94 lines
3.2 KiB
Plaintext
94 lines
3.2 KiB
Plaintext
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Advent of Code
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br0xen (AoC++) 35*
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--- Day 18: Boiling Boulders ---
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You and the elephants finally reach fresh air. You've emerged near the
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base of a large volcano that seems to be actively erupting! Fortunately,
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the lava seems to be flowing away from you and toward the ocean.
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Bits of lava are still being ejected toward you, so you're sheltering in
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the cavern exit a little longer. Outside the cave, you can see the lava
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landing in a pond and hear it loudly hissing as it solidifies.
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Depending on the specific compounds in the lava and speed at which it
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cools, it might be forming obsidian! The cooling rate should be based on
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the surface area of the lava droplets, so you take a quick scan of a
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droplet as it flies past you (your puzzle input).
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Because of how quickly the lava is moving, the scan isn't very good; its
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resolution is quite low and, as a result, it approximates the shape of the
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lava droplet with 1x1x1 cubes on a 3D grid, each given as its x,y,z
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position.
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To approximate the surface area, count the number of sides of each cube
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that are not immediately connected to another cube. So, if your scan were
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only two adjacent cubes like 1,1,1 and 2,1,1, each cube would have a
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single side covered and five sides exposed, a total surface area of 10
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sides.
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Here's a larger example:
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2,2,2
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1,2,2
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3,2,2
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2,1,2
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2,3,2
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2,2,1
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2,2,3
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2,2,4
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2,2,6
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1,2,5
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3,2,5
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2,1,5
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2,3,5
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In the above example, after counting up all the sides that aren't
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connected to another cube, the total surface area is 64.
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What is the surface area of your scanned lava droplet?
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Your puzzle answer was 4548.
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--- Part Two ---
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Something seems off about your calculation. The cooling rate depends on
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exterior surface area, but your calculation also included the surface area
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of air pockets trapped in the lava droplet.
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Instead, consider only cube sides that could be reached by the water and
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steam as the lava droplet tumbles into the pond. The steam will expand to
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reach as much as possible, completely displacing any air on the outside of
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the lava droplet but never expanding diagonally.
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In the larger example above, exactly one cube of air is trapped within the
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lava droplet (at 2,2,5), so the exterior surface area of the lava droplet
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is 58.
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What is the exterior surface area of your scanned lava droplet?
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Your puzzle answer was 2588.
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Both parts of this puzzle are complete! They provide two gold stars: **
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References
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Visible links
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. https://adventofcode.com/
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. https://adventofcode.com/2022/about
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. https://adventofcode.com/2022/events
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. https://adventofcode.com/2022/settings
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. https://adventofcode.com/2022/auth/logout
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. Advent of Code Supporter
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https://adventofcode.com/2022/support
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. https://adventofcode.com/2022
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. https://adventofcode.com/2022
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. https://adventofcode.com/2022/support
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. https://adventofcode.com/2022/sponsors
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. https://adventofcode.com/2022/leaderboard
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. https://adventofcode.com/2022/stats
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. https://adventofcode.com/2022/sponsors
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. https://en.wikipedia.org/wiki/Obsidian
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. https://adventofcode.com/2022
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. https://adventofcode.com/2022/day/18/input
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