commit c1c84c992f549afe08b65856a30dea8eda0b8f92
Author: VyunSergey <vyun.sergey@icloud.com>
Date:   Thu Jun 10 13:50:37 2021 +0300

    Initial Commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7c94718
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,7 @@
+# Project exclude paths
+/.bsp
+/.idea
+/project/target/
+/project/project/target/
+/target/
+/target/scala-2.13/classes/
diff --git a/build.sbt b/build.sbt
new file mode 100644
index 0000000..997afab
--- /dev/null
+++ b/build.sbt
@@ -0,0 +1,5 @@
+name := "tinkoff-pr"
+
+version := "0.1"
+
+scalaVersion := "2.13.6"
diff --git a/project/build.properties b/project/build.properties
new file mode 100644
index 0000000..97a7ea7
--- /dev/null
+++ b/project/build.properties
@@ -0,0 +1 @@
+sbt.version = 1.4.7
\ No newline at end of file
diff --git a/src/main/scala/test1.scala b/src/main/scala/test1.scala
new file mode 100644
index 0000000..f012815
--- /dev/null
+++ b/src/main/scala/test1.scala
@@ -0,0 +1,31 @@
+object test1 extends App {
+  /**
+   *  1) Сжать последовательность целых чисел
+   *  Seq(1, 2, 2, 3, 4, 3, 3, 3) => Seq((1, 1), (2, 2), (3, 1), (4, 1), (3, 3))
+   *  Ответ выдать в виде Seq[(Int, Int)] (число из последовательности и число последовательных повторений)
+   *  2) восстановить исходную последовательность из сжатой
+   */
+
+  def collectP(seq: Seq[Int]): Seq[(Int, Int)] =
+    seq.foldLeft(Seq.empty[(Int, Int)]) {
+      case ((elm, cnt) :: tail, int) if elm == int =>
+        (int, cnt + 1) +: tail
+      case (acc, int) =>
+        (int, 1) +: acc
+      case (Nil, int) => Seq((int, 1))
+    }
+
+  def explodeP(seq: Seq[(Int, Int)]): Seq[Int] = {
+    seq.flatMap { case (i, cnt) => Seq.fill(cnt)(i) }
+  }
+
+  val seq = Seq(1, 2, 2, 3, 4, 3, 3, 3)
+  val res = collectP(seq).reverse
+  val res2 = explodeP(res)
+
+  println(res)
+  assert(res == Seq((1, 1), (2, 2), (3, 1), (4, 1), (3, 3)))
+
+  println(res2)
+  assert(res2 == seq)
+}
diff --git a/src/main/scala/test2.scala b/src/main/scala/test2.scala
new file mode 100644
index 0000000..d3af8a0
--- /dev/null
+++ b/src/main/scala/test2.scala
@@ -0,0 +1,53 @@
+import scala.concurrent.{Await, ExecutionContext, Future}
+import scala.concurrent.duration._
+import scala.util.control.NonFatal
+
+object test2 extends App {
+  /**
+   *  На входе получаем последовательность асинхронных вызовов
+   *  с сигнатурой Seq[Future[String]]
+   *  Получить Future[(Seq[String], Seq[Throwable]) - результат агрегации
+   *  выполненных Future и исключений
+   */
+  def sequenceF(seq: Seq[Future[String]])
+               (implicit ec: ExecutionContext): Future[(Seq[String], Seq[Throwable])] = {
+    Future.sequence(
+      seq.map { ftr =>
+        ftr.map(Right(_)).recover { case NonFatal(e) => Left(e) }
+      }
+    ).map { seq =>
+      seq.foldLeft((Seq.empty[String], Seq.empty[Throwable])) {
+        case ((res, errs), Left(e)) => (res, errs :+ e)
+        case ((res, errs), Right(str)) => (res :+ str, errs)
+      }
+    }
+  }
+
+  import scala.concurrent.ExecutionContext.Implicits.global
+
+  val (exp1, exp2, exp3) = (
+    new RuntimeException("exception1"),
+    new RuntimeException("exception2"),
+    new RuntimeException("exception3")
+  )
+  val talk = Seq(
+    Future {
+      Thread.sleep(1000)
+      "red"
+    },
+    Future.failed(exp1),
+    Future.successful("blue"),
+    Future.failed(exp2),
+    Future.successful("green"),
+    Future.failed(exp3)
+  )
+
+  val resF = sequenceF(talk)
+  val (res, errs) = Await.result(resF, 1.minute)
+
+  println(res)
+  assert(res == Seq("red", "blue", "green"))
+
+  println(errs)
+  assert(errs == Seq(exp1, exp2, exp3))
+}
diff --git a/src/main/scala/test3.scala b/src/main/scala/test3.scala
new file mode 100644
index 0000000..2a07643
--- /dev/null
+++ b/src/main/scala/test3.scala
@@ -0,0 +1,36 @@
+object test3 extends App {
+  /**
+   *  Transformation Chain
+   *  Дан набор возможных трансформаций: type Transformation[T] = T => Option[T]
+   *  Написать функцию преобразования последовательности трансформаций в возможную трансформацию.
+   *  Новая трансформация это результат работы всей цепочки трансформаций, которые не вернули None.
+   *  Если все вернули None, то общий результат None.
+   */
+
+  type Transformation[T] = T => Option[T]
+
+  def transformationChain[T](chain: Seq[Transformation[T]]): Transformation[T] =
+    (t: T) => {
+      chain.foldLeft(Option.empty[T]) { (acc, trm) =>
+        acc.flatMap { t =>
+          trm(t) match {
+            case s: Some[T] => s
+            case None => Some(t)
+          }
+        }.orElse(trm(t))
+      }
+    }
+
+  val t1: Transformation[Int] = t => Some(t + t)
+  val t2: Transformation[Int] = _ => None
+  val t3: Transformation[Int] = t => if(t > 2) Some(t * t) else None
+
+  val tc1 = transformationChain(Seq(t1,t2,t3))
+  val tc2 = transformationChain(Seq(t2,t3))
+
+  println(tc1(2), tc1(1), tc2(1))
+
+  assert(tc1(2).contains(16))
+  assert(tc1(1).contains(2))
+  assert(tc2(1).isEmpty)
+}