[jfengel]

I think 150 lines of python is rather a lot. That would take at least an hour to write, and can run up to a few days (depending on complexity and familiarity with the task).

[emil-lp]

You should do some competitive coding.

Many, if not most, medium to hard problems require at least 100–150 lines of code. With experience, you can write it, bugfree, in 15 minutes.

It's about thinking ahead and experience.