Graph creation in Java

Question

What is the best way to construct a undirected graph in java? I need to create a graph so that i could run BFS and DFS on it.The graph should include information such as path cost and adjacent edges.

Answer 1

You can use available libraries. For example, JgraphT is a library which provides standard graph algorithms. JgraphT provides an iterator for doing BFS, see here. Here is an simple example:

SimpleWeightedGraph<Integer, DefaultWeightedEdge> graph = new SimpleWeightedGraph<>(DefaultWeightedEdge.class);

graph.addVertex(1);
graph.addVertex(2);
graph.addVertex(3);

DefaultWeightedEdge edge = graph.addEdge(1, 3);
graph.setEdgeWeight(edge, 11.22);

edge = graph.addEdge(3, 2);
graph.setEdgeWeight(edge, 44.33);

BreadthFirstIterator<Integer, DefaultWeightedEdge> it = new BreadthFirstIterator<>(graph);
for (; it.hasNext();) {
    Integer i = it.next();
    System.out.println("Node: " + i);
}