The three rules of Ruby Quiz:

1.  Please do not post any solutions or spoiler discussion for this quiz until
48 hours have passed from the time on this message.

2.  Support Ruby Quiz by submitting ideas as often as you can:

http://www.rubyquiz.com/

3.  Enjoy!

Suggestion:  A [QUIZ] in the subject of emails about the problem helps everyone
on Ruby Talk follow the discussion.  Please reply to the original quiz message,
if you can.

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

by Harlan

Given an array of integers, find the sub-array with maximum sum.  For example:

	array:              [-1, 2, 5, -1, 3, -2, 1]
	maximum sub-array:  [2, 5, -1, 3]

Extra Credit:
 
Given a matrix of integers, find the rectangle with maximum sum.