introduce bitloops

src/main/java/puzzle/Main.java

@@ -413,7 +413,7 @@ public class Main {
       if (mask == null) return null;
       val multiThreaded = Thread.currentThread().getName().contains("pool");
       var slots         = Masker.extractSlots(mask, dict.index());
-      val slotInfo      = Masker.scoreSlots(new int[slots.length], slots);
+      val slotInfo      = Masker.scoreSlots(slots);
       var grid          = mask.toGrid();
       var filled        = fillMask(rng, slotInfo, grid, multiThreaded);