35 lines
1.1 KiB
Scala
35 lines
1.1 KiB
Scala
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package aoc.day11
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import aoc._
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import scala.annotation.tailrec
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val board = lines.toSeq
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// part 1
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val countByRow = board.map(_.count(_ == '#')).toList
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val countByCol = (0 until board(0).length()).map(col => board.count(row => row(col) == '#')).toList
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@tailrec def totalDist(expandBy: Int)(count: Long, leftDist: Long, accum: Long)(counts: List[Int]): Long =
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counts match
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case Nil => accum
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case 0 :: next => totalDist(expandBy)(count, leftDist + expandBy * count /* expanded case */, accum)(next)
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case cur :: next =>
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totalDist(expandBy)(count + cur, leftDist + count + cur, accum + cur * leftDist)(next)
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def totalDist(expandBy: Int)(counts: List[Int]): Long = totalDist(expandBy)(0, 0, 0)(counts)
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def part1 =
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inline def count(r: List[Int]): Long = totalDist(2)(r)
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val res = count(countByRow) + count(countByCol)
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println(res)
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def part2 =
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inline def count(r: List[Int]): Long = totalDist(1_000_000)(r)
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val res = count(countByRow) + count(countByCol)
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println(res)
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@main def Day11(part: Int) = part match
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case 1 => part1
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case 2 => part2
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