This notebook was prepared by Donne Martin. Source and license info is on GitHub.
Input:
add_edge(source, destination, weight)
graph.add_edge(0, 1)
graph.add_edge(0, 4)
graph.add_edge(0, 5)
graph.add_edge(1, 3)
graph.add_edge(1, 4)
graph.add_edge(2, 1)
graph.add_edge(3, 2)
graph.add_edge(3, 4)
Result:
Refer to the Solution Notebook. If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.
%run ../graph/graph.py
%load ../graph/graph.py
class GraphShortestPath(Graph):
def shortest_path(self, source_key, dest_key):
# TODO: Implement me
pass
The following unit test is expected to fail until you solve the challenge.
# %load test_shortest_path.py
import unittest
class TestShortestPath(unittest.TestCase):
def test_shortest_path(self):
nodes = []
graph = GraphShortestPath()
for id in range(0, 6):
nodes.append(graph.add_node(id))
graph.add_edge(0, 1)
graph.add_edge(0, 4)
graph.add_edge(0, 5)
graph.add_edge(1, 3)
graph.add_edge(1, 4)
graph.add_edge(2, 1)
graph.add_edge(3, 2)
graph.add_edge(3, 4)
self.assertEqual(graph.shortest_path(nodes[0].key, nodes[2].key), [0, 1, 3, 2])
self.assertEqual(graph.shortest_path(nodes[0].key, nodes[0].key), [0])
self.assertEqual(graph.shortest_path(nodes[4].key, nodes[5].key), None)
print('Success: test_shortest_path')
def main():
test = TestShortestPath()
test.test_shortest_path()
if __name__ == '__main__':
main()
Review the Solution Notebook for a discussion on algorithms and code solutions.