Data commit

Task/Monty-Hall-problem/Scala/monty-hall-problem.scala

@@ -0,0 +1,33 @@
+import scala.util.Random
+
+object MontyHallSimulation {
+  def main(args: Array[String]) {
+    val samples = if (args.size == 1 && (args(0) matches "\\d+")) args(0).toInt else 1000
+    val doors = Set(0, 1, 2)
+    var stayStrategyWins = 0
+    var switchStrategyWins = 0
+
+    1 to samples foreach { _ =>
+      val prizeDoor = Random shuffle doors head;
+      val choosenDoor = Random shuffle doors head;
+      val hostDoor = Random shuffle (doors - choosenDoor - prizeDoor) head;
+      val switchDoor = doors - choosenDoor - hostDoor head;
+
+      (choosenDoor, switchDoor) match {
+        case (`prizeDoor`, _) => stayStrategyWins += 1
+        case (_, `prizeDoor`) => switchStrategyWins += 1
+      }
+    }
+
+    def percent(n: Int) = n * 100 / samples
+
+    val report = """|%d simulations were ran.
+                    |Staying won %d times (%d %%)
+                    |Switching won %d times (%d %%)""".stripMargin
+
+    println(report
+            format (samples,
+                    stayStrategyWins, percent(stayStrategyWins),
+                    switchStrategyWins, percent(switchStrategyWins)))
+  }
+}