From bcad930bfc6f55eb8184ca091dfe1cdcdc987c0b Mon Sep 17 00:00:00 2001
From: mike <michael@appmodel.nl>
Date: Wed, 14 Jan 2026 07:50:35 +0100
Subject: [PATCH] introduce bitloops

---
 src/main/java/puzzle/Export.java               |  1 -
 src/main/java/puzzle/SwedishGenerator.java     | 14 +++++++-------
 src/test/java/puzzle/SwedishGeneratorTest.java |  6 +++---
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/src/main/java/puzzle/Export.java b/src/main/java/puzzle/Export.java
index bd62b73..c4cc77e 100644
--- a/src/main/java/puzzle/Export.java
+++ b/src/main/java/puzzle/Export.java
@@ -120,7 +120,6 @@ public record Export() {
       }
       public String renderHuman() {
          return String.join("\n", exportGrid(_ -> ' ', '#'));
-         
       }
       public boolean notClue(int c) { return grid.notClue(c); }
       @FunctionalInterface
diff --git a/src/main/java/puzzle/SwedishGenerator.java b/src/main/java/puzzle/SwedishGenerator.java
index 8da9f42..f8986bc 100644
--- a/src/main/java/puzzle/SwedishGenerator.java
+++ b/src/main/java/puzzle/SwedishGenerator.java
@@ -263,11 +263,11 @@ public record SwedishGenerator(Rng rng, int[] stack, Clues cache) {
          var grid = new Grid(new byte[SIZE], lo, hi);
          for (var l = lo; l != X; l &= l - 1) {
             int idx = Long.numberOfTrailingZeros(l);
-            grid.g[idx] = digitAt(idx);
+            grid.setLetter(idx, digitAt(idx));
          }
          for (var h = hi; h != X; h &= h - 1) {
             int idx = 64 | Long.numberOfTrailingZeros(h);
-            grid.g[idx] = digitAt(idx);
+            grid.setLetter(idx, digitAt(idx));
          }
          return grid;
       }
@@ -293,6 +293,7 @@ public record SwedishGenerator(Rng rng, int[] stack, Clues cache) {
       public static int r(int offset)  { return offset & 7; }
       public static int c(int offset)  { return offset >>> 3; }
       static int offset(int r, int c)  { return r | (c << 3); }
+      /// the pos will never target a clue
       public byte letter32At(int pos)  { return g[pos]; }
       void setLetter(int idx, byte ch) { g[idx] = ch; }
       void clearletter(int idx)        { g[idx] = DASH; }
@@ -842,7 +843,7 @@ public record SwedishGenerator(Rng rng, int[] stack, Clues cache) {
    }
    
    static int[] candidateInfoForPattern(long[] res, long pattern, long[][] posBitsets, int numLongs) {
-      boolean first    = true;
+      boolean first = true;
       
       for (long p = pattern; p != 0; ) {
          int combined = (int) (p & 0xFF);
@@ -877,9 +878,8 @@ public record SwedishGenerator(Rng rng, int[] stack, Clues cache) {
       return indices;
    }
    
-   static int candidateCountForPattern(final long[] res, final long pattern, final DictEntry entry, final int numLongs) {
-      val     posBitsets = entry.posBitsets;
-      boolean first      = true;
+   static int candidateCountForPattern(final long[] res, final long pattern, final long[][] posBitsets, final int numLongs) {
+      boolean first = true;
       
       for (long p = pattern; p != 0; ) {
          int combined = (int) (p & 0xFF);
@@ -963,7 +963,7 @@ public record SwedishGenerator(Rng rng, int[] stack, Clues cache) {
                if (assigned[s.key] != X) continue;
                var pattern = patternForSlot(grid, s);
                var index   = dictIndex[s.length()];
-               count = pattern == X ? index.length : candidateCountForPattern(bitset, pattern, index, index.numlong);
+               count = pattern == X ? index.length : candidateCountForPattern(bitset, pattern, index.posBitsets, index.numlong);
                
                if (count == 0) {
                   current = PICK_NOT_DONE;
diff --git a/src/test/java/puzzle/SwedishGeneratorTest.java b/src/test/java/puzzle/SwedishGeneratorTest.java
index 212bea0..5e4e998 100644
--- a/src/test/java/puzzle/SwedishGeneratorTest.java
+++ b/src/test/java/puzzle/SwedishGeneratorTest.java
@@ -409,13 +409,13 @@ public class SwedishGeneratorTest {
       
       var ctx     = Context.get();
       var pattern = packPattern("APP");
-      assertEquals(2, candidateCountForPattern(ctx.bitset(), pattern, entry5, entry5.numlong()));
+      assertEquals(2, candidateCountForPattern(ctx.bitset(), pattern, entry5.posBitsets(), entry5.numlong()));
       
       pattern = packPattern("BAN");
-      assertEquals(1, candidateCountForPattern(ctx.bitset(), pattern, entry5, entry5.numlong()));
+      assertEquals(1, candidateCountForPattern(ctx.bitset(), pattern, entry5.posBitsets(), entry5.numlong()));
       
       pattern = packPattern("CAT");
-      assertEquals(0, candidateCountForPattern(ctx.bitset(), pattern, entry5, entry5.numlong()));
+      assertEquals(0, candidateCountForPattern(ctx.bitset(), pattern, entry5.posBitsets(), entry5.numlong()));
    }
    
    @Test