"We need to fly home as cheaply as possible so that more money is left for gifts. Aunt Lidia asked for different kinds of cheeses, and Vasia wanted a new toy car. I’ve been looking at the schedule for quite a while and I’m starting to think that some planes are flying in vain".
As the input you get the flight schedule as an list, each element of which is the price of a direct flight between 2 cities (list of 3 elements...
CheckiO Extensions allow you to use local files to solve missions. More info in a blog post.
In order to install CheckiO client you'll need installed Python (version at least 3.8)
Install CheckiO Client first:
pip3 install checkio_client
Configure your tool
checkio --domain=py config --key=
Sync solutions into your local folder
(in beta testing) Launch local server so your browser can use it and sync solution between local file end extension on the fly. (doesn't work for safari)
checkio serv -d
Alternatevly, you can install Chrome extension or FF addon
checkio install-plugin --ff
checkio install-plugin --chromium