AndrewTweddle

0..10 | % { python GuessClosedForm.py "i ** $_"; Write-Host }

AndrewTweddle

import jhm.JHMSolver
import jhm.SolverUsingFlatMap
import jhm.SolverUsingFor
import jhm.SolverUsingFoldLeft

object JHMWorksheet {
  implicit val repetitions: Int = 20              //> repetitions  : Int = 20
  
  // Adapted from code found on: http://stackoverflow.com/questions/9160001/how-to-profile-methods-in-scala ...
  // UPDATE: see the following article for why this is a bad idea... http://shipilev.net/blog/2014/nanotrusting-nanotime/

AndrewTweddle

package jhm

case class SolverUsingFoldLeft( digits: String, total: Int, maxDigitsPerNumber: Int = 5
                              ) extends JHMSolver(digits, total, maxDigitsPerNumber) {

  case class PartialSolution( val partialStr: String, val partialNumber: Int,
                              val subTotal: Int, val numbersInReverse: List[Int] )
  {
    def runningSubTotal = subTotal + partialNumber
    def isInitialSolution = partialStr == ""

AndrewTweddle

package jhm

case class SolverUsingFor( digits: String, total: Int, maxDigitsPerNumber: Int = 5
                    ) extends JHMSolver(digits, total, maxDigitsPerNumber) {

  override def solve(digits: String, total: Int, maxDigitsPerNumber: Int = 5): List[List[Int]] = for {
    leftCount <- (1 to maxDigitsPerNumber).toList
    if leftCount <= digits.length
    (leftStr, rightStr) = digits.splitAt(leftCount)
    if (leftCount == 1 || leftStr(0) != '0')  // No numbers may start with '0' (except zero)

AndrewTweddle

package jhm

case class SolverUsingFlatMap( digits: String, total: Int, maxDigitsPerNumber: Int = 5
                        ) extends JHMSolver(digits, total, maxDigitsPerNumber) {

  override def solve(digits: String, total: Int, maxDigitsPerNumber: Int = 5): List[List[Int]] = {
    
    def getSolutionsForNextNumber(leftCount: Int): List[List[Int]] = {
      val (leftStr, rightStr) = digits.splitAt(leftCount)
      if (leftCount > 1 && leftStr(0) == '0') List.empty // Disallow numbers starting with zero

AndrewTweddle

package jhm

abstract class JHMSolver(digits: String, total: Int, maxDigitsPerNumber: Int = 5)
{
  def solve(digits: String, total: Int, maxDigitsPerNumber: Int = 5): List[List[Int]]
  
  lazy val solutions = solve(digits, total, maxDigitsPerNumber)

  def getSolutionsAsString(): String = solutions match {
    case Nil => "IMPOSSIBLE"

AndrewTweddle

function calc { 
  param (
    [String] $str, 
    [int] $target
  )
  foreach ($len in 1..5 ) {
    $firstStr = $str.SubString(0, $len)
    if ($firstStr.Length -lt $len) {
      break
    }