It's about 30% slower, but a lot nicer.

Calculate the power inline so we don't have to repeat the rack ID
etc every time; give in and use 1-based arrays instead of mapping
the 1-base back to 0-base.

We don't need to store values as we can figure them out from
the memory location.

Leaderboard position: 70 and 84

Somehow this got the right answer for most cases.

Leaderboard position: 124 & 365

time(1) just shows fewer decimal places than bash's time, and
I didn't notice!

Reverse the input so we can just pop entries off the end as we use
them, instead of tracking offsets horribly.

- Skip over times when nothing is going to happen
- Instead of storing time remaining and decrementing it each cycle,
  store the end time instead

This code was brought to you by insomnia.