object Solution {

import scala.collection.mutable._

def checkInclusion(s1: String, s2: String): Boolean = {

val diffMap = HashMap.empty[Char, Int]

s1.foreach(updateMap(diffMap, _, 1))

(0 until s2.length).toList.exists(index => {

if (index >= s1.length) updateMap(diffMap, s2(index - s1.length), 1)

updateMap(diffMap, s2(index), -1)

diffMap.isEmpty

})

}

def updateMap(map: HashMap[Char, Int], char: Char, incrementer: Int): Unit =

map.get(char) match {

case Some(number) if number + incrementer == 0 => map -= char

case Some(number) => map += (char -> (number + incrementer))

case None => map += (char -> incrementer)

}

}