alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Scala example source code file (binarytrees.scala)

This example Scala source code file (binarytrees.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Scala tags/keywords

array, empty, empty, int, int, node, node, string, tree, tree

The Scala binarytrees.scala source code

/*
  The Computer Language Shootout
  http://shootout.alioth.debian.org/

  - tree: disjoint union type
  - loop: "for" loop over iterator range

  Contributed by Kannan Goundan
  De-optimized by Isaac Gouy
*/

object binarytrees {

  abstract class Tree;
  case class Node(i: Int, left: Tree, right: Tree) extends Tree
  case class Empty() extends Tree

  def check(tree: Tree) : Int = tree match {
    case Node(i, left, right) => i + check(left) - check(right)
    case Empty() => 0
  }

  def make(i: Int, depth: Int) : Tree = depth match {
/*  case 0 => Empty() */
    case 0 => Node(i, Empty(), Empty())
    case _ => Node(i, make((2*i)-1, depth-1), make(2*i, depth-1))
  }

  def main(args: Array[String]) = {
    val n = try { Integer.parseInt(args(0)) } catch { case _ => 1 }
    val minDepth = 4
    val maxDepth = Math.max(minDepth+2, n)

    print("stretch tree", maxDepth+1, check(make(0, maxDepth+1)))

    val longLived = make(0, maxDepth)

    for (val depth <- Iterator.range(minDepth, maxDepth+1, 2)) {
      val iterations = 1 << (maxDepth - depth + minDepth)

      var sum = 0
      for (val i <- Iterator.range(1, iterations+1))
        sum = sum + check(make(i, depth)) + check(make(-i, depth))

      print(iterations*2 + "\t trees", depth, sum)
    }

    print("long lived tree", maxDepth, check(longLived))
  }

  def print(name: String, depth: Int, check: Int) =
    Console.println(name + " of depth " + depth + "\t check: " + check)
}

Other Scala examples (source code examples)

Here is a short list of links related to this Scala binarytrees.scala source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.