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42 lines
1.2 KiB
Scala
42 lines
1.2 KiB
Scala
import scala.io.StdIn.readInt
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val MAX_X = 300
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val MAX_Y = 300
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case class Pos(x: Int, y: Int)
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def cellPower(serial: Int)(p: Pos): Int = {
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val rackId = p.x + 10
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(((((rackId * p.y) + serial) * rackId) / 100) % 10) - 5
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}
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// TODO Should not recompute stuff each time
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def squarePower(serial: Int, sqSize: Int)(p: Pos): Int = {
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(p.x to (p.x + sqSize - 1)).flatMap(x => (p.y to (p.y + sqSize - 1)).map(y => Pos(x, y))).map(cellPower(serial)).sum
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}
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/*
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println(cellPower(57)(Pos(122, 79)) + " expected -5")
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println(cellPower(39)(Pos(217, 196)) + " expected 0")
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println(cellPower(71)(Pos(101, 153)) + " expected 4")
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println(squarePower(18)(Pos(33,45)) + " expected 29")
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// */
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val input = readInt
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// Suboptimal, but works.
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Iterator.from(3, 1)
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.scanLeft((0, 0, None: Option[Pos])) {
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case ((max, maxSize, maxP), sqSize) => val p = (1 to (MAX_X - sqSize)).flatMap(x => (1 to (MAX_Y - sqSize)).map(y => Pos(x, y))).maxBy(squarePower(input, sqSize))
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val pPower = squarePower(input, sqSize)(p)
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if (pPower > max) {
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(pPower, sqSize, Some(p))
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} else {
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null
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}
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case _ => null
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}
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.takeWhile(_ != null)
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.map { case (max, size, pos) => s"Size $size -> Best pos = $pos with power $max" }
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.foreach(println)
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