def arrival_departure_dfs(graph: Graph,
v: str,
discovered: Dict[str, bool],
arrival: Dict[str, int],
departure: Dict[str, int],
time: int) -> int:
"""
Method for DFS with arrival and departure times for each vertex
O(V+E) -- E could be as big as V^2
:param graph:
:param v:
:param discovered:
:param arrival:
:param departure:
:param time: should be initialized to -1
:return:
"""
time += 1
# when did we arrive at vertex 'v'?
arrival[v] = time
discovered[v] = True
for n in graph.get_neighbors(v):
if not discovered.get(n, False):
time = arrival_departure_dfs(graph, n, discovered, arrival, departure, time)
time += 1
# increment time and then set departure
departure[v] = time
return time
def mark_visited(g: Graph, v: str, v_map: Dict[str, bool],
t_sort_results: List[str]):
v_map[v] = True
for n in g.get_neighbors(v):
if not v_map[n]:
mark_visited(g, n, v_map, t_sort_results)
t_sort_results.append(v)
def test_get_neighbors(self):
json_graph = {"label": "my graph", "graph": {"A": ["B"], "B": []}}
graph = Graph(input_graph=json.dumps(json_graph))
self.assertEqual(graph.get_neighbors("A"), ["B"])
self.assertEqual(graph.get_neighbors("B"), [])
