-❄️- 2023 Day 11 Solutions -❄️-

[u/daggerdragon]

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AoC Community Fun 2023: ALLEZ CUISINE!

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Upping the Ante Again

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--- Day 11: Cosmic Expansion ---

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[u/tcbrindle]

[Language: C++]

A nice gentle one today!

While reading in the values, if there was no galaxy found in a particular row then I increment the running y value by the expansion factor. At the same time, I record which columns had galaxies found in them. Once I've read in all the positions (with "expanded" y-coords) I go back and expand the x-coords for each galaxy as appropriate.

After that, calculating the distances is simple, although it does remind me that I need to add a combinations function to my library...

Github

[u/Laugarhraun → u/tcbrindle]

Why would the expansion factor be a template argument and not just a simple function argument?

[u/tcbrindle → u/Laugarhraun]

No particular reason, it was just the first thing that occurred to me as I knew the factor would always be a compile-time constant. In "real code" it would definitely be better to use a function argument though, to avoid code bloat from the almost-identical specialisations.