46 lines
1.4 KiB
Scala
46 lines
1.4 KiB
Scala
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// Part 1
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def literalDigits(s: String) =
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s.toSeq.filter(_.isDigit).map(v => (v - '0').toInt)
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def getValue(toDigits: String => Seq[Int])(s: String): Int =
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val digits = toDigits(s)
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digits.head * 10 + digits.last
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def iterate[T](get: => T | Null) = new scala.collection.IterableOnce[T]:
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override def iterator = new Iterator[T]:
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var item: Option[T | Null] = None
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override def hasNext: Boolean =
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if item.isEmpty then item = Some(get)
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item.get != null
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override def next(): T =
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val r = item.get.nn
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item = None
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r
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def getSum(toDigits: String => Seq[Int]) =
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val values =
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Seq.from(iterate(scala.io.StdIn.readLine())).map(getValue(toDigits))
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println(values.sum)
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// Part 2
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val englishDigits =
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Seq("one", "two", "three", "four", "five", "six", "seven", "eight", "nine")
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def literalOrEnglishDigits(s: String) =
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@scala.annotation.tailrec
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def loop(idx: Int, accum: Seq[Int]): Seq[Int] =
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if idx < 0 then accum
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else if s(idx).isDigit then loop(idx - 1, (s(idx) - '0').toInt +: accum)
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else
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val toMatch = s.slice(idx, idx + 5 /* enough to match english */ )
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val digit = englishDigits.indexWhere(toMatch.startsWith _)
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val nAccum = if digit == -1 then accum else (digit + 1) +: accum
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loop(idx - 1, nAccum)
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loop(s.length() - 1, Seq.empty)
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@main def Run(part: Int) = part match
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case 1 => getSum(literalDigits)
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case 2 => getSum(literalOrEnglishDigits)
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