private readonly Collections.Queue <EdgeW> _mst = new Collections.Queue <EdgeW>(); // edges in MST /// <summary> /// Compute a minimum spanning tree (or forest) of an edge-weighted graph. /// </summary> /// <param name="g">g the edge-weighted graph</param> public KruskalMST(EdgeWeightedGraph g) { // more efficient to build heap by passing array of edges var pq = new MinPQ <EdgeW>(); foreach (var e in g.Edges()) { pq.Insert(e); } // run greedy algorithm var uf = new UF(g.V); while (!pq.IsEmpty() && _mst.Size() < g.V - 1) { var e = pq.DelMin(); var v = e.Either(); var w = e.Other(v); if (!uf.Connected(v, w)) { // v-w does not create a cycle uf.Union(v, w); // merge v and w components _mst.Enqueue(e); // add edge e to mst _weight += e.Weight; } } // check optimality conditions //assert check(G); }