103 lines
4.7 KiB
Plaintext
103 lines
4.7 KiB
Plaintext
Advent of Code
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--- Day 14: Chocolate Charts ---
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You finally have a chance to look at all of the produce moving around.
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Chocolate, cinnamon, mint, chili peppers, nutmeg, vanilla... the Elves must
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be growing these plants to make hot chocolate! As you realize this, you hear
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a conversation in the distance. When you go to investigate, you discover two
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Elves in what appears to be a makeshift underground kitchen/laboratory.
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The Elves are trying to come up with the ultimate hot chocolate recipe;
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they're even maintaining a scoreboard which tracks the quality score (0-9)
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of each recipe.
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Only two recipes are on the board: the first recipe got a score of 3, the
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second, 7. Each of the two Elves has a current recipe: the first Elf starts
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with the first recipe, and the second Elf starts with the second recipe.
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To create new recipes, the two Elves combine their current recipes. This
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creates new recipes from the digits of the sum of the current recipes'
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scores. With the current recipes' scores of 3 and 7, their sum is 10, and so
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two new recipes would be created: the first with score 1 and the second with
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score 0. If the current recipes' scores were 2 and 3, the sum, 5, would only
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create one recipe (with a score of 5) with its single digit.
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The new recipes are added to the end of the scoreboard in the order they are
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created. So, after the first round, the scoreboard is 3, 7, 1, 0.
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After all new recipes are added to the scoreboard, each Elf picks a new
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current recipe. To do this, the Elf steps forward through the scoreboard a
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number of recipes equal to 1 plus the score of their current recipe. So,
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after the first round, the first Elf moves forward 1 + 3 = 4 times, while
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the second Elf moves forward 1 + 7 = 8 times. If they run out of recipes,
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they loop back around to the beginning. After the first round, both Elves
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happen to loop around until they land on the same recipe that they had in
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the beginning; in general, they will move to different recipes.
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Drawing the first Elf as parentheses and the second Elf as square brackets,
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they continue this process:
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(3)[7] (3)[7] 1 0 3 7 1 [0](1) 0 3 7 1 0 [1] 0 (1) (3) 7 1 0 1 0 [1]
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2 3 7 1 0 (1) 0 1 2 [4] 3 7 1 [0] 1 0 (1) 2 4 5 3 7 1 0 [1] 0 1
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2 (4) 5 1 3 (7) 1 0 1 0 [1] 2 4 5 1 5 3 7 1 0 1 0 1 2 [4](5) 1
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5 8 3 (7) 1 0 1 0 1 2 4 5 1 5 8 [9] 3 7 1 0 1 0 1 [2] 4 (5) 1
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5 8 9 1 6 3 7 1 0 1 0 1 2 4 5 [1] 5 8 9 1 (6) 7 3 7 1 0 (1)
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0 1 2 4 5 1 5 [8] 9 1 6 7 7 3 7 [1] 0 1 0 (1) 2 4 5 1 5 8 9
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1 6 7 7 9 3 7 1 0 [1] 0 1 2 (4) 5 1 5 8 9 1 6 7 7 9 2
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The Elves think their skill will improve after making a few recipes (your
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puzzle input). However, that could take ages; you can speed this up
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considerably by identifying the scores of the ten recipes after that. For
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example:
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• If the Elves think their skill will improve after making 9 recipes, the
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scores of the ten recipes after the first nine on the scoreboard would be
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5158916779 (highlighted in the last line of the diagram). • After 5
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recipes, the scores of the next ten would be 0124515891. • After 18
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recipes, the scores of the next ten would be 9251071085. • After 2018
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recipes, the scores of the next ten would be 5941429882.
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What are the scores of the ten recipes immediately after the number of
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recipes in your puzzle input?
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Your puzzle answer was 1776718175.
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--- Part Two ---
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As it turns out, you got the Elves' plan backwards. They actually want to
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know how many recipes appear on the scoreboard to the left of the first
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recipes whose scores are the digits from your puzzle input.
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• 51589 first appears after 9 recipes. • 01245 first appears after 5
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recipes. • 92510 first appears after 18 recipes. • 59414 first appears
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after 2018 recipes.
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How many recipes appear on the scoreboard to the left of the score sequence
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in your puzzle input?
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Your puzzle answer was 20220949.
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Both parts of this puzzle are complete! They provide two gold stars: **
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Your puzzle input was 290431.
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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://adventofcode.com/2018
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