COM 1204 Assignment #6.
Due: Wednesday, 29 May 2002

Working individually, you will design and implement a Java
program that solves the following problem:  Given a positive
integer n, what is the smallest number of chess queens that
can be placed on an n by n chessboard in such a way that no
two queens can attack another, but every square of the board
is either occupied by a queen or under attack by at least
one queen?  In addition, your program will generate a display
that shows how the minimal number of queens can be placed to
achieve this objective.

Your program should be capable of working for any positive
integral value of n, up to and including the largest integer
that can be represented as a Java int.  Your program should
solve the problem quickly when n is a small integer such as
8; this implies, for example, that your program cannot simply
generate all 2^n placements of queens on an n by n chessboard
and test these placements to see which ones solve the problem.

Collaboration between students is forbidden on this assignment.
You are responsible for keeping your code hidden from all other
students.  Your grade will be determined by these factors:

    how well you hide your code from others
    how well you follow instructions for submitting your code
    correctness of your program
    efficiency of your program
    readability and clarity of your program
        (e.g. indentation, formatting, comments, simplicity)

Turn in your work on this assignment before 4 pm on the due
date by sending each of the Java files in your program in a
separate electronic mail to

    will@ccs.neu.edu

The subject of each message must be

    COM 1204 assignment #6: 

followed by a space and the name of the file whose contents
are the body of that message.  For example, the message that
submits your QueenSolver.java file should have

    COM 1204 assignment #6: QueenSolver.java

as its subject.

The body of each email must consist of nothing but the Java
code for the file named in the subject.  That file must begin
with a Java block comment that lists

    1.  Your name.
    2.  Any remarks that you wish to make to the instructor.

Late assignments may be discounted, and very late assignments
may be discarded.

Your email must be sent as plain text, with no MIME or HTML
encoding, and must not include any signature lines or other
stray characters that would prevent your code from compiling
and running.  Furthermore your code should follow the other
guidelines announced in class.

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The instructor is providing the textbook's code for the 8
queens problem in /course/com1204/.www/will/Assignments/A6.
This code is being provided to show you one way to draw a
graphics window that displays queens on a chessboard.

Your program must contain a file named QueenSolver.java
that declares a public class QueenSolver that contains a
public static void main (String) method.  Your program
will be called with one command-line argument n, an integer,
as in

    % java QueenSolver 8

Your program must print, to System.out, the minimum number
of queens required to occupy or to attack every square of
an n by n chessboard, without any pair of queens attacking
each other.  Your program must then show how to accomplish
that goal using that many queens on an n by n chessboard.
This display must work for all n < 10, but the display part
of your program is not required to work well for large
values of n.