class TestGraph(unittest.TestCase):
def setUp(self):
self.undirected = UndirectedGraph()
self.undirected.add_edge(1, 2, 2)
self.undirected.add_edge(1, 3, 6)
self.undirected.add_edge(2, 3, 3)
self.undirected.add_edge(2, 4, 1)
self.undirected.add_edge(3, 4, 1)
self.undirected.add_edge(3, 5, 4)
self.undirected.add_edge(4, 5, 6)
self.directed = DirectedGraph()
self.directed.add_edge(1, 2, 2)
self.directed.add_edge(1, 3, 6)
self.directed.add_edge(2, 3, 3)
self.directed.add_edge(2, 4, 1)
self.directed.add_edge(3, 4, 1)
self.directed.add_edge(3, 5, 4)
self.directed.add_edge(4, 5, 6)
def test_get_edges(self):
assert self.undirected.get_all_edges() == self.directed.get_all_edges()
assert self.undirected.get_vertices() == self.directed.get_vertices()
def test_directed_graph(self):
assert len(self.directed.get_successive_vertices(4)) == 1
assert len(self.undirected.get_successive_vertices(4)) == 3
assert self.undirected.edge_exists(4, 3)
assert not self.directed.edge_exists(4, 3)
self.directed.delete_edge(4, 3)
self.undirected.delete_edge(4, 3)
assert len(self.directed.get_all_edges()) == len(self.undirected.get_all_edges()) + 1
def test_undirected_graph(self):
g = UndirectedGraph()
class TestGraph(unittest.TestCase):
def setUp(self):
self.undirected = UndirectedGraph()
self.undirected.add_edge(1, 2, 2)
self.undirected.add_edge(1, 3, 6)
self.undirected.add_edge(2, 3, 3)
self.undirected.add_edge(2, 4, 1)
self.undirected.add_edge(3, 4, 1)
self.undirected.add_edge(3, 5, 4)
self.undirected.add_edge(4, 5, 6)
self.directed = DirectedGraph()
self.directed.add_edge(1, 2, 2)
self.directed.add_edge(1, 3, 6)
self.directed.add_edge(2, 3, 3)
self.directed.add_edge(2, 4, 1)
self.directed.add_edge(3, 4, 1)
self.directed.add_edge(3, 5, 4)
self.directed.add_edge(4, 5, 6)
def test_get_edges(self):
assert self.undirected.get_all_edges() == self.directed.get_all_edges()
assert self.undirected.get_vertices() == self.directed.get_vertices()
def test_directed_graph(self):
assert len(self.directed.get_successive_vertices(4)) == 1
assert len(self.undirected.get_successive_vertices(4)) == 3
assert self.undirected.edge_exists(4, 3)
assert not self.directed.edge_exists(4, 3)
self.directed.delete_edge(4, 3)
self.undirected.delete_edge(4, 3)
assert len(self.directed.get_all_edges()) == len(
self.undirected.get_all_edges()) + 1
def test_undirected_graph(self):
g = UndirectedGraph()
def kruskal(graph: UndirectedGraph) -> UndirectedGraph:
"""
Kruskal's algorithm is a minimum-spanning-tree algorithm which finds an edge of the least possible weight
that connects any two trees in the forest. It is a greedy algorithm in graph theory as it finds a minimum
spanning tree for a connected weighted undirected graph adding increasing cost arcs at each step.
Time complexity: O(E log V)
"""
spanning_tree = UndirectedGraph()
union_find = UnionFind(max(graph.get_vertices()) + 1)
heap = FibonacciHeap(graph.get_all_edges())
while not heap.is_empty():
edge = heap.pop()
# Only add the edge if it will not create a cycle
if union_find.find(edge.a) != union_find.find(edge.b):
spanning_tree.add_edge(edge.a, edge.b, edge.weight)
union_find.union(edge.a, edge.b)
return spanning_tree
