X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/puzzles/blobdiff_plain/9003c6f7c564e586cd118034069ec3cd1546cc15..2e215ca91f5ba292166531b57c0ecddf10b1f8f7:/solo.c

diff --git a/solo.c b/solo.c
index 766adde..43abc1f 100644
--- a/solo.c
+++ b/solo.c
@@ -1473,7 +1473,7 @@ static int solver_killer_sums(struct solver_usage *usage, int b,
     }
     assert(nsquares > 0);
 
-    if (nsquares > 4)
+    if (nsquares < 2 || nsquares > 4)
 	return 0;
 
     if (!cage_is_region) {
@@ -1773,9 +1773,16 @@ static void solver(int cr, struct block_structure *blocks,
      * Place all the clue numbers we are given.
      */
     for (x = 0; x < cr; x++)
-	for (y = 0; y < cr; y++)
-	    if (grid[y*cr+x])
+	for (y = 0; y < cr; y++) {
+            int n = grid[y*cr+x];
+	    if (n) {
+                if (!cube(x,y,n)) {
+                    diff = DIFF_IMPOSSIBLE;
+                    goto got_result;
+                }
 		solver_place(usage, x, y, grid[y*cr+x]);
+            }
+        }
 
     /*
      * Now loop over the grid repeatedly trying all permitted modes
@@ -2041,7 +2048,7 @@ static void solver(int cr, struct block_structure *blocks,
 					     );
 		if (ret > 0) {
 		    changed = TRUE;
-		    kdiff = max(kdiff, DIFF_KINTERSECT);
+		    kdiff = max(kdiff, DIFF_KSUMS);
 		} else if (ret < 0) {
 		    diff = DIFF_IMPOSSIBLE;
 		    goto got_result;