X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=palisade.c;h=b9d578d0f7f05e1f55c61b95c52f231c86f5c5d4;hb=db313b3948d27244dd7c34c2609c66d6204d8931;hp=f7b379128505d5fa0a6d5c01efa391e4d1b226f6;hpb=d60e348aae16e718e1e7cc2b6e090956eb7e4b52;p=sgt-puzzles.git

diff --git a/palisade.c b/palisade.c
index f7b3791..b9d578d 100644
--- a/palisade.c
+++ b/palisade.c
@@ -511,10 +511,20 @@ static void dfs_dsf(int i, int w, borderflag *border, int *dsf, int black)
 static int is_solved(const game_params *params, clue *clues,
                      borderflag *border)
 {
-    int wh = params->w * params->h, k = params->k, *dsf = snew_dsf(wh), i;
+    int w = params->w, h = params->h, wh = w*h, k = params->k;
+    int i, x, y;
+    int *dsf = snew_dsf(wh);
 
     assert (dsf[0] == UNVISITED); /* check: UNVISITED and dsf.c match up */
 
+    /*
+     * A game is solved if:
+     *
+     *  - the borders drawn on the grid divide it into connected
+     *    components such that every square is in a component of the
+     *    correct size
+     *  - the borders also satisfy the clue set
+     */
     for (i = 0; i < wh; ++i) {
         if (dsf[i] == UNVISITED) dfs_dsf(i, params->w, border, dsf, TRUE);
         if (dsf_size(dsf, i) != k) goto error;
@@ -522,6 +532,26 @@ static int is_solved(const game_params *params, clue *clues,
         if (clues[i] != bitcount[border[i] & BORDER_MASK]) goto error;
     }
 
+    /*
+     * ... and thirdly:
+     *
+     *  - there are no *stray* borders, in that every border is
+     *    actually part of the division between two components.
+     *    Otherwise you could cheat by finding a subdivision which did
+     *    not *exceed* any clue square's counter, and then adding a
+     *    few extra edges.
+     */
+    for (y = 0; y < h; y++) {
+        for (x = 0; x < w; x++) {
+            if (x+1 < w && (border[y*w+x] & BORDER_R) &&
+                dsf_canonify(dsf, y*w+x) == dsf_canonify(dsf, y*w+(x+1)))
+                goto error;
+            if (y+1 < h && (border[y*w+x] & BORDER_D) &&
+                dsf_canonify(dsf, y*w+x) == dsf_canonify(dsf, (y+1)*w+x))
+                goto error;
+        }
+    }
+
     sfree(dsf);
     return TRUE;
 
@@ -667,17 +697,17 @@ static char *validate_desc(const game_params *params, const char *desc)
     int w = params->w, h = params->h, wh = w*h, squares = 0;
 
     for (/* nop */; *desc; ++desc) {
-        if (islower(*desc)) {
+        if (islower((unsigned char)*desc)) {
             squares += *desc - 'a' + 1;
-        } else if (isdigit(*desc)) {
+        } else if (isdigit((unsigned char)*desc)) {
             if (*desc > '4') {
                 static char buf[] = "Invalid (too large) number: '5'";
-                assert (isdigit(buf[lenof(buf) - 3]));
+                assert (isdigit((unsigned char)buf[lenof(buf) - 3]));
                 buf[lenof(buf) - 3] = *desc; /* ... or 6, 7, 8, 9 :-) */
                 return buf;
             }
             ++squares;
-        } else if (isprint(*desc)) {
+        } else if (isprint((unsigned char)*desc)) {
             static char buf[] = "Invalid character in data: '?'";
             buf[lenof(buf) - 3] = *desc;
             return buf;
@@ -702,8 +732,8 @@ static game_state *new_game(midend *me, const game_params *params,
 
     setmem(state->shared->clues, EMPTY, wh);
     for (i = 0; *desc; ++desc) {
-        if (isdigit(*desc)) state->shared->clues[i++] = *desc - '0';
-        else if (isalpha(*desc)) i += *desc - 'a' + 1;
+        if (isdigit((unsigned char)*desc)) state->shared->clues[i++] = *desc - '0';
+        else if (isalpha((unsigned char)*desc)) i += *desc - 'a' + 1;
     }
 
     snewa(state->borders, wh);
@@ -1317,7 +1347,7 @@ static void game_print(drawing *dr, const game_state *state, int tilesize)
 const struct game thegame = {
     "Palisade", "games.palisade", "palisade",
     default_params,
-    game_fetch_preset,
+    game_fetch_preset, NULL,
     decode_params,
     encode_params,
     free_params,