Add cats tarai func

Author: zabio3

build.sbt

@@ -13,3 +13,6 @@ scalacOptions ++= Seq(
   "-Xlint" // その他、望ましい書き方や落とし穴についての情報
   // "-Xfatal-warnings" // 警告をエラーとして扱う
 )
+
+// cats-core: Most core type classes and functionality (required).
+libraryDependencies += "org.typelevel" %% "cats-core" % "1.0.1"

src/main/scala/BenchMark.scala

@@ -4,7 +4,9 @@ object BenchMark extends App {
 
   val measureCompareTime = BenchMarkUtils.compareMeasure _
 
-  Util.regularExpression()
+
+  Util.taraiFunc()
+  // Util.regularExpression()
 
   /*
   Collection.sizeOrLength()

src/main/scala/Util.scala

@@ -1,3 +1,8 @@
+import cats.{Now, Eval}
+
+import cats.data._
+import cats.implicits._
+
 import services.BenchMarkUtils
 
 object Util {
@@ -26,4 +31,21 @@ object Util {
     measureCompareTime("findAllIn and positive after read", () => (0 to 100).foreach(_ => xsFunc()))("findPrefixOf ", () => (0 to 100).foreach((_ => ysFunc())))
   }
 
+  // たらい回し関数のチェック
+  def tarai(x: Int, y: Int, z: Int): Int =
+    if (x <= y) y else tarai(tarai(x - 1, y, z),
+      tarai(y - 1, z, x),
+      tarai(z - 1, x, y))
+
+  def taraiE(x: Eval[Int], y: Eval[Int], z: Eval[Int]): Eval[Int] =
+    (x, y).mapN(_ <= _) ifM (y, taraiE(taraiE(x.map(_ - 1), y, z),
+      taraiE(y.map(_ - 1), z, x),
+      taraiE(z.map(_ - 1), x, y)))
+
+  def taraiFunc(): Unit = {
+    // tarai(20, 10, 5)
+    measureCompareTime("tarai func ", () => tarai(20, 10, 5))("taraiE  ", () => taraiE(Now(20), Now(20), Now(5)).value )
+  }
+
+
 }