89 lines
3.4 KiB
Plaintext
89 lines
3.4 KiB
Plaintext
Advent of Code
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--- Day 13: Knights of the Dinner Table ---
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In years past, the holiday feast with your family hasn't gone so well. Not
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everyone gets along! This year, you resolve, will be different. You're going
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to find the optimal seating arrangement and avoid all those awkward
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conversations.
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You start by writing up a list of everyone invited and the amount their
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happiness would increase or decrease if they were to find themselves sitting
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next to each other person. You have a circular table that will be just big
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enough to fit everyone comfortably, and so each person will have exactly two
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neighbors.
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For example, suppose you have only four attendees planned, and you calculate
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their potential happiness as follows:
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Alice would gain 54 happiness units by sitting next to Bob.
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Alice would lose 79 happiness units by sitting next to Carol.
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Alice would lose 2 happiness units by sitting next to David.
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Bob would gain 83 happiness units by sitting next to Alice.
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Bob would lose 7 happiness units by sitting next to Carol.
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Bob would lose 63 happiness units by sitting next to David.
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Carol would lose 62 happiness units by sitting next to Alice.
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Carol would gain 60 happiness units by sitting next to Bob.
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Carol would gain 55 happiness units by sitting next to David.
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David would gain 46 happiness units by sitting next to Alice.
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David would lose 7 happiness units by sitting next to Bob.
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David would gain 41 happiness units by sitting next to Carol.
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Then, if you seat Alice next to David, Alice would lose 2 happiness units
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(because David talks so much), but David would gain 46 happiness units
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(because Alice is such a good listener), for a total change of 44.
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If you continue around the table, you could then seat Bob next to Alice (Bob
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gains 83, Alice gains 54). Finally, seat Carol, who sits next to Bob (Carol
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gains 60, Bob loses 7) and David (Carol gains 55, David gains 41). The
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arrangement looks like this:
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+41 +46
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+55 David -2
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Carol Alice
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+60 Bob +54
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-7 +83
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After trying every other seating arrangement in this hypothetical scenario,
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you find that this one is the most optimal, with a total change in happiness
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of 330.
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What is the total change in happiness for the optimal seating arrangement of
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the actual guest list?
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Your puzzle answer was 733.
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--- Part Two ---
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In all the commotion, you realize that you forgot to seat yourself. At this
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point, you're pretty apathetic toward the whole thing, and your happiness
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wouldn't really go up or down regardless of who you sit next to. You assume
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everyone else would be just as ambivalent about sitting next to you, too.
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So, add yourself to the list, and give all happiness relationships that
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involve you a score of 0.
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What is the total change in happiness for the optimal seating arrangement
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that actually includes yourself?
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Your puzzle answer was 725.
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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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. http://adventofcode.com/
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. http://adventofcode.com/about
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. http://adventofcode.com/stats
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. http://adventofcode.com/leaderboard
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. http://adventofcode.com/settings
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. http://adventofcode.com/auth/logout
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. http://adventofcode.com/
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. http://adventofcode.com/day/13/input
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