// This code is from "Algorithms in Java, Third Edition,"
// by Robert Sedgewick, Addison-Wesley, 2003.

// See p. 231

class Edge //implements Item // ADT interface
{ // implementations and private members hidden
  private int tail;
  private int head;
  private double weight;

  Edge(int tail, int head, double weight)
  {
    this.tail=tail;
    this.head=head;
    this.weight=weight;
  }

  public int v()
  {
    return tail;
  }

  public int w()
  {
    return head;
  }

  double wt()
  {
    return weight;
  }

  boolean from(int x)
  {
    return x==v();
  }

  int other(int x)
  {
    if (from(x))
      return w();
    return v();
  }

  public boolean less(Edge x)
  {
    if (this.tail<x.v())
      return true;
    if (this.tail>x.v())
      return false;
    return this.head<x.w();
  }

  public String toString()
  {
    return "Edge " + tail + "->" + head + " wt " + weight;
  }
}