/** Does not handle Graphs of 1 or fewer nodes */
public Graph kruskal(Graph g) {
boolean add = false;
Graph mst = new Graph(); // initialize graph
Vector edges = g.getEdges(); // get edges
Collections.sort(edges); // sort edges
// find mst
for (int i = 0; i < edges.size(); ++i) {
Edge edge = (Edge) edges.get(i); // get edge
KNode[] ends = edge.getEnds(); // get ends
if (!mst.containsNode(ends[0])) {
mst.addNode(ends[0]); // check for first end
add = true;
}
if (!mst.containsNode(ends[1])) {
mst.addNode(ends[1]); // check other end
add = true;
}
if (add) // if either end is new add edge
{
mst.addEdge(edge);
add = false;
} else // ensure trees are connected if nodes are contained
{
if (!mst.pathBetween(ends)) mst.addEdge(edge);
}
}
return mst;
}
