def breadth_first(self, starting_point=None):
"""
This internal method is a generator that will output breadth first
traversal of a binary tree(left child, right child, parent),
one value at a time.
"""
if self.length == 0:
raise IndexError("You can't breadth-first traverse an empty Tree.")
from dll import DoublyLinkedList
unvisited = DoublyLinkedList()
if starting_point is None:
starting_point = self.root
elif self.contains(starting_point) is False:
raise IndexError('Starting point is not in the Tree.')
unvisited.push(starting_point)
visited = []
while unvisited.size() > 0:
current = unvisited.shift()
if current not in visited:
visited.append(current)
if current.left:
unvisited.push(current.left)
if current.right:
unvisited.push(current.right)
yield current.val
def breadth_first_traversal(self, starting_point):
"""Steps through the graph breadth-first.
Expects a starting point == value of a node in the graph."""
from dll import DoublyLinkedList
dll = DoublyLinkedList()
if self.has_node(starting_point) is False:
raise IndexError("That starting point is not in the graph.")
dll.push(starting_point)
result = []
while dll.size() > 0:
working_node = dll.shift()
if working_node not in result:
result.append(working_node)
for node in self.neighbors(working_node):
dll.push(node)
return result