The most indian comment above

and a nested cycle

The description is bad and needs to be re-written by a native English speaker. It's very ambiguous and almost every comment is complaining about this exact problem. Here is a suggestion to put at the top:

tl;dr Return the total value of the waiting times for all customers, so that the waiting time is the least it could be.
(ie. Customer 1's wait + Customer 2's wait + Customer 3's wait...)

Simple

These are more ESL problems than math or programming problems. Really wish a native speaker would go through and make all of these less ambiguous.

Where do you see that?

Why every next coffee takes less time to make? What is going on?

Im stuck on this too, i really get more and more confuse, there aren't number that dup.

Thanks bruh

Nice solution!

ahah, good job

The blocks are wrong, not a kata issue.

Cant understand why is this False. I have only this test unexcepted. Looks True for me.

Test number 6

[[1, 2, 3, 4, 5, 6, 7, 8, 9] ,[2, 3, 4, 5, 6, 7, 8, 9, 1] ,[3, 4, 5, 6, 7, 8, 9, 1, 2] ,[4, 5, 6, 7, 8, 9, 1, 2, 3] ,[5, 6, 7, 8, 9, 1, 2, 3, 4] ,[6, 7, 8, 9, 1, 2, 3, 4, 5] ,[7, 8, 9, 1, 2, 3, 4, 5, 6] ,[8, 9, 1, 2, 3, 4, 5, 6, 7] ,[9, 1, 2, 3, 4, 5, 6, 7, 8]]), False);