Data commit

Task/Perfect-shuffle/Scala/perfect-shuffle.scala

@@ -0,0 +1,24 @@
+object PerfectShuffle extends App {
+  private def sizes = Seq(8, 24, 52, 100, 1020, 1024, 10000)
+
+  private def perfectShuffle(size: Int): Int = {
+    require(size % 2 == 0, "Card deck must be even")
+
+    val (half, a) = (size / 2, Array.range(0, size))
+    val original = a.clone
+    var count = 1
+    while (true) {
+      val aa = a.clone
+      for (i <- 0 until half) {
+        a(2 * i) = aa(i)
+        a(2 * i + 1) = aa(i + half)
+      }
+      if (a.deep == original.deep) return count
+      count += 1
+    }
+    0
+  }
+
+  for (size <- sizes) println(f"$size%5d : ${perfectShuffle(size)}%5d")
+
+}