Node 5 is contained in the shortest path between 1 and 15. Node 5 is determined as 5, the hop_count should be added 1 since When node 5 is explored and the shortest distance between node 1 and.Node 2 is not contained in the shortest path between 1 and 15. Node 2 is determined as 3, the hop_count cannot be added 1 since When node 2 is explored and the shortest distance between node 1 and.To better define the problem, as shown in this figure, the red line is the shortest path between node 1 and node 15, the shortest path is 1 ->5 ->8 ->7 ->10 ->13 ->15. In summary, if we want to know the current hop-count during Dijkstra is running, we need to set hop_count +1, When the shortest path from the parent_node to the neighbor_node has been determined, and the neighbor_node will be included to the shortest path from the source to the destination node. Only condition 1 is not enough, even we can know when Dijkstra has found the shortest distance between two nodes, but how do we know whether the neighbor_node will be included in the shortest path between a given source and destination?.
#1 HOP VERTEX COVER HOW TO#
How to determine Dijkstra has already found the shortest distance between a parent_node and a neighbor_node? But, Dijkstra finds the shortest path by iterating the neighbor nodes, and the array that stores the shortest distance is updated gradually during path searching.
In my opinion, there are two significant issues that need to be addressed. I know this is incorrect since when Dijkstra iterates the neighbor, I make hop_cout + 1 that represents the number of explored nodes rather than the hop_count. The graph of adjList is as shown: (the red line is the shortest path from 1 to 15) Print("found shortest path ".format(path, dist)) Heappush(heap, (distance + cost, neighbor, current))įlag, dist, path = dijkstra(adjList,1,15) If sink and current = sink: # only correct place to have terminating conditionįor (neighbor, cost) in adjList: Parent = came_from # this also marks the node as visited If parent is not None: # skip if already visited However, during the Dijkstra's path searching, can we count the hop between a given source and? from heapq import heappop, heappushĭistance, current, came_from = heappop(heap) Hop is defined as the (N - 1), where N is the number of vertices contained in the shortest paths.Ībsolutely, after finding the shortest path, we can easily count the hop number. Moreover, I tried to count the hop when performing the Dijkstra to find the shortest path, when the hop-count exceeds the pre-defined Max_hop, the Dijkstra will be terminated, but I was failed. Thank the codes from I can modify the Dijkstra to obtain the shortest path between a given source node and destination node.
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