Padovan sequence: Difference between revisions

=={{header|Scala}}==

{{trans|Java}}

<syntaxhighlight lang="scala">object Padovan extends App {

val recurrences = new collection.mutable.ListBuffer[Int]()

val floors = new collection.mutable.ListBuffer[Int]()

val PP = 1.324717957244746025960908854

val SS = 1.0453567932525329623

for (i <- 0 until 64) {

recurrences += padovanRecurrence(i)

floors += padovanFloor(i)

}

println("The first 20 terms of the Padovan sequence:")

recurrences.slice(0, 20).foreach(term => print(s"${term} "))

println("\n")

println(s"Recurrence and floor functions agree for first 64 terms? ${recurrences == floors}")

println("")

val words = createLSystem()

println("The first 10 terms of the L-system:")

words.slice(0, 10).foreach(term => print(term + " "))

println("\n")

print("Length of first 32 terms produced from the L-system match Padovan sequence? ")

val wordLengths = words.map(_.length)

print(wordLengths.slice(0, 32) == recurrences.slice(0, 32))

def padovanRecurrence(n: Int): Int = {

if (n <= 2) 1 else recurrences(n - 2) + recurrences(n - 3)

}

def padovanFloor(aN: Int): Int = {

scala.math.floor(scala.math.pow(PP, aN - 1) / SS + 0.5).toInt

}

def createLSystem(): List[String] = {

var words = List("A")

var text = "A"

while (words.length < 32) {

text = text.flatMap {

case 'A' => "B"

case 'B' => "C"

case 'C' => "AB"

}

words = words :+ text

}

words

}

}</syntaxhighlight>

{{out}}

<pre>

The first 20 terms of the Padovan sequence:

1 1 1 2 2 3 4 5 7 9 12 16 21 28 37 49 65 86 114 151

Recurrence and floor functions agree for first 64 terms? true

The first 10 terms of the L-system:

A B C AB BC CAB ABBC BCCAB CABABBC ABBCBCCAB

Length of first 32 terms produced from the L-system match Padovan sequence? true

</pre>