# has_bridges#

has_bridges(G, root=None)[source]#

Decide whether a graph has any bridges.

A bridge in a graph is an edge whose removal causes the number of connected components of the graph to increase.

Parameters:
Gundirected graph
rootnode (optional)

A node in the graph G. If specified, only the bridges in the connected component containing this node will be considered.

Returns:
bool

Whether the graph (or the connected component containing root) has any bridges.

Raises:
NodeNotFound

If root is not in the graph G.

NetworkXNotImplemented

If G is a directed graph.

Notes

This implementation uses the networkx.bridges() function, so it shares its worst-case time complexity, $$O(m + n)$$, ignoring polylogarithmic factors, where $$n$$ is the number of nodes in the graph and $$m$$ is the number of edges.

Examples

The barbell graph with parameter zero has a single bridge:

>>> G = nx.barbell_graph(10, 0)
>>> nx.has_bridges(G)
True


On the other hand, the cycle graph has no bridges:

>>> G = nx.cycle_graph(5)
>>> nx.has_bridges(G)
False