%run ../graph/graph.py
%load ../graph/graph.py

def dfs(root, visit_func):
    # TODO: Implement me
    pass

"""
Explanation: <small><i>This notebook was prepared by Donne Martin. Source and license info is on GitHub.</i></small>
Challenge Notebook
Problem: Implement depth-first search on a graph.

Constraints
Test Cases
Algorithm
Code
Unit Test
Solution Notebook

Constraints

Is the graph directed?
Yes


Can we assume we already have Graph and Node classes?
Yes



Test Cases
Input:
* add_edge(source, destination, weight)
graph.add_edge(0, 1, 5)
graph.add_edge(0, 4, 3)
graph.add_edge(0, 5, 2)
graph.add_edge(1, 3, 5)
graph.add_edge(1, 4, 4)
graph.add_edge(2, 1, 6)
graph.add_edge(3, 2, 7)
graph.add_edge(3, 4, 8)
Result:
* Order of nodes visited: [0, 1, 3, 2, 4, 5]
Algorithm
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.
Code
End of explanation
"""


%run ../utils/results.py

# %load test_dfs.py
from nose.tools import assert_equal


class TestDfs(object):

    def __init__(self):
        self.results = Results()

    def test_dfs(self):
        nodes = []
        graph = Graph()
        for id in range(0, 6):
            nodes.append(graph.add_node(id))
        graph.add_edge(0, 1, 5)
        graph.add_edge(0, 4, 3)
        graph.add_edge(0, 5, 2)
        graph.add_edge(1, 3, 5)
        graph.add_edge(1, 4, 4)
        graph.add_edge(2, 1, 6)
        graph.add_edge(3, 2, 7)
        graph.add_edge(3, 4, 8)
        dfs(nodes[0], self.results.add_result)
        assert_equal(str(self.results), "[0, 1, 3, 2, 4, 5]")

        print('Success: test_dfs')


def main():
    test = TestDfs()
    test.test_dfs()


if __name__ == '__main__':
    main()

"""
Explanation: Unit Test
The following unit test is expected to fail until you solve the challenge.
End of explanation
"""


