BreadthFirstSearch.java

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package aud.example.graph;
 
import aud.Queue;
 
public class BreadthFirstSearch extends Traversal {
 
  public BreadthFirstSearch(MyGraph g) {
    super(g);
  }
 
  @Override public String name() { return "BFS"; };
 
  @Override public void start(MyNode s0) {
    initialize(); // reset all node attributes
 
    int count=0;
    Queue<MyNode> open=new Queue<MyNode>();
    s0.ord=count++;
    s0.d=0.0;
 
    showMark(s0);
 
    open.enqueue(s0);
 
    while (!open.is_empty()) {
      if (verbose>0)
        System.out.println("open="+open.toString());
 
      MyNode s=open.dequeue();
 
      showVisit(s);
 
      for (MyEdge e : g_.getOutEdges(s)) {
 
        if (verbose>0)
          System.err.println(e);
 
        MyNode t=(MyNode) e.destination();
        if (t==s)
            t=(MyNode) e.source(); // undirected graph
 
        if (t.ord<0) { // <=> not marked
          t.ord=count++;
          t.p=s;
          t.d=s.d+(e.hasWeight() ? e.getWeight() : 1.0);
 
          showMark(t);
 
          open.enqueue(t);
        }
      }
    }
  }
 
}