AdventOfCode/day12/README

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Day 12 Notes
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| Part 1 |
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$ elixir day12part1.exs
923
Thoughts:
This was pretty fun :-)
I spent ages fixing stupid typos and didn't realise I'd forgotten to take account for the fact that
a rotation command could contain more than 90 degrees. I submitted so many wrong answers I had to
wait 3 minutes to submit the correct one... oops.
Decided to store the direction as an {x, y} vector, and handle rotations as just flipping the
values as required. Use recursion to do it repetedly for rotations of more than 90 degrees.
NSEW operations are just simply adjusting the coordinates as required.
For F, apply the vector to the boat's current position.
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| Part 2 |
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$ elixir day12part2.exs
24769
Thoughts:
Interesting. The fact that the waypoint moves when the boat moves makes this part very simple.
Thankfully I stored the rotation as a vector in part 1, which is basically the waypoint
fixed at a distance of 1. So for this part, can just adjust the NSEW commands to move the
waypoint/vector instead of the boat.
The rest of the commands are the same.
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| Overall Thoughts |
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I liked this one. Figuring out how to do the rotation efficiently probably took the most time,
but I'm pretty happy with the results 😊