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// P01
def last[A](l: List[A]): A = l match{
  case n :: Nil => n
  case n :: next => last(next)
  case _ => throw new NoSuchElementException
}

// P02
def penultimate[A](l: List[A]): A = l match{
  case n :: m :: Nil => n

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// P11
def encodeModified[A](ls: Seq[A]): Seq[Any] = encode(ls) map {t => if(t._1 == 1) t._2 else t}

// P12
def decode[A](ls: Seq[(Int, A)]): Seq[A] = ls flatMap(n => List.fill(n._1)(n._2))

// P13
def encodeDirect[A](ls: Seq[A]): Seq[(Int, A)] = {
  if (ls.isEmpty) Nil
  else{

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// P21
def insertAt[A](e: A, i: Int, ls: Seq[A]): Seq[A] = ls.take(i) ++ Seq(e) ++ ls.drop(i)

// P22
def range(start: Int, end: Int): Seq[Int] = Seq.range(start, end+1)

def rangeR(start: Int, end: Int): Seq[Int] = {
  def rangeRR(value: Int, result: Seq[Int]): Seq[Int] = {
    if(value < start) result
    else rangeRR(value-1, value +: result)

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// P26
// 大門.scala gist(https://gist.github.com/1183495)よりほぼ転載
def sublists[A](ls: List[A]): List[List[A]] = ls match{
  case Nil => Nil
  case _ :: tail => ls :: sublists(tail)
}

def combinations[A](n: Int, ls: List[A]): List[List[A]] = {
  if (n == 0) List(Nil)
  else{

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// P31
case class P31(n: Int){
  lazy val isPrime: Boolean = Iterator.from(2).takeWhile(i => i*i <= n).forall(n%_ != 0)
}

implicit def fromIntToP31(n: Int): P31 = P31(n)

// P32
def gcd(a: Int, b: Int): Int = if(b == 0) a else gcd(b, a%b)

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// P46
def and(a: Boolean, b: Boolean) = a && b
def or(a: Boolean, b: Boolean) = a || b
def nand(a: Boolean, b: Boolean) = !(a && b)
def nor(a: Boolean, b: Boolean) = !(a || b)
def impl(a: Boolean, b: Boolean) = a && b
def equ(a: Boolean, b: Boolean) = !a || b
def xor(a: Boolean, b: Boolean) = a ^ b
def not(a: Boolean) = !a

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// P50
abstract sealed class Node[A]{
  val freq: Int
}

case class Leaf[A](element: A, freq: Int) extends Node[A]
case class Branch[A](left: Node[A], right: Node[A]) extends Node[A]{
  val freq = left.freq + right.freq
}

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// http://d.hatena.ne.jp/kmizushima/20090629/1246212207
// 写経+α(関数少し変えただけ)
// 改行の練習になった気がする．

object Houses extends Enumeration{
  val red = Value("Red")
  val white = Value("White")
  val green = Value("Green")
  val yellow = Value("Yellow")
  val blue = Value("Blue")

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#!/bin/sh                                                                                       
                                                                                                
if [ $# -ne 1 ] ; then                                                                          
    echo "usage: sbtg project_name" 1>&2                                                        
    exit 1                                                                                      
fi                                                                                              
                                                                                                
echo "name := \"$1\"\n" > build.sbt                                                             
echo 'version := "1.0"\n' >> build.sbt                                                          
echo 'scalaVersion := "2.9.1"\n' >> build.sbt                                                   

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name := "project_name"

version := "1.0"

scalaVersion := "2.9.1"

libraryDependencies += "org.scalatest" %% "scalatest" % "1.7.1" % "test"

/** Console */
initialCommands in console := "import org.scalatest.FunSuite"