java Dijkstra最短的路径如何找出最终目的地？

Question

I am trying to learn graphs as well using Dijkstra's path and am using this geeks for geeks tutorial . I think i understand how it works using weight to find the shortest path. However this may be dumb but i dont understand how to find the destination point by looking at the code. or how the 9 inputs are

Why are there 9 inputs cant it work with only three? And how does the program know where to end?

Answer 1

The program in that example ends when all nodes have been visited, it does not choose a specific destination. It calculates the minimum distance (and path) from node 0 to every node in the graph.

There are 9 nodes in the example, but ofcourse you can also use 3 nodes, or 1000 nodes..

Answer 2

So, to address the first half of your question, there isn't a predetermined "destination node" with Dijsktra's algorithm, moreso just a final result.

In this example from the GeeksforGeeks code,

void dijkstra(int graph[V][V], int src) 

We can see that the algorithm wants an array of all of the nodes, and which node you'll be starting from. Each node in this array has 9 inputs which correspond to that node's given distance from any other node, where a value of 0 represents no connection. For example, the "0" node has values:

{0, 4, 0, 0, 0, 0, 0, 8, 0}

Which mean that node 0 is 4 units away from node 1, 8 units away from node 7, and either has no connection to, or IS one of the other 7 nodes. If you only have 3 nodes, then you'd use 3 inputs to represent the possible distances between all 3.

When the program has exhausted all possible nodes and paths, the algorithm will stop. This algorithm looks for a minimum spanning tree, not a path from point A to point B.