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BubbleSort.scala
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BubbleSort.scala
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package sortingAlgorithms
import scala.annotation.tailrec
/**
* This object contains function, that realises bubble sorting algorithm.
*
* https://en.wikipedia.org/wiki/Bubble_sort
*
* Worst speed: O(pow(n))
*
* Average speed: O(pow(n))
*
* Best speed: O(n)
*
* Purity project by Daniil Tekunov.
*/
object BubbleSort {
def bubbleSort(basicList: List[Int]): List[Int] = basicList match {
case List() => List()
case _ => bubble(basicList, Nil, Nil)
}
@tailrec
private def bubble(basic: List[Int], rest: List[Int], sorted: List[Int]): List[Int] = basic match {
// If we have a single element in a basic list
case element :: Nil =>
// end the rest list is empty, we add that element to a sorted list
if (rest.isEmpty) element :: sorted
// else we add this element to a sorted list and call the function again, without that element
else bubble(rest, Nil, element :: sorted)
// If we have 2+ elements
case firstElement :: secondElement :: next =>
// if first found element is greater, than another, we call the function again, without second element
// and we add second element to the rest list
if (firstElement > secondElement) bubble(firstElement :: next, secondElement :: rest, sorted)
//else we realize that operation, via swapped elements
else bubble(secondElement :: next, firstElement :: rest, sorted)
}
}