brettwgreen / ltl_assignment

Truck shipping distribution code challenge (ltl_assignment)

Setup and Run:

Ruby 2.6.5

I use rvm... so rvm install 2.6.5 if you don't already have it

Then simply:

bundle install
rspec --format doc

General notes

• RSpec used as testing framework
• Truck and shipping samples loaded from YAML files
• Just passing hashes around for data
• Added awesome_print gem... there's an ap result in the main test that will print out the truck distributions that is commented out, but was using that to visualize what my algorithm attempts were spitting out.

Algorithm notes

• Started with pretty basic thing to sort all trucks in descending order of capacity, then all shipments in descending order as well
• Then just walked all trucks and put the biggest shipment in each truck that would fit
• Was not sure what was acheivable, so started with 'hey can I fill each truck to 90%'?
• Well, that did not work to 90%, but was able to acheive 75% with that and at least I had something I could iterate/experiment with
• Tried one more algorithm change to 'find the tightest fit given a truck with available capacity and a set of shipments'
• That seemed like how I might pack a truck when I'm moving or packing for vacation. Don't think it really moved the needle, but seemed abstractly like a better algorithm

Future improvements

• I think the change that would move the needle was to take the set of trucks with available capacity and the remaining shipments and find the 'tighest fit' in those collections, add that shipment to the truck, rinse and repeat. I started refactoring that, but thought I had spent enough time and that was a fair amount of change to my structure.
• I did do a cursory search when done and landed on some 'packing algorithms' that seemed to at least rudimentally confirm my point above (I kinda wanted to see what I could come up with before looking around), although I'm sure it can get pretty sophisticated.
• Add a lot more tests and assertions at a more granular level... obviously more test scenarios as well.
  • Test the find_shipment_that_fits method directly since it's the core of the operation.
  • Really should have an assertion in there that shipments don't appear in more than one truck.
• Obviously, using real classes Truck, Shipment and TruckDistrubution would be a lot better than passing hashes around.