private void prim(int s, StringBuilder sb) { distTo[s] = 0; pq.insert(s, distTo[s]); while (!pq.isEmpty()) { int v = pq.delMin(); if (v != s) { Route r = edgeTo[v]; String str = String.format("%s, %s : %d\n", r.fst(), r.snd(), r.distance()); sb.append(str); } scan(v); } }