CareerCup

O(n) algorithm for n shops

case class Coordinate(x: Double, y: Double)
case class Shop(c: Coordinate, name: String)

object NearestDistanceToShop {
  def findNearestShop(shops: Seq[Shop], person: Coordinate): Option[Shop] = {
    if (shops.isEmpty) {
      return None
    }

    val (goodShop, _) = shops.foldLeft((None.asInstanceOf[Option[Shop]], -1.asInstanceOf[Double])) { case ((closestShop, shortestDistance), shop) =>
      val shopCoord = shop.c
      val distance = Math.sqrt(Math.pow(shopCoord.x - person.x, 2) + Math.pow(shopCoord.y - person.y, 2))
      if (-1 == shortestDistance || distance < shortestDistance) {
        (Some(shop), distance)
      } else {
        (closestShop, shortestDistance)
      }
    }
    goodShop
  }
}

// Scala version

import scala.io.Source

object UniqueLinesInFiles {
  def findUniqueLines(filenames: Seq[String]): Seq[String] = {
    filenames.foldLeft(Map.empty[Int, Set[String]])((linesMap, filename) => {
      Source.fromFile(filename).getLines.foldLeft(linesMap)((memo, line) => {
        memo.get(line.length()) match {
          case Some(linesOfLength) => {
            /*
            This block could also be simplified to just:
            memo + (line.length() -> (linesOfLength + line))
             */
            if (linesOfLength.contains(line)) {
              memo
            } else {
              memo + (line.length() -> (linesOfLength + line))
            }
          }
          case None => {
            memo + (line.length() -> Set(line))
          }
        }
      })
    }).foldLeft(Set.empty[String]) { case (memo, (_, lines)) => memo ++ lines }.toSeq
  }
}