def compute_resilience(ugraph, attack_order):
"""
a function to test the resiliency of a graph by removing nodes/edges
:rtype : list
:param ugraph:
:param attack_order:
:return:
"""
# copy the graph
graph = copy_graph(ugraph)
# get all connected components of ugraph and add to list
lcc = [largest_cc_size(graph)]
# loop through each attack
for attack in attack_order:
# remove the node
edges = graph.pop(attack)
# remove edges from other nodes
for node in edges:
graph[node].discard(attack)
# calculate largest connected component
lcc.append(largest_cc_size(graph))
return lcc
def fast_targeted_order(graph):
"""
Compute a targeted attack order consisting of nodes of maximal degree
:rtype : list
:param ugraph: input graph
"""
# copy graph
graph = provided.copy_graph(graph)
# initialize return variable
attack_order = []
# initialize array
degree_sets = {}
for itr in xrange(len(graph)):
degree_sets[itr] = set()
for idx in graph:
degree_sets[len(graph[idx])].add(idx)
rev_degrees = degree_sets.keys()
rev_degrees.reverse()
for idx in rev_degrees:
while degree_sets[idx]:
u = degree_sets[idx].pop()
for neighbour in graph[u]:
d = len(graph[neighbour])
degree_sets[d].remove(neighbour)
degree_sets[d - 1].add(neighbour)
attack_order.append(u)
provided.delete_node(graph, u)
return attack_order
