From: Logesh Pillay <logesh@...>
Date: 2006-06-16T03:34:07+09:00
Subject: Newbie program

I discovered Ruby this week.  I was amazed at how easy it was to program 
in it without a book or any  real manual.
I've written the following program.  It looks too much like the python 
original to be good idiomatic ruby.  I'd appreciate suggestions how to 
improve it.
Thanks.
Logesh
#returns the ways one can place n queens on a
#chessboard of size n*n so that no queen is attacking another
#Ruby 1.8.3;  15 June 2006
def nqueens
  $n = 8
  $board = [nil] * ($n+1)
  def choose(k)
    if k > $n
      print $board, "\n"
    else
      for i in 1..$n
        $board[k] = i
        choose(k + 1) if k == 1 or stillgood(k)
      end
    end
  end
  def stillgood(k)
    for i in 1...k
      return false if ($board[k] == $board[i]) or
        (k-i == ($board[k] - $board[i]).abs)
    end
    return true
  end
end
nqueens.choose(1)