1. val C = io.Source.fromFile(today + "input").getLines.toList
  4. def parseMask(m: String) = m.zipWithIndex.filter(_._1 != 'X').map(x => (x._1 - '0', x._2)).map(_.swap).map(x => (35L - x._1.toLong, x._2.toLong)).toMap
  7. def flipBitAtIndex(cur: Long, mIndexBit: (Long, Long)): Long = {
  8. val (mIdx, bitFlip) = mIndexBit
  9. bitFlip match {
  10. case 1L ⇒ cur | (1L << mIdx)
  11. case 0L ⇒ cur & ~(1L << mIdx)
  12. }
  13. }
  15. var mask = Map[Long, Long]()
  16. var memory = Map[Long, Long]()
  18. C.foreach { line =>
  19. val command = line.split(" = ")
  20. if (command(0) == "mask") {
  21. mask = parseMask(command(1))
  22. } else {
  23. val index = command(0).substring(4, command(0).length - 1).toLong
  24. val value = command(1).toLong
  26. val maskedValue = mask.foldLeft(value)(flipBitAtIndex)
  27. memory = memory + (index -> maskedValue)
  28. }
  29. }
  31. println(memory.values.sum)

14 1