204 lines
6.3 KiB
Plaintext
204 lines
6.3 KiB
Plaintext
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[1]Advent of Code
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• [2][About]
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• [3][Events]
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• [4][Shop]
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• [5][Settings]
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• [6][Log Out]
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br0xen [7](AoC++) 28*
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$year=[8]2023;
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• [9][Calendar]
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• [10][AoC++]
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• [11][Sponsors]
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• [12][Leaderboard]
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• [13][Stats]
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Our [14]sponsors help make Advent of Code possible:
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[15]Jane Street - Will our next great idea come from you? We hire smart,
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humble people who love to solve problems, build systems, and test
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theories. Our success is driven by our people and we never stop improving.
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--- Day 14: Parabolic Reflector Dish ---
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You reach the place where all of the mirrors were pointing: a massive
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[16]parabolic reflector dish attached to the side of another large
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mountain.
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The dish is made up of many small mirrors, but while the mirrors
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themselves are roughly in the shape of a parabolic reflector dish, each
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individual mirror seems to be pointing in slightly the wrong direction. If
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the dish is meant to focus light, all it's doing right now is sending it
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in a vague direction.
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This system must be what provides the energy for the lava! If you focus
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the reflector dish, maybe you can go where it's pointing and use the light
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to fix the lava production.
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Upon closer inspection, the individual mirrors each appear to be connected
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via an elaborate system of ropes and pulleys to a large metal platform
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below the dish. The platform is covered in large rocks of various shapes.
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Depending on their position, the weight of the rocks deforms the platform,
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and the shape of the platform controls which ropes move and ultimately the
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focus of the dish.
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In short: if you move the rocks, you can focus the dish. The platform even
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has a control panel on the side that lets you tilt it in one of four
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directions! The rounded rocks (O) will roll when the platform is tilted,
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while the cube-shaped rocks (#) will stay in place. You note the positions
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of all of the empty spaces (.) and rocks (your puzzle input). For example:
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O....#....
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O.OO#....#
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.....##...
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OO.#O....O
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.O.....O#.
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O.#..O.#.#
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..O..#O..O
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.......O..
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#....###..
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#OO..#....
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Start by tilting the lever so all of the rocks will slide north as far as
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they will go:
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OOOO.#.O..
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OO..#....#
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OO..O##..O
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O..#.OO...
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........#.
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..#....#.#
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..O..#.O.O
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..O.......
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#....###..
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#....#....
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You notice that the support beams along the north side of the platform are
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damaged; to ensure the platform doesn't collapse, you should calculate the
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total load on the north support beams.
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The amount of load caused by a single rounded rock (O) is equal to the
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number of rows from the rock to the south edge of the platform, including
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the row the rock is on. (Cube-shaped rocks (#) don't contribute to load.)
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So, the amount of load caused by each rock in each row is as follows:
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OOOO.#.O.. 10
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OO..#....# 9
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OO..O##..O 8
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O..#.OO... 7
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........#. 6
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..#....#.# 5
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..O..#.O.O 4
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..O....... 3
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#....###.. 2
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#....#.... 1
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The total load is the sum of the load caused by all of the rounded rocks.
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In this example, the total load is 136.
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Tilt the platform so that the rounded rocks all roll north. Afterward,
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what is the total load on the north support beams?
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Your puzzle answer was 108813.
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--- Part Two ---
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The parabolic reflector dish deforms, but not in a way that focuses the
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beam. To do that, you'll need to move the rocks to the edges of the
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platform. Fortunately, a button on the side of the control panel labeled
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"spin cycle" attempts to do just that!
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Each cycle tilts the platform four times so that the rounded rocks roll
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north, then west, then south, then east. After each tilt, the rounded
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rocks roll as far as they can before the platform tilts in the next
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direction. After one cycle, the platform will have finished rolling the
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rounded rocks in those four directions in that order.
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Here's what happens in the example above after each of the first few
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cycles:
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After 1 cycle:
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.....#....
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....#...O#
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...OO##...
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.OO#......
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.....OOO#.
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.O#...O#.#
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....O#....
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......OOOO
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#...O###..
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#..OO#....
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After 2 cycles:
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.....#....
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....#...O#
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.....##...
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..O#......
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.....OOO#.
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.O#...O#.#
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....O#...O
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.......OOO
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#..OO###..
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#.OOO#...O
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After 3 cycles:
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.....#....
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....#...O#
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.....##...
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..O#......
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.....OOO#.
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.O#...O#.#
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....O#...O
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.......OOO
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#...O###.O
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#.OOO#...O
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This process should work if you leave it running long enough, but you're
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still worried about the north support beams. To make sure they'll survive
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for a while, you need to calculate the total load on the north support
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beams after 1000000000 cycles.
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In the above example, after 1000000000 cycles, the total load on the north
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support beams is 64.
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Run the spin cycle for 1000000000 cycles. Afterward, what is the total
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load on the north support beams?
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Your puzzle answer was 104533.
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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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You can also [Shareon [19]Twitter [20]Mastodon] this puzzle.
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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/2023/about
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3. https://adventofcode.com/2023/events
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4. https://teespring.com/stores/advent-of-code
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5. https://adventofcode.com/2023/settings
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6. https://adventofcode.com/2023/auth/logout
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7. Advent of Code Supporter
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https://adventofcode.com/2023/support
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8. https://adventofcode.com/2023
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9. https://adventofcode.com/2023
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10. https://adventofcode.com/2023/support
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11. https://adventofcode.com/2023/sponsors
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12. https://adventofcode.com/2023/leaderboard
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13. https://adventofcode.com/2023/stats
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14. https://adventofcode.com/2023/sponsors
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15. https://www.janestreet.com/
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16. https://en.wikipedia.org/wiki/Parabolic_reflector
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17. https://adventofcode.com/2023
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18. https://adventofcode.com/2023/day/14/input
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19. https://twitter.com/intent/tweet?text=I%27ve+completed+%22Parabolic+Reflector+Dish%22+%2D+Day+14+%2D+Advent+of+Code+2023&url=https%3A%2F%2Fadventofcode%2Ecom%2F2023%2Fday%2F14&related=ericwastl&hashtags=AdventOfCode
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20. javascript:void(0);
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