char *errors; /* size w*h: errors detected */
char *marks; /* size w*h: 'no line here' marks placed. */
int completed, used_solve;
- int loop_length; /* filled in by check_completion when complete. */
};
#define DEFAULT_PRESET 3
#define ERROR_CLUE 16
-static void dsf_update_completion(game_state *state, int *loopclass,
- int ax, int ay, char dir,
- int *dsf, int *dsfsize)
+static void dsf_update_completion(game_state *state, int ax, int ay, char dir,
+ int *dsf)
{
int w = state->shared->w /*, h = state->shared->h */;
- int ac = ay*w+ax, ae, bx, by, bc, be;
+ int ac = ay*w+ax, bx, by, bc;
if (!(state->lines[ac] & dir)) return; /* no link */
bx = ax + DX(dir); by = ay + DY(dir);
assert(state->lines[bc] & F(dir)); /* should have reciprocal link */
if (!(state->lines[bc] & F(dir))) return;
- ae = dsf_canonify(dsf, ac);
- be = dsf_canonify(dsf, bc);
-
- if (ae == be) { /* detected a loop! */
- if (*loopclass != -1) /* this is the second loop, doom. */
- return;
- *loopclass = ae;
- } else {
- int size = dsfsize[ae] + dsfsize[be];
- dsf_merge(dsf, ac, bc);
- ae = dsf_canonify(dsf, ac);
- dsfsize[ae] = size;
- }
- return;
+ dsf_merge(dsf, ac, bc);
}
static void check_completion(game_state *state, int mark)
{
int w = state->shared->w, h = state->shared->h, x, y, i, d;
- int had_error = FALSE /*, is_complete = FALSE */, loopclass;
- int *dsf, *dsfsize;
+ int had_error = FALSE;
+ int *dsf, *component_state;
+ int nsilly, nloop, npath, largest_comp, largest_size;
+ enum { COMP_NONE, COMP_LOOP, COMP_PATH, COMP_SILLY, COMP_EMPTY };
if (mark) {
for (i = 0; i < w*h; i++) {
#define ERROR(x,y,e) do { had_error = TRUE; if (mark) state->errors[(y)*w+(x)] |= (e); } while(0)
/*
- * First of all: we should have one single closed loop, passing through all clues.
+ * Analyse the solution into loops, paths and stranger things.
+ * Basic strategy here is all the same as in Loopy - see the big
+ * comment in loopy.c's check_completion() - and for exactly the
+ * same reasons, since Loopy and Pearl have basically the same
+ * form of expected solution.
*/
- dsf = snewn(w*h, int);
- dsfsize = snewn(w*h, int);
- dsf_init(dsf, w*h);
- for (i = 0; i < w*h; i++) dsfsize[i] = 1;
- loopclass = -1;
+ dsf = snew_dsf(w*h);
+ /* Build the dsf. */
for (x = 0; x < w; x++) {
for (y = 0; y < h; y++) {
- dsf_update_completion(state, &loopclass, x, y, R, dsf, dsfsize);
- dsf_update_completion(state, &loopclass, x, y, D, dsf, dsfsize);
+ dsf_update_completion(state, x, y, R, dsf);
+ dsf_update_completion(state, x, y, D, dsf);
}
}
- if (loopclass != -1) {
- /* We have a loop. Check all squares with lines on. */
- for (x = 0; x < w; x++) {
- for (y = 0; y < h; y++) {
- if (state->lines[y*w+x] == BLANK) {
- if (state->shared->clues[y*w+x] != NOCLUE) {
- /* the loop doesn't include this clue square! */
- ERROR(x, y, ERROR_CLUE);
- }
- } else {
- if (dsf_canonify(dsf, y*w+x) != loopclass) {
- /* these lines are not on the loop: mark them as error. */
- ERROR(x, y, state->lines[y*w+x]);
- }
- }
- }
- }
+
+ /* Initialise a state variable for each connected component. */
+ component_state = snewn(w*h, int);
+ for (i = 0; i < w*h; i++) {
+ if (dsf_canonify(dsf, i) == i)
+ component_state[i] = COMP_LOOP;
+ else
+ component_state[i] = COMP_NONE;
}
/*
- * Second: check no clues are contradicted.
