Scala solution to problem: http://codeforces.com/problemset/problem/37/A

ATower.scala

object ATower {
  
	def lengthEncode(l: List[Int]):List[Tuple2[Int,Int]] = l match  {
  		case Nil => List()
  		case n::Nil => List((n,1))
  		case n::tail => val (repeats, rest) = tail.span(x=>x==n); (n,repeats.length+1) :: lengthEncode(rest)
  }                                              

  def towers(l1: String, l2:String):(Int,Int) = {
  	val lines = l1.toInt
  	val data = l2.split(" ").map(_.toInt).sorted.toList
    val lencoded = lengthEncode(data)
    val max = lencoded.maxBy(_._2)._2
    (max,lencoded.length)
  }                                                
  
  towers("4","6 5 6 7")                           //> res0: (Int, Int) = (2,3)
}