117 lines
4.3 KiB
Plaintext
117 lines
4.3 KiB
Plaintext
[1]Advent of Code
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br0xen [7](AoC++) 12*
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--- Day 6: Trash Compactor ---
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After helping the Elves in the kitchen, you were taking a break and
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helping them re-enact a movie scene when you over-enthusiastically jumped
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into the garbage chute!
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A brief fall later, you find yourself in a garbage smasher. Unfortunately,
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the door's been magnetically sealed.
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As you try to find a way out, you are approached by a family of
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cephalopods! They're pretty sure they can get the door open, but it will
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take some time. While you wait, they're curious if you can help the
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youngest cephalopod with her [16]math homework.
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Cephalopod math doesn't look that different from normal math. The math
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worksheet (your puzzle input) consists of a list of problems; each problem
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has a group of numbers that need to be either added (+) or multiplied (*)
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together.
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However, the problems are arranged a little strangely; they seem to be
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presented next to each other in a very long horizontal list. For example:
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123 328 51 64
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45 64 387 23
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6 98 215 314
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* + * +
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Each problem's numbers are arranged vertically; at the bottom of the
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problem is the symbol for the operation that needs to be performed.
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Problems are separated by a full column of only spaces. The left/right
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alignment of numbers within each problem can be ignored.
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So, this worksheet contains four problems:
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• 123 * 45 * 6 = 33210
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• 328 + 64 + 98 = 490
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• 51 * 387 * 215 = 4243455
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• 64 + 23 + 314 = 401
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To check their work, cephalopod students are given the grand total of
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adding together all of the answers to the individual problems. In this
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worksheet, the grand total is 33210 + 490 + 4243455 + 401 = 4277556.
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Of course, the actual worksheet is much wider. You'll need to make sure to
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unroll it completely so that you can read the problems clearly.
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Solve the problems on the math worksheet. What is the grand total found by
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adding together all of the answers to the individual problems?
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Your puzzle answer was 6295830249262.
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--- Part Two ---
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The big cephalopods come back to check on how things are going. When they
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see that your grand total doesn't match the one expected by the worksheet,
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they realize they forgot to explain how to read cephalopod math.
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Cephalopod math is written right-to-left in columns. Each number is given
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in its own column, with the most significant digit at the top and the
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least significant digit at the bottom. (Problems are still separated with
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a column consisting only of spaces, and the symbol at the bottom of the
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problem is still the operator to use.)
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Here's the example worksheet again:
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123 328 51 64
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45 64 387 23
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6 98 215 314
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* + * +
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Reading the problems right-to-left one column at a time, the problems are
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now quite different:
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• The rightmost problem is 4 + 431 + 623 = 1058
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• The second problem from the right is 175 * 581 * 32 = 3253600
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• The third problem from the right is 8 + 248 + 369 = 625
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• Finally, the leftmost problem is 356 * 24 * 1 = 8544
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Now, the grand total is 1058 + 3253600 + 625 + 8544 = 3263827.
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Solve the problems on the math worksheet again. What is the grand total
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found by adding together all of the answers to the individual problems?
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Your puzzle answer was 9194682052782.
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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 [17]return to your Advent calendar and try
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another puzzle.
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If you still want to see it, you can [18]get your puzzle input.
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References
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Visible links
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1. https://adventofcode.com/
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2. https://adventofcode.com/2025/about
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3. https://adventofcode.com/2025/events
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4. https://adventofcode.com/2025/shop
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5. https://adventofcode.com/2025/settings
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6. https://adventofcode.com/2025/auth/logout
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7. Advent of Code Supporter
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https://adventofcode.com/2025/support
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8. https://adventofcode.com/2025
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9. https://adventofcode.com/2025
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10. https://adventofcode.com/2025/support
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11. https://adventofcode.com/2025/sponsors
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12. https://adventofcode.com/2025/leaderboard/private
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13. https://adventofcode.com/2025/stats
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14. https://adventofcode.com/2025/sponsors
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16. https://adventofcode.com/2021/day/18
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17. https://adventofcode.com/2025
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18. https://adventofcode.com/2025/day/6/input
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