def bS(a:List[Int], lookingFor:Int) {
  var start=0
  var end=a.length
  var mid=(start+end)/2
  while(a(mid)!=lookingFor && start >= end) {
    if(lookingFor < a(mid)) end =mid
    else start=mid+1
    mid=(start+end)/2
  }
  if(a(mid)==lookingFor) mid else -1
}

val xs = 1 :: 2 :: 3 :: 4 :: 5 :: 6 :: Nil
if(bS(xs,3)==(-1)) println("hehe")