java - Dijkstra with a heap. How to update the heap after relaxation? -

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i trying implement dijkstra algorithm.

 foreach distance d    d = infinity  d[source] = 0   create_heap_based_on_distances();   while(true)    bestedge = heap[0]     remove_minimum_from_heap //it heap[0]     foreach adjacency of bestedge       if (weight + bestedge_distance < current_distance)       {           current_distance = weight + bestedge_distance            // have update heap, how can that?       }    if (heap_empty) break

so, in relaxation, how can update heap, have correct order? don't have heap's index node in step. mean have create new array nodes[edge] = heapindex, heap's index node? seems inefficient need update insert_to_heap, remove_minimum functions.

c or java code okay.

does mean have create new array nodes[edge] = heapindex, heap's index node?

yes.

but seems inefficient need update insert_to_heap, remove_minimum functions.

array updates cheap, both in theory , in practice, , have few of per heap operation, not inefficient @ all. also, memory usage of such array cheap compared storage cost of graph data structure.


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