35 lines
1.4 KiB
Scala
35 lines
1.4 KiB
Scala
val fileSizePattern = raw"(\d+) ([\w.]+)".r
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val cdPattern = "\\$ cd ([\\/\\w.]+)".r // raw string interpolation doesn't like \$
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val rootPattern = raw"\/(.*)".r
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def cd(cwd: String, to: String): String = to match
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case rootPattern(absPath) => absPath // Absolute path
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case ".." =>
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val i = cwd lastIndexOf '/'
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if i < 0 then cwd else cwd.substring(0, i) // Up one subfolder
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case _ => s"$cwd/$to"
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@main def main() =
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val inputLines = scala.io.Source.fromFile("input/07").getLines
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var cwd = "" // We append the / at time of use
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val folders = scala.collection.mutable.HashSet[String](cwd)
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val fileSizes = scala.collection.mutable.HashMap[String, Int]()
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for line <- inputLines do line match
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case cdPattern(dir) =>
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cwd = cd(cwd, dir)
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folders += cwd
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case fileSizePattern(sizeStr, filename) =>
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fileSizes += s"$cwd/$filename" -> sizeStr.toInt
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case _ => {} // "$ ls", "dir ..."
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// Very inefficient way of calculating folder sizes, but cute enough
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val folderSizes = folders.map(f => (f, fileSizes.filter((k,v) => k startsWith s"$f/").values.sum)).toMap
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println(s"Part 1: ${folderSizes.values.filter(v => v <= 100_000).sum}")
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val totalCapacity = 70_000_000
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val desiredRemaining = 30_000_000
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val currentRemaining = totalCapacity - folderSizes("")
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val sizeToDelete = desiredRemaining - currentRemaining
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println(s"Part 2: ${folderSizes.values.filter(v => v > sizeToDelete).min}")
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