Anagrams.scala

  implicit class RichMap[K, V](m: Map[K, V]) {
    def updateValue(k: K)(f: Option[V] => V): Map[K, V] = m + (k -> f(m get k))
    def incValue(k: K)(implicit ev: Numeric[V]): Map[K, V] =
      updateValue(k){ o =>
        val one = ev.fromInt(1)
        o map { ev.plus(_, one) } getOrElse one
    }