90 lines
3.3 KiB
Org Mode
90 lines
3.3 KiB
Org Mode
** --- Day 1: Calorie Counting ---
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Santa's reindeer typically eat regular reindeer food, but they need a
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lot of [[/2018/day/25][magical energy]] to deliver presents on
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Christmas. For that, their favorite snack is a special type of /star/
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fruit that only grows deep in the jungle. The Elves have brought you on
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their annual expedition to the grove where the fruit grows.
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To supply enough magical energy, the expedition needs to retrieve a
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minimum of /fifty stars/ by December 25th. Although the Elves assure you
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that the grove has plenty of fruit, you decide to grab any fruit you see
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along the way, just in case.
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Collect stars by solving puzzles. Two puzzles will be made available on
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each day in the Advent calendar; the second puzzle is unlocked when you
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complete the first. Each puzzle grants /one star/. Good luck!
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The jungle must be too overgrown and difficult to navigate in vehicles
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or access from the air; the Elves' expedition traditionally goes on
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foot. As your boats approach land, the Elves begin taking inventory of
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their supplies. One important consideration is food - in particular, the
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number of /Calories/ each Elf is carrying (your puzzle input).
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The Elves take turns writing down the number of Calories contained by
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the various meals, snacks, rations, etc. that they've brought with them,
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one item per line. Each Elf separates their own inventory from the
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previous Elf's inventory (if any) by a blank line.
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For example, suppose the Elves finish writing their items' Calories and
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end up with the following list:
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#+begin_example
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1000
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2000
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3000
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4000
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5000
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6000
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7000
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8000
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9000
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10000
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#+end_example
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This list represents the Calories of the food carried by five Elves:
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- The first Elf is carrying food with =1000=, =2000=, and =3000=
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Calories, a total of =6000= Calories.
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- The second Elf is carrying one food item with =4000= Calories.
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- The third Elf is carrying food with =5000= and =6000= Calories, a
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total of =11000= Calories.
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- The fourth Elf is carrying food with =7000=, =8000=, and =9000=
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Calories, a total of =24000= Calories.
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- The fifth Elf is carrying one food item with =10000= Calories.
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In case the Elves get hungry and need extra snacks, they need to know
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which Elf to ask: they'd like to know how many Calories are being
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carried by the Elf carrying the /most/ Calories. In the example above,
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this is /=24000=/ (carried by the fourth Elf).
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Find the Elf carrying the most Calories. /How many total Calories is
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that Elf carrying?/
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Your puzzle answer was =66719=.
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** --- Part Two ---
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By the time you calculate the answer to the Elves' question, they've
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already realized that the Elf carrying the most Calories of food might
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eventually /run out of snacks/.
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To avoid this unacceptable situation, the Elves would instead like to
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know the total Calories carried by the /top three/ Elves carrying the
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most Calories. That way, even if one of those Elves runs out of snacks,
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they still have two backups.
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In the example above, the top three Elves are the fourth Elf (with
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=24000= Calories), then the third Elf (with =11000= Calories), then the
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fifth Elf (with =10000= Calories). The sum of the Calories carried by
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these three elves is =45000=.
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Find the top three Elves carrying the most Calories. /How many Calories
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are those Elves carrying in total?/
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Your puzzle answer was =198551=.
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Both parts of this puzzle are complete! They provide two gold stars: **
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