introduce bitloops

src/main/java/puzzle/Export.java

@@ -114,7 +114,6 @@ public record Export() {
          for (int i = 0, len = s.len(); i < len; i++) cells[i] = s.pos(i);
          
          char direction;
-         var  isReversed = false;
          var  startRow   = Grid.r(cells[0]);
          var  startCol   = Grid.c(cells[0]);
          if (d == 2) {              // right -> horizontal
@@ -123,10 +122,8 @@ public record Export() {
             direction = Placed.VERTICAL;
          } else if (d == 4) {       // left -> horizontal (REVERSED)
             direction  = Placed.HORIZONTAL;
-            isReversed = true;
          } else if (d == 1) {       // up -> vertical (REVERSED)
             direction  = Placed.VERTICAL;
-            isReversed = true;
          } else {
             return null;
          }
@@ -139,7 +136,7 @@ public record Export() {
                  s.clueR(),
                  s.clueC(),
                  cells,
-                 isReversed
+                 !s.increasing()
          );
       }
       public ExportedPuzzle exportFormatFromFilled(int difficulty, Rewards rewards) {