Hello once again.

I wrote a program which uses Dijkstra's algorithm to give us the best weight path through an labyrinth (though every room has 2, 3 or 4 neighbours). Each room has it's weight. We simply create the labyrinth by command 'Graph graph = new Graph(n,m);'. Adding vertexes by 'graph.addVertex(position n, position m, weight);'. If you want to see a room and go through the labyrinth you must write 'graph.run(graph.vertexList[positon n][position m]);' - it should give the total weight of all visited rooms and the directions in which you should go. If you just want to go through you write: 'graph.Dijkstra(graph.vertexList[0][graph.n-1]);' since the entrance is always at [m][0] and the exit at [0][n]. To get the path in directions after command Dijkstra only 'graph.Path();'.

The problem is in the Graph.run command. It gives back good values for certain labyrinths, but for certain it does not. For example:

Works and gives back good values while:Code :

Graph graph2 = new Graph(4,4); graph2.addVertex(0,0,1); graph2.addVertex(1,0,1); graph2.addVertex(2,0,1); graph2.addVertex(3,0,1); graph2.addVertex(0,1,1); graph2.addVertex(1,1,9); graph2.addVertex(2,1,9); graph2.addVertex(3,1,9); graph2.addVertex(0,2,1); graph2.addVertex(1,2,1); graph2.addVertex(2,2,9); graph2.addVertex(3,2,9); graph2.addVertex(0,3,1); graph2.addVertex(1,3,9); graph2.addVertex(2,3,9); graph2.addVertex(3,3,9); graph2.run(graph2.vertexList[1][2]); graph2.run(graph2.vertexList[3][3]); graph2.Dijkstra(graph2.vertexList[0][graph2.n-1]); graph2.Path();

crashes at the 1st graph.run. It says that u is null. Well, I simply agree since I was debugging it and saw that it goes to null. The thing is I just can't get to the point where the problem is. I just don't get why it doesn't work.Code :

Graph graph = new Graph(7,5); graph.addVertex(0,0,0); graph.addVertex(1,0,5); graph.addVertex(2,0,25); graph.addVertex(3,0,20); graph.addVertex(4,0,75); graph.addVertex(5,0,0); graph.addVertex(6,0,50); graph.addVertex(0,1,20); graph.addVertex(1,1,80); graph.addVertex(2,1,60); graph.addVertex(3,1,10); graph.addVertex(4,1,25); graph.addVertex(5,1,35); graph.addVertex(6,1,120); graph.addVertex(0,2,10); graph.addVertex(1,2,15); graph.addVertex(2,2,75); graph.addVertex(3,2,25); graph.addVertex(4,2,40); graph.addVertex(5,2,70); graph.addVertex(6,2,100); graph.addVertex(0,3,70); graph.addVertex(1,3,25); graph.addVertex(2,3,150); graph.addVertex(3,3,10); graph.addVertex(4,3,100); graph.addVertex(5,3,5); graph.addVertex(6,3,80); graph.addVertex(0,4,50); graph.addVertex(1,4,0); graph.addVertex(2,4,170); graph.addVertex(3,4,5); graph.addVertex(4,4,0); graph.addVertex(5,4,10); graph.addVertex(6,4,30); graph.run(graph.vertexList[3][4]); graph.run(graph.vertexList[2][6]); graph.Dijkstra(graph.vertexList[0][graph.n-1]); graph.Path();

This is the whole project. It is written in NetBeans so I give you the whole folder with the classes. Attachment 1482

I'd reallly appreciate any help since my debugging can't do anything.

//EDIT: Don't know why but Dijkstra seems to stop before it gets to the final point. Think there must be something wrong with the method Dijkstra.