def test_post_order_dfs_traversal__tree_3__non_root_node(tree_3):
expected_labels = {("e", "d", "c"), ("d", "e", "c")}
nodes = traversals.post_order_dfs_traversal(tree_3.get_node("c"))
actual_labels = tuple(node.label for node in nodes)
assert actual_labels in expected_labels
def test_post_order_dfs_traversal__edge_into_three_cycle__root_node(
edge_into_three_cycle, ):
nodes = traversals.post_order_dfs_traversal(
edge_into_three_cycle.get_node("w"))
actual_labels = tuple(node.label for node in nodes)
assert actual_labels == ("z", "y", "x", "w")
def test_post_order_dfs_traversal__tree_4__non_root_node_all(tree_4):
expected_labels = {("c", "e", "d", "a", "b"), ("e", "d", "a", "c", "b")}
nodes = traversals.post_order_dfs_traversal(tree_4.get_node("b"),
ignore_directionality=True)
actual_labels = tuple(node.label for node in nodes)
assert actual_labels in expected_labels
def optimal_sort_for_trees(
graph: datastructures.Tree) -> datastructures.OrderedTree:
graph_reversed = False
if graph.is_in_tree():
graph.reverse()
graph_reversed = True
node_to_descendents_count = {}
for node in traversals.post_order_dfs_traversal(graph.root):
node_to_descendents_count[node] = 1 + sum(
node_to_descendents_count[child_node]
for child_node in node.out_nodes)
ordered_graph = datastructures.OrderedTree(
graph,
traversals.pre_order_dfs_traversal(
graph.root, sorting_key=node_to_descendents_count.get),
)
if graph_reversed:
ordered_graph.reverse()
return ordered_graph
def test_post_order_dfs_traversal__tree_4__root_node__with_sorting(tree_4):
nodes = traversals.post_order_dfs_traversal(
tree_4.get_node("a"), sorting_key=lambda node: node.label)
actual_labels = tuple(node.label for node in nodes)
assert actual_labels == ("c", "b", "e", "d", "a")
def test_post_order_dfs_traversal__tree_3__non_root_node__reverse(tree_3):
tree_3.reverse()
nodes = traversals.post_order_dfs_traversal(tree_3.get_node("c"))
actual_labels = tuple(node.label for node in nodes)
assert actual_labels == ("a", "b", "c")