Ruby was the language of choice because of it opens source libraries(or gems), its community, and lastly because of the present developer's strength with the language. Then, in order to quickly build a Rack based api the Sinatra framework was chosen for its quick setup and simplicity. The design mainly aimed at solving the problem at hand, but to also keep future extensibility and change in mind.
Since this is an HTTP API, JSON was chosen as the request/response format, mainly to help ensure uniformity and standardization as the application grows.
In order to find the minimum number of Fleet Engineers (FE) needed: First, we find the district where the Fleet Manager's (FM) presence would reduce the need for FEs the most. To that district we assign the FM. Then, we calculate how many FEs are still necessary to perform maintenance on the remaining scooters.
Given more time, it would be worthwhile to add tests to this application. Further, given more requirements and information on the product, some more thought will have to be put into the structure of the application as it grows.
Using JSON as the request/response format implied slight changes to the formatting of the inputs in the challenge documentation, like adding quotes to the keys.
To run, first do:
bundle install
Then, launch app (e.g. on port 4567):
rackup -p 4567
The endpoint:
post '/scooters'
and a request with the body:
{ "scooters": [15, 10],
"C": 12,
"P": 5 }gets the response:
{ "fleet_engineers" : 3 }