You solved the problem, but missed the point of the kata that was to use a Window Function

I would add that adding prices has no practical sense.

Efficient...

This is the ony answer I´ve seen that deals with the input restrictions. Good job.

Because there could be people in the people table that don't have a match on the job table.

It is exactly the opposite, 0 is falsy, and all other numbers are truthy.

maybe because you're using a1 + a1 instead of a1 + a2

Interesting kata.

But... I've had some issues trying to solve it using R. The console won't let me install nor does it acknowledge the series package, even though this package was released with R's version 2.7 and the platform uses 3.4.1. Even though I could load the stringr package, there are some functions I could use and others that I couldn't.

Maybe the kata is meant to be solved using base R, but would appreciate it a lot if someone from Codewars could look into it.