Shortest Path III
This is the final exercise of this trio! You're now going to complete the problem by writing the code that returns False if there's no path between two nodes.
This exercise is part of the course
Introduction to Network Analysis in Python
Exercise instructions
- Check to see if the queue has been emptied. You can do this by inspecting the last element of queue with
[-1]. - Place the appropriate return statement for indicating whether there's a path between these two nodes.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
def path_exists(G, node1, node2):
"""
This function checks whether a path exists between two nodes (node1, node2) in graph G.
"""
visited_nodes = set()
queue = [node1]
for node in queue:
neighbors = list(G.neighbors(node))
if node2 in neighbors:
print('Path exists between nodes {0} and {1}'.format(node1, node2))
return True
break
else:
visited_nodes.add(node)
queue.extend([n for n in neighbors if n not in visited_nodes])
# Check to see if the final element of the queue has been reached
if node == ____:
print('Path does not exist between nodes {0} and {1}'.format(node1, node2))
# Place the appropriate return statement
return ____