+ * Classify components, and mark errors where a square has more
+ * than two line segments.
*/
-
for (x = 0; x < w; x++) {
for (y = 0; y < h; y++) {
int type = state->lines[y*w+x];
- /*
- * Check that no square has more than two line segments.
- */
- if (NBITS(type) > 2) {
+ int degree = NBITS(type);
+ int comp = dsf_canonify(dsf, y*w+x);
+ if (degree > 2) {
ERROR(x,y,type);
+ component_state[comp] = COMP_SILLY;
+ } else if (degree == 0) {
+ component_state[comp] = COMP_EMPTY;
+ } else if (degree == 1) {
+ if (component_state[comp] != COMP_SILLY)
+ component_state[comp] = COMP_PATH;
}
- /*
- * Check that no clues are contradicted. This code is similar to
- * the code that sets up the maximal clue array for any given
- * loop.
- */
+ }
+ }
+
+ /* Count the components, and find the largest sensible one. */
+ nsilly = nloop = npath = 0;
+ largest_comp = largest_size = -1;
+ for (i = 0; i < w*h; i++) {
+ if (component_state[i] == COMP_SILLY) {
+ nsilly++;
+ } else if (component_state[i] == COMP_PATH ||
+ component_state[i] == COMP_LOOP) {
+ int this_size;
+
+ if (component_state[i] == COMP_PATH)
+ npath++;
+ else if (component_state[i] == COMP_LOOP)
+ nloop++;
+
+ if ((this_size = dsf_size(dsf, i)) > largest_size) {
+ largest_comp = i;
+ largest_size = this_size;
+ }
+ }
+ }
+
+ if (nloop > 0 && nloop + npath > 1) {
+ /*
+ * If there are at least two sensible components including at
+ * least one loop, highlight every sensible component that is
+ * not the largest one.
+ */
+ for (i = 0; i < w*h; i++) {
+ int comp = dsf_canonify(dsf, i);
+ if ((component_state[comp] == COMP_LOOP ||
+ component_state[comp] == COMP_PATH) && comp != largest_comp)
+ ERROR(i%w, i/w, state->lines[i]);
+ }
+ }
+
+ /* Now we've finished with the dsf and component states. The only
+ * thing we'll need to remember later on is whether all edges were
+ * part of a single loop, for which our counter variables
+ * nsilly,nloop,npath are enough. */
+ sfree(component_state);
+ sfree(dsf);
+
+ /*
+ * Check that no clues are contradicted. This code is similar to
+ * the code that sets up the maximal clue array for any given
+ * loop.
+ */
+ for (x = 0; x < w; x++) {
+ for (y = 0; y < h; y++) {
+ int type = state->lines[y*w+x];
if (state->shared->clues[y*w+x] == CORNER) {
/* Supposed to be a corner: will find a contradiction if
* it actually contains a straight line, or if it touches any
}
}
}
- if (!had_error && loopclass != -1) {
- state->completed = TRUE;
- state->loop_length = dsfsize[loopclass];
- }
- sfree(dsf);
- sfree(dsfsize);
+ if (nloop == 1 && nsilly == 0 && npath == 0) {
+ /*
+ * If there's exactly one loop (so that the puzzle is at least
+ * potentially complete), we need to ensure it hasn't left any
+ * clue out completely.
+ */
+ for (x = 0; x < w; x++) {
+ for (y = 0; y < h; y++) {
+ if (state->lines[y*w+x] == BLANK) {
+ if (state->shared->clues[y*w+x] != NOCLUE) {
+ /* the loop doesn't include this clue square! */
+ ERROR(x, y, ERROR_CLUE);
+ }
+ }
+ }
+ }
- return;
+ /*
+ * But if not, then we're done!
+ */
+ if (!had_error)
+ state->completed = TRUE;
+ }
}
/* completion check:
~ian / sgt-puzzles.git / commitdiff