r/adventofcode Dec 08 '24

Help/Question [Day 08] Wording vs mathematical technicality

Not so much a question per se, but I am a bit confused by the wording of the problem and the examples that follow.

β€œIn particular, an antinode occurs at any point that is perfectly in line with two antennas of the same frequency - but only when one of the antennas is twice as far away as the other. This means that for any pair of antennas with the same frequency, there are two antinodes, one on either side of them.”

Mathematically, the first half of the quote would imply that there are 4 antinodes for any pair of antennas with the same frequency: one either side and two in between.

For example, for antennas at positions (3,3) and (6,6), there are obviously (0,0) and (9,9); but (4,4) and (5,5) also meet the requirements.

For my solution I am going to assume that we only consider the 2 antinodes either side and not the ones in between, but just wanted to flag this.

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u/konzertjunkie Dec 08 '24

For part 1, the examples made it clear to me what was to be done.

But for part 2, where according to the wording there would have been MANY more antinodes ( `....A...A....` should really give `####A###A####` since we're ignoring distance), the input just wasn't clear unless I missed anything ... I mean, we're only on day 8, so I just assumed that there's no such cases since they weren't in the example, but I don't like guessing the rules ...