PROBLEM:
Assume you have an array of unique integers.  Write a function that will return combination of elements that add up to 7.
example: $array=array(1, 5, 4, 8, -1, 3);

I want a function that will give me 4 and 3, and 8 and -1. (it is right?)
 
For the purposes of this exercise, you can code it as if this is the actual array, 
but the function should be able to accept any array of unknown length and still process correctly.

SOLUTION:
This is a modification of the knapsack problem

URL:
The most common version is available at:
http://skygate.pl/projects/subset/

It is still BETA.