this post was submitted on 05 Dec 2023
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Advent Of Code
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Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.
AoC 2023
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console.log('Hello World')
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"Set operations" should probably be in quotes. I just mean that I implemented the
*(intersection) and-(difference) operators for my ValueRange type. The intersection operator works like it does for sets, just returning the overlap. The difference operator has to work a little differently, because ranges have to be contiguous, whereas sets don't, so it returns a sequence of ValueRange objects.My ValueMapping type uses a ValueRange for it's source, so applying it to a range just involves using the intersection operator to determine what part of the range needs to move, and the difference operator to determine which parts are left.
Well, then we have the same solution but coded very differently. Here's mine.
ruleAppliedis one function with almost all logic. I take a range and compare it to a rule's source range (50 98 2 is a rule). Overlaps get transformed and collected into the first sequence and everything that left goes in the second. I need twoseqs there, for transformed values to skip next rules in the same map.Repeat for each rule and each map (seq[Rule]). And presto, it's working!
Yeah, roughly the same idea. I guess I could have just used HSlice for my range type, I thought maybe there was some special magic to it.
It looks like your if-else ladder misses a corner case, where one range only intersects with the first or last element of the other. Switching to
<=and>=for those should take care of it though.Thank you, should be fixed now.