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object Polynomials
{
class Poly(terms0: Map[Int, Double]) {
def this(bindings: (Int, Double)*) = this(bindings.toMap)
val terms = terms0 withDefaultValue 0.0
def add (other: Poly) = new Poly(terms ++ (other.terms map adjust))
def adjust(term: (Int, Double)): (Int, Double) = {
val (exp, coeff) = term
exp -> (coeff + terms(exp))
// before adding defauld value
/* terms get exp match { */
/* case Some(coeff1) => exp -> (coeff + coeff1) */
/* case None => exp -> coeff */
/* } */
}
def + (other: Poly) = new Poly((other.terms foldLeft terms)(addTerm))
def addTerm(terms: Map[Int, Double], term: (Int, Double)) = {
val (exp, coeff) = term
terms + (exp -> (coeff + terms(exp)))
}
override def toString =
(for ((exp, coeff) <- terms.toList.sorted.reverse) yield coeff+"^"+exp) mkString " + "
}
def run = {
println("Polynomials")
/* val p1 = new Poly(Map(1 -> 2.0, 3 -> 4.0, 5 -> 6.2)) */
/* val p2 = new Poly(Map(0 -> 3.0, 3 -> 7.0)) */
val p1 = new Poly(1 -> 2.0, 3 -> 4.0, 5 -> 6.2)
val p2 = new Poly(0 -> 3.0, 3 -> 7.0)
println(p1.terms(7))
println(p1)
println(p2)
println(p1 add p2)
println(p1 + p2)
}
}
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