Mercurial > repos > other > adventofcode2023
comparison day16.txt @ 22:ad73a2ff3d06
Implement Day 15 part 1 and all of Day 16
Hash implementation was trivial, but I skipped the rest for now.
Day 16 part 1 approach works unchanged for part 2! Just needed
to run repeatedly with different inputs.
| author | IBBoard <dev@ibboard.co.uk> |
|---|---|
| date | Sat, 16 Dec 2023 14:42:06 +0000 |
| parents | |
| children |
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| 21:46fb65f2cb94 | 22:ad73a2ff3d06 |
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| 1 --- Day 16: The Floor Will Be Lava --- | |
| 2 | |
| 3 A laser/mirror problem - "/" and "\" are mirrors that reflect 90°. | |
| 4 "-" and "|" are splitters - transparent in the same orientation, | |
| 5 but TWO beams go at 90° if hit against the flat edge. | |
| 6 "." is empty space. | |
| 7 | |
| 8 The laser starts in the top-right. | |
| 9 | |
| 10 For an example map: | |
| 11 | |
| 12 .|...\.... | |
| 13 |.-.\..... | |
| 14 .....|-... | |
| 15 ........|. | |
| 16 .......... | |
| 17 .........\ | |
| 18 ..../.\\.. | |
| 19 .-.-/..|.. | |
| 20 .|....-|.\ | |
| 21 ..//.|.... | |
| 22 | |
| 23 The laser goes: | |
| 24 | |
| 25 >|<<<\.... | |
| 26 |v-.\^.... | |
| 27 .v...|->>> | |
| 28 .v...v^.|. | |
| 29 .v...v^... | |
| 30 .v...v^..\ | |
| 31 .v../2\\.. | |
| 32 <->-/vv|.. | |
| 33 .|<<<2-|.\ | |
| 34 .v//.|.v.. | |
| 35 | |
| 36 Every space that the laser goes through is "energised", which gives: | |
| 37 | |
| 38 ######.... | |
| 39 .#...#.... | |
| 40 .#...##### | |
| 41 .#...##... | |
| 42 .#...##... | |
| 43 .#...##... | |
| 44 .#..####.. | |
| 45 ########.. | |
| 46 .#######.. | |
| 47 .#...#.#.. | |
| 48 | |
| 49 The count of energised spaces is 46. |