import java.util.List;
import java.util.LinkedList;

/*
    This class represents a game that begins with a pile 
      of sticks of a given size, and where players alternate 
      taking exactly one or two sticks from the pile.  The 
      player who takes last stick, thus leaving an empty pile, 
      is the winner.
 */


public class OneOrTwoState implements State 
{

  private int remainder;  // the number of sticks remaining
  
  
  /*
      A constructor
      @param n the number of sticks initially in the pile
   */
  
  public OneOrTwoState(int n)       {
    remainder = n;                  }
  
  
  // If there is at least one stick remaining,
  //   a successor is created that corresponds
  //   to the current player's taking exactly one stick
  // If there are at least two sticks remaining,
  //   a successor is created that corresponds
  //   to the current player's taking exactly two sticks
  
  public List<State> findSuccessors()   {
    LinkedList<State> successors
      = new LinkedList<State>();
    if (remainder>=1)
      successors.add(
        new OneOrTwoState(remainder-1));	
    if (remainder>=2)
      successors.add(
        new OneOrTwoState(remainder-2));	
    return successors;                   }
  
  
  
  // a state is a goal state iff there are
  //   no sticks remaining
  
  public boolean isGoal()           {
    return remainder==0;            }
  
  
  // if there are no elements left, 
  //   the current player loses
  
  public boolean findValue()        {
    return false;                   }
  
	
  /**
      the printed representation of a state
        just says how many sticks remain
  */ 
  
  public String toString()                {
    return Integer.toString(remainder);   }
  
	
}