insert

def insert(pair: (Char, Int), xs: List[(Char, Int)]): List[(Char, Int)] = xs match {
      case List() => List(pair)
      case y :: ys => {
        if (pair._1 == y._1) (pair._1, y._2 + 1) :: ys
        else if (pair._1 < y._1) pair :: xs
        else y :: insert(pair, ys)
      }
}

def insert2(x: (Char, Int), xs: List[Leaf]): List[Leaf] = xs match {
	case List() => List(Leaf(x._1, x._2))
	case y :: ys => {
		if (x._2 < y.weight) Leaf(x._1, x._2) :: xs
		else y :: insert2(x, ys)
	}
}

def insertGeneral[T2](x: [T1], xs: List[T2], f: T1 => List[T2]): List[T2] = xs match {
      case Nil => f(x)
      case 
    }