Permutation-In-String.scala

//almost the same as Question 17 , we use exists instead of filter to find the first permutation
objectSolution {
importscala.collection.mutable._

defcheckInclusion(s1: String, s2: String):Boolean= {
valdiffMap=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
 })
 }

defupdateMap(map: HashMap[Char, Int], char: Char, incrementer: Int):Unit=
 map.get(char) match {
caseSome(number) if number + incrementer ==0=> map -= char
caseSome(number) => map += (char -> (number + incrementer))
caseNone=> map += (char -> incrementer)
 }
}