def has_route2(digraph, node1, node2):
"""
Return True if node1 is connected node2 in graph, False otherwise.
User depth first search traversal method.
"""
if node1 == node2:
return True
# initialize visited booleans
visited = [False for _ in range(digraph.vertice_count())]
# initialize stack
stack = []
# mark starting node as visited
# get starting nodes neighbouring edges
# put these edges in stack
visited[node1] = True
curr = digraph.get_edges(node1)
while curr is not None:
stack.append(curr)
curr = curr.next
while len(stack) > 0:
vertex = stack.pop()
value = vertex.get_value()
if value == node2:
return True
elif not visited[value]:
visited[value] = True
curr = digraph.get_edges(value)
# auxillary stack to visit neighbours in the order they are in
# the adjacency list.
# alternatively, iterate throught the array in reverse but this
# is only to get the same output in number order
# otherwise this would not be necessary
adj_stack = []
while curr is not None:
if not visited[curr.get_value()]:
adj_stack.append(curr)
curr = curr.next
while len(adj_stack) > 0:
stack.append(adj_stack.pop())
return False
def has_route2(digraph, node1, node2):
"""
Return True if node1 is connected node2 in graph, False otherwise.
User depth first search traversal method.
"""
if node1 == node2:
return True
# initialize visited booleans
visited = [False for _ in range(digraph.vertice_count())]
# initialize stack
stack = []
# mark starting node as visited
# get starting nodes neighbouring edges
# put these edges in stack
visited[node1] = True
curr = digraph.get_edges(node1)
while curr is not None:
stack.append(curr)
curr = curr.next
while len(stack) > 0:
vertex = stack.pop()
value = vertex.get_value()
if value == node2:
return True
elif not visited[value]:
visited[value] = True
curr = digraph.get_edges(value)
# auxillary stack to visit neighbours in the order they are in
# the adjacency list.
# alternatively, iterate throught the array in reverse but this
# is only to get the same output in number order
# otherwise this would not be necessary
adj_stack = []
while curr is not None:
if not visited[curr.get_value()]:
adj_stack.append(curr)
curr = curr.next
while len(adj_stack) > 0:
stack.append(adj_stack.pop())
return False
def has_route(digraph, node1, node2):
"""
Return True if node1 is connected to node2 in graph, False otherwise.
Use breadth first search traversal method.
"""
if node1 == node2:
return True
# initialize visited booleans
visited = [False for _ in range(digraph.vertice_count())]
# initialize queue
queue = []
# add starting node to queue FIFO
# while loop terminates when queue is 0
# pop queue to variable
# if variable is node2:
# return True
# if variable not visited:
# visit node
# mark node as visited
# return False
visited[node1] = True
curr = digraph.get_edges(node1)
while curr is not None:
queue.append(curr)
curr = curr.next
while len(queue) > 0:
vertex = queue.pop(0)
value = vertex.get_value()
if vertex.get_value() == node2:
return True
elif not visited[value]:
visited[value] = True
curr = digraph.get_edges(value)
while curr is not None:
queue.append(curr)
curr = curr.next
return False
def has_route(digraph, node1, node2):
"""
Return True if node1 is connected to node2 in graph, False otherwise.
Use breadth first search traversal method.
"""
if node1 == node2:
return True
# initialize visited booleans
visited = [False for _ in range(digraph.vertice_count())]
# initialize queue
queue = []
# add starting node to queue FIFO
# while loop terminates when queue is 0
# pop queue to variable
# if variable is node2:
# return True
# if variable not visited:
# visit node
# mark node as visited
# return False
visited[node1] = True
curr = digraph.get_edges(node1)
while curr is not None:
queue.append(curr)
curr = curr.next
while len(queue) > 0:
vertex = queue.pop(0)
value = vertex.get_value()
if vertex.get_value() == node2:
return True
elif not visited[value]:
visited[value] = True
curr = digraph.get_edges(value)
while curr is not None:
queue.append(curr)
curr = curr.next
return False