1 files changed, 28 insertions, 0 deletions
diff --git a/ext/wasm/sql/001-sudoku.sql b/ext/wasm/sql/001-sudoku.sql
new file mode 100644
index 0000000..53661b1
--- /dev/null
+++ b/ext/wasm/sql/001-sudoku.sql
@@ -0,0 +1,28 @@
+WITH RECURSIVE
+  input(sud) AS (
+    VALUES('53..7....6..195....98....6.8...6...34..8.3..17...2...6.6....28....419..5....8..79')
+  ),
+  digits(z, lp) AS (
+    VALUES('1', 1)
+    UNION ALL SELECT
+    CAST(lp+1 AS TEXT), lp+1 FROM digits WHERE lp<9
+  ),
+  x(s, ind) AS (
+    SELECT sud, instr(sud, '.') FROM input
+    UNION ALL
+    SELECT
+      substr(s, 1, ind-1) || z || substr(s, ind+1),
+      instr( substr(s, 1, ind-1) || z || substr(s, ind+1), '.' )
+     FROM x, digits AS z
+    WHERE ind>0
+      AND NOT EXISTS (
+            SELECT 1
+              FROM digits AS lp
+             WHERE z.z = substr(s, ((ind-1)/9)*9 + lp, 1)
+                OR z.z = substr(s, ((ind-1)%9) + (lp-1)*9 + 1, 1)
+                OR z.z = substr(s, (((ind-1)/3) % 3) * 3
+                        + ((ind-1)/27) * 27 + lp
+                        + ((lp-1) / 3) * 6, 1)
+         )
+  )
+SELECT s FROM x WHERE ind=0;