def dijkstra(self, start, end):
if start not in self.vertices or end not in self.vertices:
return
self.clean_vertices()
start_vertex = self.get_vertex(start)
end_vertex = self.get_vertex(end)
for v in self.get_vertices():
v.distance = sys.maxsize
start_vertex.distance = 0
pq = BinaryHeap()
pq.build_heap([(v.distance, v) for v in self.get_vertices()])
while pq.size() > 0:
current = pq.delete_min()
current = current[1] # get the vertex from the tuple
for neighbor in current.get_connections():
new_distance = current.distance + current.get_connection_weight(
neighbor)
if new_distance < neighbor.distance:
neighbor.distance = new_distance
neighbor.predecessor = current
pq.rebuild_heap()
items = []
trace_vertex = end_vertex
done = False
while not done:
items.append(trace_vertex.get_id())
if trace_vertex.get_id() == start_vertex.get_id():
done = True
trace_vertex = trace_vertex.predecessor
items.reverse()
print("\nResult from dijkstra: {0}\n".format(" => ".join(items)))
return items
def dijkstra(self, start, end):
if start not in self.vertices or end not in self.vertices:
return
self.clean_vertices()
start_vertex = self.get_vertex(start)
end_vertex = self.get_vertex(end)
for v in self.get_vertices():
v.distance = sys.maxsize
start_vertex.distance = 0
pq = BinaryHeap()
pq.build_heap([(v.distance, v) for v in self.get_vertices()])
while pq.size() > 0:
current = pq.delete_min()
current = current[1] # get the vertex from the tuple
for neighbor in current.get_connections():
new_distance = current.distance + current.get_connection_weight(neighbor)
if new_distance < neighbor.distance:
neighbor.distance = new_distance
neighbor.predecessor = current
pq.rebuild_heap()
items = []
trace_vertex = end_vertex
done = False
while not done:
items.append(trace_vertex.get_id())
if trace_vertex.get_id() == start_vertex.get_id():
done = True
trace_vertex = trace_vertex.predecessor
items.reverse()
print("\nResult from dijkstra: {0}\n".format(" => ".join(items)))
return items
def testBinaryHeap(self):
heap = BinaryHeap()
self.assertTrue(heap.is_empty())
heap.insert(1)
heap.insert(4)
heap.insert(5)
heap.insert(3)
heap.insert(2)
heap.insert(6)
heap.delete_min()
self.assertEqual(heap.find_min(), 2)
self.assertEqual(heap.size(), 5)
self.assertFalse(heap.is_empty())
heap.build_heap([99, 77, 33, 22, 55, 66, 11, 44, 99])
self.assertEqual(heap.find_min(), 11)
self.assertEqual(heap.size(), 9)
self.assertFalse(heap.is_empty())
def testBinaryHeap(self):
heap = BinaryHeap()
self.assertTrue(heap.is_empty())
heap.insert(1)
heap.insert(4)
heap.insert(5)
heap.insert(3)
heap.insert(2)
heap.insert(6)
heap.delete_min()
self.assertEqual(heap.find_min(), 2)
self.assertEqual(heap.size(), 5)
self.assertFalse(heap.is_empty())
heap.build_heap([99, 77, 33, 22, 55, 66, 11, 44, 99])
self.assertEqual(heap.find_min(), 11)
self.assertEqual(heap.size(), 9)
self.assertFalse(heap.is_empty())
