def test_inverse(self):
"""Tests that the encoding and decoding functions are inverses."""
for T in nx.nonisomorphic_trees(4):
T2 = nx.from_prufer_sequence(nx.to_prufer_sequence(T))
assert_nodes_equal(list(T), list(T2))
assert_edges_equal(list(T.edges()), list(T2.edges()))
for seq in product(range(4), repeat=2):
seq2 = nx.to_prufer_sequence(nx.from_prufer_sequence(seq))
assert list(seq) == seq2
def test_inverse(self):
"""Tests that the encoding and decoding functions are inverses.
"""
for T in nx.nonisomorphic_trees(4):
T2 = nx.from_prufer_sequence(nx.to_prufer_sequence(T))
assert_equal(list(T), list(T2))
assert_equal(list(T.edges()), list(T2.edges()))
for seq in product(range(4), repeat=2):
seq2 = nx.to_prufer_sequence(nx.from_prufer_sequence(seq))
assert_equal(list(seq), seq2)
def test_encoding(self):
"""Tests for encoding a tree as a Prüfer sequence using the
iterative strategy.
"""
# Example from Wikipedia.
tree = nx.Graph([(0, 3), (1, 3), (2, 3), (3, 4), (4, 5)])
sequence = nx.to_prufer_sequence(tree)
assert_equal(sequence, [3, 3, 3, 4])
def task_q(spantree):
new_labels = dict()
i = 0
for node in spantree.nodes:
new_labels[node] = i
i+=1
spntr = nx.relabel_nodes(spantree, new_labels)
prufer = nx.to_prufer_sequence(spntr)
print("Prufer code: " + str(prufer))
def test_encoding(self):
"""Tests for encoding a tree as a Prüfer sequence using the
iterative strategy.
"""
# Example from Wikipedia.
tree = nx.Graph([(0, 3), (1, 3), (2, 3), (3, 4), (4, 5)])
sequence = nx.to_prufer_sequence(tree)
assert sequence == [3, 3, 3, 4]
def solve_q(G):
mst = solve_o(G, show_the_tree=False)
new_mst = nx.Graph()
new_nodes = dict()
i = 0
for node in mst.nodes:
new_nodes[node] = i
i += 1
for edge in mst.edges:
new_mst.add_edge(new_nodes[edge[0]], new_nodes[edge[1]])
prufer = nx.to_prufer_sequence(new_mst)
correct_prufer = list()
for number in prufer:
correct_prufer.append(
list(new_nodes.keys())[list(new_nodes.values()).index(number)])
print(len(prufer))
print(prufer)
print(correct_prufer)
def solve(n, m, edges):
def find(v):
nonlocal parent
while (v != parent[v]):
v = parent[v]
return v
def jopa(v1, v2):
return find(v1) == find(v2)
def union():
nonlocal parent, rank, a, b, c, answer
v1 = find(a)
v2 = find(b)
if rank[v1] > rank[v2]:
v1, v2 = v2, v1
rank[v2] += rank[v1]
parent[v1] = v2
parent = [i for i in range(n)]
rank = [1] * n
answer = 0
answer_edges = []
for i in range(m):
a, b, c = edges[i]
if not jopa(a, b):
union()
answer += c
answer_edges.append([a, b])
# Получим код Прюфера
G_new = nx.Graph()
G_new.add_edges_from(answer_edges)
prufer_code = nx.to_prufer_sequence(G_new)
# Переведём num вершин в name и посмотрим на них
for i in prufer_code:
print(country[i], end=', ')
def test_null_graph(self):
nx.to_prufer_sequence(nx.null_graph())
def test_nontree(self):
G = nx.cycle_graph(3)
nx.to_prufer_sequence(G)
def test_trivial_graph(self):
with pytest.raises(nx.NetworkXPointlessConcept):
nx.to_prufer_sequence(nx.trivial_graph())
def test_bad_integer_labels(self):
with pytest.raises(KeyError):
T = nx.Graph(nx.utils.pairwise("abc"))
nx.to_prufer_sequence(T)
def test_bad_integer_labels(self):
T = nx.Graph(nx.utils.pairwise('abc'))
nx.to_prufer_sequence(T)
def test_nontree(self):
with pytest.raises(nx.NotATree):
G = nx.cycle_graph(3)
nx.to_prufer_sequence(G)
def test_trivial_graph(self):
nx.to_prufer_sequence(nx.trivial_graph())
def test_null_graph(self):
nx.to_prufer_sequence(nx.null_graph())
def test_nontree(self):
G = nx.cycle_graph(3)
nx.to_prufer_sequence(G)
def test_trivial_graph(self):
nx.to_prufer_sequence(nx.trivial_graph())
def test_bad_integer_labels(self):
T = nx.Graph(nx.utils.pairwise('abc'))
nx.to_prufer_sequence(T)