[C++] 最小生成树

package com.jimmysun.algorithms.chapter4_3;
import com.jimmysun.algorithms.chapter1_3.Queue;
import edu.princeton.cs.algs4.IndexMinPQ;
public class Ex22PrimMST {
private Edge[] edgeTo;
   private double[] distTo;
   private boolean[] marked;
   private IndexMinPQ<Double> pq;
   public Ex22PrimMST(EdgeWeightedGraph G) {
    edgeTo = new Edge[G.V()];
    distTo = new double[G.V()];
    marked = new boolean[G.V()];
    for (int v = 0; v < G.V(); v++) {
     distTo[v] = Double.POSITIVE_INFINITY;
    }
    pq = new IndexMinPQ<Double>(G.V());
    for (int v = 0; v < G.V(); v++) {
if (!marked[v]) {
      distTo[v] = 0.0;
      pq.insert(v, 0.0);
      while (!pq.isEmpty()) {
         visit(G, pq.delMin());
      }
     }
    }
   }
private void visit(EdgeWeightedGraph G, int v) {
    marked[v] = true;
    for (Edge e : G.adj(v)) {
int w = e.other(v);
     if (marked[w]) {
continue;
     }
if (e.weight() < distTo[w]) {
      edgeTo[w] = e;
      distTo[w] = e.weight();
      if (pq.contains(w)) {
         pq.changeKey(w, distTo[w]);
      } else {
         pq.insert(w, distTo[w]);
      }
     }
    }
   }
public Iterable<Edge> edges() {
    Queue<Edge> mst = new Queue<>();
    for (Edge edge : edgeTo) {
if (edge != null) {
      mst.enqueue(edge);
     }
    }
return mst;
   }
}