/** Source code example for "A Practical Introduction to Data
    Structures and Algorithm Analysis, 3rd Edition (Java)" 
    by Clifford A. Shaffer
    Copyright 2008-2011 by Clifford A. Shaffer
*/

/** Graph ADT */
public interface Graph {         // Graph class ADT

  /** Initialize the graph
      @param n The number of vertices */
  public void Init(int n);

  /** @return The number of vertices */
  public int n();

  /** @return The current number of edges */
  public int e();

  /** @return v's first neighbor */
  public int first(int v);

 /** @return v's next neighbor after w */
  public int next(int v, int w);

  /** Set the weight for an edge
      @param i,j The vertices
      @param wght Edge weight */
  public void setEdge(int i, int j, int wght);

  /** Delete an edge
      @param i,j The vertices */
  public void delEdge(int i, int j);

  /** Determine if an edge is in the graph
      @param i,j The vertices
      @return true if edge i,j has non-zero weight */
  public boolean isEdge(int i, int j);


  /** @return The weight of edge i,j, or zero
      @param i,j The vertices */
  public int weight(int i, int j);

  /** Set the mark value for a vertex
      @param v The vertex
      @param val The value to set */
  public void setMark(int v, int val);

  /** Get the mark value for a vertex
      @param v The vertex
      @return The value of the mark */
  public int getMark(int v);
}