From cb6ba28dcdc4c4068956bb11147ff15110d2f1c3 Mon Sep 17 00:00:00 2001 From: Gabriel Kastenbaum Date: Thu, 7 Jul 2011 23:34:03 +0200 Subject: [PATCH 1/2] P019 with some Traits to structur the problems --- src/.gitignore | 2 ++ src/p019.scala | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 92 insertions(+) create mode 100644 src/.gitignore create mode 100644 src/p019.scala diff --git a/src/.gitignore b/src/.gitignore new file mode 100644 index 0000000..4ee43af --- /dev/null +++ b/src/.gitignore @@ -0,0 +1,2 @@ +*.class +*~ diff --git a/src/p019.scala b/src/p019.scala new file mode 100644 index 0000000..b29ba29 --- /dev/null +++ b/src/p019.scala @@ -0,0 +1,90 @@ +import scala.util.matching.Regex + +trait Solution { + val pattern = new Regex("""(.*)\$(.*)\$""", "problem", "solutionName"); + def simpleName:String=pattern.findFirstMatchIn(this.getClass.getSimpleName).get.group ("solutionName") +} +trait SolutionP019 extends Solution { + def rotate[T] (n:Int, l:List[T]):List[T] +} + +trait Solutions[Problem] { + def doc():String + def tests () + def implementations ():List[Problem] +} + +object p019 extends Solutions[SolutionP019]{ + def main(args: Array[String]) = { + println (doc) + tests + } + + def doc = """ + http://aperiodic.net/phil/scala/s-99/p19.scala + P19 (**) Rotate a list N places to the left. + Examples: + scala> rotate(3, List('a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, 'k)) + res0: List[Symbol] = List('d, 'e, 'f, 'g, 'h, 'i, 'j, 'k, 'a, 'b, 'c) + + scala> rotate(-2, List('a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, 'k)) + res1: List[Symbol] = List('j, 'k, 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i) + """ + + def tests()={ + for (sol <- implementations) { + print ("Test implementation " + sol.simpleName) + + + val expected=List('d, 'e, 'f, 'g, 'h, 'i, 'j, 'k, 'a, 'b, 'c) + val result=sol.rotate(3, List('a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, 'k)) + require(expected==result) + println (" : OK ") + } + } + + def implementations ()=List(DavidBernard, AlexisAgahi, AriéBénichou ) + + object DavidBernard extends SolutionP019 { + def rotate[A](k:Int, l:List[A]) = if(l.isEmpty) Nil else { + val nk = k % l.length + val pk = if(k < 0) l.length + k else k + l.drop(pk) ::: l.take(pk) + } + } + + object BenjaminLerman extends SolutionP019 { + def rotate[A](k:Int, l:List[A]) = if(l.isEmpty) Nil else { + val nk = k % l.length + val pk = if(k < 0) l.length + nk else nk + l.drop(pk) ::: l.take(pk) + } + } + + object AlexisAgahi extends SolutionP019 { + def rotate[T]( n:Int, list:List[T]):List[T] = { + val size = list.size + require( size > 0 ) + val i = if( n < 0) size + n % size else n % size + val (l1, l2 ) = list.splitAt( i ) + l2 ::: l1 + } + } + + object AriéBénichou extends SolutionP019 { + + + def rotate[T](n: Int, ls: List[T]): List[T] = { + if (ls == null) + return Nil + + val length = ls.length + if (length == 0) + return Nil + + val (l, r) = ls.splitAt(if (n < 0) length + n % length else n % length); + r ::: l + } + } +} + From e13dc6e857bcdc1a9f43f080fd2bdcef580a294f Mon Sep 17 00:00:00 2001 From: Gabriel Kastenbaum Date: Fri, 8 Jul 2011 00:03:06 +0200 Subject: [PATCH 2/2] Better structure --- src/p019.scala | 20 -------------------- src/p020.scala | 23 +++++++++++++++++++++++ src/problems.scala | 26 ++++++++++++++++++++++++++ 3 files changed, 49 insertions(+), 20 deletions(-) create mode 100644 src/p020.scala create mode 100644 src/problems.scala diff --git a/src/p019.scala b/src/p019.scala index b29ba29..0ac0c70 100644 --- a/src/p019.scala +++ b/src/p019.scala @@ -1,24 +1,4 @@ -import scala.util.matching.Regex - -trait Solution { - val pattern = new Regex("""(.*)\$(.*)\$""", "problem", "solutionName"); - def simpleName:String=pattern.findFirstMatchIn(this.getClass.getSimpleName).get.group ("solutionName") -} -trait SolutionP019 extends Solution { - def rotate[T] (n:Int, l:List[T]):List[T] -} - -trait Solutions[Problem] { - def doc():String - def tests () - def implementations ():List[Problem] -} - object p019 extends Solutions[SolutionP019]{ - def main(args: Array[String]) = { - println (doc) - tests - } def doc = """ http://aperiodic.net/phil/scala/s-99/p19.scala diff --git a/src/p020.scala b/src/p020.scala new file mode 100644 index 0000000..3f8203a --- /dev/null +++ b/src/p020.scala @@ -0,0 +1,23 @@ + +object p020 extends Solutions[SolutionP020]{ + def doc = """ + scala> removeAt(1, List('a, 'b, 'c, 'd)) + res0: (List[Symbol], Symbol) = (List('a, 'c, 'd),'b) + """ + + def tests ()={ + for (sol <- implementations) { + print ("Test implementation " + sol.simpleName) + val expected=(List('a, 'c, 'd),'b) + val result=sol.removeAt(1, List('a, 'b, 'c, 'd)) + require(expected==result) + println (" : OK ") + } + } + + def implementations ()=List(BenjaminLerman) + + object BenjaminLerman extends SolutionP020 { + def removeAt[A](k:Int, l:List[A]) = (l.take(k):::l.drop(k+1), l(k)) + } +} diff --git a/src/problems.scala b/src/problems.scala new file mode 100644 index 0000000..e6386ad --- /dev/null +++ b/src/problems.scala @@ -0,0 +1,26 @@ +import scala.util.matching.Regex + +trait Solution { + val pattern = new Regex("""(.*)\$(.*)\$""", "problem", "solutionName"); + def simpleName:String=pattern.findFirstMatchIn(this.getClass.getSimpleName).get.group ("solutionName") +} +trait Solutions[Problem] { + def doc():String + def tests () + def implementations ():List[Problem] + + def main(args: Array[String]) = { + println (doc) + tests + } +} + + + +trait SolutionP019 extends Solution { + def rotate[T] (n:Int, l:List[T]):List[T] +} + +trait SolutionP020 extends Solution { + def removeAt[T] (n:Int, l:List[T]):(List[T], T) +}