def dijkstra_shortest_paths(adj_list, node_from, infinity_value=0xFFFFFFFF):
distances = {k: infinity_value for k in get_nodes(adj_list)}
distances[node_from] = 0
visit_queue = IndexedHeap(distances)
next_edge, distance = visit_queue.pop_first()
while next_edge is not None:
for edge in get_edges_from(adj_list, next_edge):
if edge[0] in visit_queue and (distances[edge[0]] >
distance + edge[1]):
distances[edge[0]] = distance + edge[1]
visit_queue.update({edge[0]: distances[edge[0]]})
next_edge, distance = visit_queue.pop_first()
return distances
def test_heap_update():
test_values = {1: 'A', 2: 'B', 3: 'C'}
heap = IndexedHeap()
heap.update(test_values)
assert are_sorted_heaps_equal(
heap,
IndexedHeap(test_values),
), 'Two heaps should be equal'
heap.update(test_values)
heap.update({3: 'X', 4: 'Z'})
assert are_sorted_heaps_equal(
heap,
IndexedHeap({1: 'A', 2: 'B', 3: 'X', 4: 'Z'}),
), 'Two heaps should be equal'