X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=singles.c;h=5fe054c6638ecdc2fa1a19a09b42742ed09b08f4;hb=a0a581c8b5422bf0c5ed3fde6aa25811e4eb89fc;hp=2aa9a69b7cf82ce8d4a328f218e73811a320fa02;hpb=251b21c41813055d9c416378508b1ee038bc3dac;p=sgt-puzzles.git

diff --git a/singles.c b/singles.c
index 2aa9a69..5fe054c 100644
--- a/singles.c
+++ b/singles.c
@@ -535,16 +535,28 @@ static int check_complete(game_state *state, unsigned flags)
     for (y = 0; y < h; y++) /* check rows from (0,y) */
         error += check_rowcol(state, y*w, 1, w, flags);
 
-    /* mark (all) white regions as an error if there is more than one.
-     * may want to make this less in-your-face (by only marking
-     * the smallest region as an error, for example -- but what if we
-     * have two regions of identical size?) */
-    for (i = 0; i < state->n; i++) {
-        if (!(state->flags[i] & F_BLACK) &&
-            dsf_size(dsf, i) < nwhite) {
-            error += 1;
-            if (flags & CC_MARK_ERRORS)
-                state->flags[i] |= F_ERROR;
+    /* If there's more than one white region, pick the largest one to
+     * be the canonical one (arbitrarily tie-breaking towards lower
+     * array indices), and mark all the others as erroneous. */
+    {
+        int largest = 0, canonical = -1;
+        for (i = 0; i < state->n; i++)
+            if (!(state->flags[i] & F_BLACK)) {
+                int size = dsf_size(dsf, i);
+                if (largest < size) {
+                    largest = size;
+                    canonical = i;
+                }
+            }
+
+        if (largest < nwhite) {
+            for (i = 0; i < state->n; i++)
+                if (!(state->flags[i] & F_BLACK) &&
+                    dsf_canonify(dsf, i) != canonical) {
+                    error += 1;
+                    if (flags & CC_MARK_ERRORS)
+                        state->flags[i] |= F_ERROR;
+                }
         }
     }
 
@@ -1802,7 +1814,7 @@ static void game_print(drawing *dr, const game_state *state, int tilesize)
 const struct game thegame = {
     "Singles", "games.singles", "singles",
     default_params,
-    game_fetch_preset,
+    game_fetch_preset, NULL,
     decode_params,
     encode_params,
     free_params,