def get_longest_paths(graph: DiGraph, source: str) -> Dict[str, float]:
"""Get the length of the longest path to each node from a source node.
Parameters
----------
graph : networkx.classes.digraph.DiGraph
A directed graph.
source : str
The name of the source node.
Returns
-------
dict
A dictionary where keys are the names of the nodes in `graph` and
values are the lengths of the longest path from `source`.
"""
dist = {node: -float("inf") for node in graph}
dist[source] = 0
visited = []
for u in cyclic_topological_sort(graph, [source]):
visited.append(u)
for v in graph.neighbors(u):
if v in visited:
continue
if dist[v] < dist[u] + 1:
dist[v] = dist[u] + 1
return dist
def _visit(graph: DiGraph, node: T, order: List[T]) -> None:
if graph.nodes[node].get("visited", False):
return
graph.nodes[node]["visited"] = True
for n in graph.neighbors(node):
_visit(graph, n, order)
order.append(node)
def containing_bags(G: DiGraph, col: str) -> int:
return_val: int = 1
neighbor: str
for neighbor in G.neighbors(col):
return_val += containing_bags(G, neighbor) * \
G.get_edge_data(col, neighbor)["weight"]
return return_val
def create_graph_with_new_data():
'''
A DiGraph object holds directed edges
- Parallel edges still aren't allowed
- For a Digraph, two edges are parallel if they connect the same ordered pair of vertices
- Thus, two edges that connect the same vertices but go in different directions are not parallel
'''
# Create with edge list
g = DiGraph([(1, 5), (5, 1)])
#g = Graph([(1, 5), (5, 1)])
g.add_node(6)
print(g.nodes()) # [1, 5, 6]
# These are two distinct edges
print(g.edges()) # [(1, 5), (5, 1)]
print(g.neighbors(1)) # [5]
print(g.neighbors(5)) # [1]
g.edge[1][5]['foo'] = 'bar'
print(g.edge[1][5]) # {'foo': 'bar'}
print(g.edge[5][1]) # {}