def cycles(graph):
union_find = UnionFind()
new = {}
for v in graph:
new_edges = []
set_v = union_find.make_set(v)
for u in graph[v]:
new_edges.append(union_find.make_set(u))
new[set_v] = new_edges
for u_ in new:
for v_ in new[u_]:
if union_find.find_set(u_) == union_find.find_set(v_):
return True
else:
union_find.union(u_, v_)
return False
def kruskals(graph):
"""
:param graph: undigraph
:return:
"""
T = set() # empty edge set
union_find = UnionFind()
new = {}
for v in graph:
new_edges = []
set_v = union_find.make_set(v)
for u, w in graph[v]:
new_edges.append((union_find.make_set(u), w))
new[set_v] = new_edges
edges = [(u, v[0], v[1]) for u in new for v in new[u]]
edges.sort(key=lambda x: x[-1])
for u, v, _ in edges:
if union_find.find_set(u) != union_find.find_set(v):
T.add((union_find.get_key(u), union_find.get_key(v)))
union_find.union(u, v)
return T