// inserts a undirected edge into the graph
public void addEdge(UndirectedEdge e) {
int v = e.either();
int w = e.other(v);
adj[v].add(e);
adj[w].add(e);
edges++;
}
/**
* Given the edge-weighted graph, it find the minimum spanning tree and its weight.
*
* @param graph
*/
public KruskalMinimumSpanningTree(EdgeWeightedUndirectedGraph graph) {
MinimumPriorityQueue minEdges = new MinimumPriorityQueue<UndirectedEdge>();
for (UndirectedEdge edge : graph.edgesIterator()) {
minEdges.insert(edge);
}
int numEdges = 0;
UnionFind unionFind = new UnionFind(graph.vertices());
while (!minEdges.isEmpty() && numEdges < graph.vertices() - 1) {
UndirectedEdge edge = (UndirectedEdge) minEdges.deleteMin();
int v = edge.vertexA();
int w = edge.vertexB();
if (!unionFind.connected(v, w)) {
unionFind.union(v, w);
minimumSpanningTree.enqueue(edge);
numEdges++;
weight += edge.weight();
}
}
}
