public class Seat
{
    /** Returns true if this seat has been sold */
    public boolean isSold()
    { /* implementation not shown */ }

    // There may be instance variables, constructors,
    // and methods that are not shown.
}

public class Theater
{
    /** The seating chart; rectangular, with at least one row */
    private Seat[][] seats;

    /** Returns the index of the row closest to the stage that
     *  has at least groupSize unsold seats next to each other
     *  in the same row, or -1 if no row does.
     *  Precondition: groupSize >= 1
     */
    public int findRow(int groupSize)
    { /* to be implemented */ }

    // There may be instance variables, constructors,
    // and methods that are not shown.
}