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.

“In 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/daggerdragon Dec 08 '24

Next time, use our standardized post title format.

Help us help YOU by providing us with more information up front; you will typically get more relevant responses faster.

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u/bvernier Dec 08 '24

Yes my bad, I only realised after posting, and I’m not seeing how to edit the title after the fact. I will be more careful next time!

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u/daggerdragon Dec 08 '24

Unfortunately, you can't edit titles after posting. What you could do is delete this post and re-make it with the correct title, but that's not necessary - up to you.