It's also a game/challenge, and these are all good opportunities to learn different methods to do things. And in a production environment might not have the option to change language but can still make the code run faster where and how we can.

If I was worrying about the cost of operations like division, I wouldn't be using Python.

If you know what format the temperature is coming in already, you can just check it against the type to convert to. There is no such thing as "both". It is one or the other. Whenever you use both, the calculation for the same type of temperature will always be wrong (input fahrenheit, convert with "both", output fahrenheit will be different because it was treated as celcius).

EDIT: Ok, I see - it is tested upon and expected to work that way. Still a dumb idea. One will always be wrong, why bother.

You are right. I couldn't think of a way to make the previous any faster or more concise :-(

Never put links directly to /train pages.

O(n^2) is a time complxity (e.g., quadratic time). Recursive calculations of Fibonacci numbers use O(n^2) time complexity.