Day 9: Mirage Maintenance

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[-] mykl@lemmy.world 3 points 1 year ago* (last edited 1 year ago)

Dart

I was getting a bad feeling when it explained in such detail how to solve part 1 that part 2 was going to be some sort of nightmare of traversing all those generated numbers in some complex fashion, but this has got to be one of the shortest solutions I've ever written for an AoC challenge.

int nextTerm(Iterable ns) {
  var diffs = ns.window(2).map((e) => e.last - e.first);
  return ns.last +
      ((diffs.toSet().length == 1) ? diffs.first : nextTerm(diffs.toList()));
}

List> parse(List lines) => [
      for (var l in lines) [for (var n in l.split(' ')) int.parse(n)]
    ];

part1(List lines) => parse(lines).map(nextTerm).sum;
part2(List lines) => parse(lines).map((e) => nextTerm(e.reversed)).sum;

this post was submitted on 09 Dec 2023

21 points (95.7% liked)

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.

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