113 lines
4.8 KiB
Plaintext
113 lines
4.8 KiB
Plaintext
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Advent of Code
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--- Day 23: Experimental Emergency Teleportation ---
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Using your torch to search the darkness of the rocky cavern, you finally
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locate the man's friend: a small reindeer.
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You're not sure how it got so far in this cave. It looks sick - too sick to
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walk - and too heavy for you to carry all the way back. Sleighs won't be
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invented for another 1500 years, of course.
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The only option is experimental emergency teleportation.
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You hit the "experimental emergency teleportation" button on the device and
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push I accept the risk on no fewer than 18 different warning messages.
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Immediately, the device deploys hundreds of tiny nanobots which fly around
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the cavern, apparently assembling themselves into a very specific formation.
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The device lists the X,Y,Z position (pos) for each nanobot as well as its
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signal radius (r) on its tiny screen (your puzzle input).
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Each nanobot can transmit signals to any integer coordinate which is a
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distance away from it less than or equal to its signal radius (as measured
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by Manhattan distance). Coordinates a distance away of less than or equal to
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a nanobot's signal radius are said to be in range of that nanobot.
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Before you start the teleportation process, you should determine which
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nanobot is the strongest (that is, which has the largest signal radius) and
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then, for that nanobot, the total number of nanobots that are in range of
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it, including itself.
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For example, given the following nanobots:
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pos=<0,0,0>, r=4 pos=<1,0,0>, r=1 pos=<4,0,0>, r=3 pos=<0,2,0>, r=1
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pos=<0,5,0>, r=3 pos=<0,0,3>, r=1 pos=<1,1,1>, r=1 pos=<1,1,2>, r=1
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pos=<1,3,1>, r=1
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The strongest nanobot is the first one (position 0,0,0) because its signal
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radius, 4 is the largest. Using that nanobot's location and signal radius,
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the following nanobots are in or out of range:
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• The nanobot at 0,0,0 is distance 0 away, and so it is in range. • The
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nanobot at 1,0,0 is distance 1 away, and so it is in range. • The nanobot
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at 4,0,0 is distance 4 away, and so it is in range. • The nanobot at 0,2,0
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is distance 2 away, and so it is in range. • The nanobot at 0,5,0 is
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distance 5 away, and so it is not in range. • The nanobot at 0,0,3 is
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distance 3 away, and so it is in range. • The nanobot at 1,1,1 is distance
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3 away, and so it is in range. • The nanobot at 1,1,2 is distance 4 away,
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and so it is in range. • The nanobot at 1,3,1 is distance 5 away, and so
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it is not in range.
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In this example, in total, 7 nanobots are in range of the nanobot with the
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largest signal radius.
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Find the nanobot with the largest signal radius. How many nanobots are in
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range of its signals?
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Your puzzle answer was 599.
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--- Part Two ---
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Now, you just need to figure out where to position yourself so that you're
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actually teleported when the nanobots activate.
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To increase the probability of success, you need to find the coordinate
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which puts you in range of the largest number of nanobots. If there are
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multiple, choose one closest to your position (0,0,0, measured by manhattan
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distance).
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For example, given the following nanobot formation:
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pos=<10,12,12>, r=2 pos=<12,14,12>, r=2 pos=<16,12,12>, r=4 pos=<14,14,14>,
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r=6 pos=<50,50,50>, r=200 pos=<10,10,10>, r=5
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Many coordinates are in range of some of the nanobots in this formation.
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However, only the coordinate 12,12,12 is in range of the most nanobots: it
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is in range of the first five, but is not in range of the nanobot at
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10,10,10. (All other coordinates are in range of fewer than five nanobots.)
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This coordinate's distance from 0,0,0 is 36.
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Find the coordinates that are in range of the largest number of nanobots.
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What is the shortest manhattan distance between any of those points and
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0,0,0?
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Your puzzle answer was 94481130.
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Both parts of this puzzle are complete! They provide two gold stars: **
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At this point, you should return to your Advent calendar and try another
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puzzle.
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If you still want to see it, you can get your puzzle input.
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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/2018/about
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. https://adventofcode.com/2018/events
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. https://adventofcode.com/2018/settings
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. https://adventofcode.com/2018/auth/logout
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. Advent of Code Supporter
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https://adventofcode.com/2018/support
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. https://adventofcode.com/2018
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. https://adventofcode.com/2018
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. https://adventofcode.com/2018/support
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. https://adventofcode.com/2018/sponsors
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. https://adventofcode.com/2018/leaderboard
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. https://adventofcode.com/2018/stats
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. https://adventofcode.com/2018/sponsors
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. https://en.wikipedia.org/wiki/Taxicab_geometry
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. https://adventofcode.com/2018
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. https://adventofcode.com/2018/day/23/input
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