variance_hw

Just for understanding variance in scala

Tasks:

• implement all needed case class and case object for proposed traits

  trait ContrVOrdering[-T] {
    def compare(a: T, b: T): Int
  }

  and

  trait BiTree[+T] {
    def value: T
    def left: BiTree[T]
    def right: BiTree[T]
    def find(v: T): Option[T]
    def add[U/*Think about bound here*/](value: U)(implicit ord: ContrVOrdering[U]): BiTree[U]
  }

• write tests using scalatest
• write tests using scalacheck

NOTE: Feel free to extend / change any interface if needed.