queue.insert(node)
while not queue.is_empty():
temp = node._left
node._left = node._right
node._right = temp
node = queue.remove()
tree.insert(node._data)
if node._left is not None:
queue.insert(node._left)
if node._right is not None:
queue.insert(node._right)
return tree
def __str__(self):
"""
-------------------------------------------------------
Description:
Returns a string representation of bst
Uses Breadth First Search (BFS)
Assert: none
Use: str(bst) or print(bst)
-------------------------------------------------------
Parameters:
None
Returns:
output: string representation of bst (str)
-------------------------------------------------------
"""
# You can all the way down print the depth (DFS depth first search) --> Stacks
# Horizontal search, reads horizontally to prints (BFS breath first search) --> Queues
q = Queue(self.MAX_SIZE)
output = ''
q.insert(self._root)
level = 1
# come back to this in WEEK #11
while not q.is_empty():
node = q.remove()
if node is None:
continue
node_level = self.level(node._data)
if node_level == level:
output += str(node._data) + ' '
elif node_level > level:
output = output[:-1] + '\n'
output += str(node._data) + ' '
level += 1
if node._left is not None:
q.insert(node._left)
if node._right is not None:
q.insert(node._right)
return output[:-1]
def reverse_stack(stack):
"""
-------------------------------------------------------
Description:
Reverse a stack using a queue
Use: reverse_stack(stack)
-------------------------------------------------------
Parameters:
stack - a stack of items (Stack)
Returns:
No returns
-------------------------------------------------------
"""
queue = Queue()
while not stack.is_empty():
item = deepcopy(stack.pop())
queue.insert(item)
while not queue.is_empty():
stack.push(queue.remove())
return
print(lis.pop_front())
print("container of size: " + str(lis.get_size()) + ":")
print(lis)
print(lis.pop_front())
print(lis.pop_front())
print("container of size: " + str(lis.get_size()) + ":")
print(lis)
print("\nTESTING QUEUE WITH ARRAYS\n")
queue = Queue("array")
queue.add(2)
queue.add(4)
queue.add(7)
print("the data structure is of size: " + str(queue.get_size()))
print(queue.remove())
print(queue.remove())
print(queue.remove())
print(queue.remove())
print("the data structure is of size: " + str(queue.get_size()))
print("\nTESTING STACK WITH ARRAYS\n")
stack = Stack("array")
stack.push(2)
stack.push(4)
stack.push(7)
print("the data structure is of size: " + str(stack.get_size()))
print(stack.pop())
print(stack.pop())
print(stack.pop())
result = q.insert(-1) assert (result == True) assert (not q.is_empty()) assert (q.__str__() == "-1 7 5") result = q.insert(20) assert (result == False) assert (not q.is_empty()) assert (q.__str__() == "-1 7 5") result = q.insert(33) assert (result == False) assert (not q.is_empty()) assert (q.__str__() == "-1 7 5") x = q.remove() assert (not q.is_empty()) assert (q.__str__() == "-1 7") assert (x == 5) x = q.remove() assert (not q.is_empty()) assert (q.__str__() == "-1") assert (x == 7) q.insert(11) assert (not q.is_empty()) assert (q.__str__() == "11 -1") x = q.remove() assert (not q.is_empty())
