Using php5.2 and MySQL 4.1.22
I(ve come across something that, at first, appeared simple but has since evaded me in regards to a simple, clean solution.
We have pre-defined "packages" of product. Package 1 may have products A, B and C in it. Package 2 may have A, C, D and G in it, etc. The packages range in size from 3 to 5 products.
Now, a customer can pick any 10 products available and make a "custom" package. Since we already have certain predefined packages, we(d like to build the custom package with smaller existing packages (for shipping ease) where possible.
So, for instance, a customer selects to create a (custom package( of products A, B, C, D, E and F. We already have a predefined package that contains A, B and C called Foo. So, the order would then be Foo, D, E and F.
The catch is in having the least amount of individual items, followed by the least amount of packages. For instance:
Custom Package: A, B, C, D, E, F, G, H, I, J.
Predefined Package (1): A, B, C, D, E
Predefined Package (2): A, B, C
Predefined Package (3): D, E, F
If I simply take the largest match, then I have 1 (5pc) package and 5 individual items. Neither Package (2) nor (3) can be built with the remaining items.
If I look deeper, I find that by not building package (1) I can instead build package (2) and package (3). Which means I have 2 packages and 4 individual items (a better choice in this buisiness rule).
As I(m using MySQL, I(m under the restraint of only having one layer of sub select available (to my knowledge). So this sort will need to be performed in php. I(ve looked at using array_intersect() to determine matches, but every way I(ve found grows exponentially in regards to processing as the number of predefined packages grows linearly.
I ran this by a couple other coder friends and again, while it seemed like there should be an easy answer we all found that it wasn(t as simple as it seems. So, I thought I(d post it here as a nice noodle stretcher. Thanks much in advance for your time!
posted date: 2009-04-09 13:59:00