import java.util.List;

public interface State
{

/*
    This is an interface that describes the properties that
    states of a state space must have in order for a
    minimax search algorithm
    to be able to find a solution.

    There are three methods in this interface.

    The methods actually define the state space,
    given an appropriate definition of a state class
    (that implements this interface),
    and an appropriate constructor for this class.


*/



/**
    Determines whether a goal state
    (that is, a terminal state) reprensents a win
    for the <em>current</em> player.
    If invoked for a nongoal state, this method returns
    an unpredictable value.
    @return <code>true</code> iff the state represents
     a win for the current player
*/


boolean findValue();

/**
 
    This method corresponds to the <code>Goal-Test</code> function of 
    Russell and Norvig.
    @return <code>true</code> iff the state represents a goal state
    (also known as a terminal state).
*/

boolean isGoal();


/**
    This method corresponds to the <code>Expand</code> function
    of Russell and Norvig.
    @return a <code>List</code> of the successors of the given state 
    in the state space.
*/

List<State> findSuccessors();


}