diff --git a/2024/day19/problem b/2024/day19/problem new file mode 100644 index 0000000..4c6aab4 --- /dev/null +++ b/2024/day19/problem @@ -0,0 +1,151 @@ +Advent of Code + +--- Day 19: Linen Layout --- + + Today, The Historians take you up to the [16]hot springs on Gear Island! + Very [17]suspiciously, absolutely nothing goes wrong as they begin their + careful search of the vast field of helixes. + + Could this finally be your chance to visit the [18]onsen next door? Only + one way to find out. + + After a brief conversation with the reception staff at the onsen front + desk, you discover that you don't have the right kind of money to pay the + admission fee. However, before you can leave, the staff get your + attention. Apparently, they've heard about how you helped at the hot + springs, and they're willing to make a deal: if you can simply help them + arrange their towels, they'll let you in for free! + + Every towel at this onsen is marked with a pattern of colored stripes. + There are only a few patterns, but for any particular pattern, the staff + can get you as many towels with that pattern as you need. Each stripe can + be white (w), blue (u), black (b), red (r), or green (g). So, a towel with + the pattern ggr would have a green stripe, a green stripe, and then a red + stripe, in that order. (You can't reverse a pattern by flipping a towel + upside-down, as that would cause the onsen logo to face the wrong way.) + + The Official Onsen Branding Expert has produced a list of designs - each a + long sequence of stripe colors - that they would like to be able to + display. You can use any towels you want, but all of the towels' stripes + must exactly match the desired design. So, to display the design rgrgr, + you could use two rg towels and then an r towel, an rgr towel and then a + gr towel, or even a single massive rgrgr towel (assuming such towel + patterns were actually available). + + To start, collect together all of the available towel patterns and the + list of desired designs (your puzzle input). For example: + + r, wr, b, g, bwu, rb, gb, br + + brwrr + bggr + gbbr + rrbgbr + ubwu + bwurrg + brgr + bbrgwb + + The first line indicates the available towel patterns; in this example, + the onsen has unlimited towels with a single red stripe (r), unlimited + towels with a white stripe and then a red stripe (wr), and so on. + + After the blank line, the remaining lines each describe a design the onsen + would like to be able to display. In this example, the first design + (brwrr) indicates that the onsen would like to be able to display a black + stripe, a red stripe, a white stripe, and then two red stripes, in that + order. + + Not all designs will be possible with the available towels. In the above + example, the designs are possible or impossible as follows: + + • brwrr can be made with a br towel, then a wr towel, and then finally + an r towel. + • bggr can be made with a b towel, two g towels, and then an r towel. + • gbbr can be made with a gb towel and then a br towel. + • rrbgbr can be made with r, rb, g, and br. + • ubwu is impossible. + • bwurrg can be made with bwu, r, r, and g. + • brgr can be made with br, g, and r. + • bbrgwb is impossible. + + In this example, 6 of the eight designs are possible with the available + towel patterns. + + To get into the onsen as soon as possible, consult your list of towel + patterns and desired designs carefully. How many designs are possible? + + Your puzzle answer was 311. + +--- Part Two --- + + The staff don't really like some of the towel arrangements you came up + with. To avoid an endless cycle of towel rearrangement, maybe you should + just give them every possible option. + + Here are all of the different ways the above example's designs can be + made: + + brwrr can be made in two different ways: b, r, wr, r or br, wr, r. + + bggr can only be made with b, g, g, and r. + + gbbr can be made 4 different ways: + + • g, b, b, r + • g, b, br + • gb, b, r + • gb, br + + rrbgbr can be made 6 different ways: + + • r, r, b, g, b, r + • r, r, b, g, br + • r, r, b, gb, r + • r, rb, g, b, r + • r, rb, g, br + • r, rb, gb, r + + bwurrg can only be made with bwu, r, r, and g. + + brgr can be made in two different ways: b, r, g, r or br, g, r. + + ubwu and bbrgwb are still impossible. + + Adding up all of the ways the towels in this example could be arranged + into the desired designs yields 16 (2 + 1 + 4 + 6 + 1 + 2). + + They'll let you into the onsen as soon as you have the list. What do you + get if you add up the number of different ways you could make each design? + + Your puzzle answer was 616234236468263. + + Both parts of this puzzle are complete! They provide two gold stars: ** + + At this point, you should [19]return to your Advent calendar and try + another puzzle. + + If you still want to see it, you can [20]get your puzzle input. + +References + + Visible links + 1. https://adventofcode.com/ + 2. https://adventofcode.com/2024/about + 3. https://adventofcode.com/2024/events + 4. https://cottonbureau.com/people/advent-of-code + 5. https://adventofcode.com/2024/settings + 6. https://adventofcode.com/2024/auth/logout + 7. Advent of Code Supporter + https://adventofcode.com/2024/support + 8. https://adventofcode.com/2024 + 9. https://adventofcode.com/2024 + 10. https://adventofcode.com/2024/support + 11. https://adventofcode.com/2024/sponsors + 12. https://adventofcode.com/2024/leaderboard + 13. https://adventofcode.com/2024/stats + 16. https://adventofcode.com/2023/day/12 + 17. https://www.youtube.com/watch?v=ekL881PJMjI + 18. https://en.wikipedia.org/wiki/Onsen + 19. https://adventofcode.com/2024 + 20. https://adventofcode.com/2024/day/19/input