int verbose = FALSE;
#endif
-static void do_recurse(unsigned char *known, unsigned char *deduced,
- unsigned char *row, int *data, int len,
+static int do_recurse(unsigned char *known, unsigned char *deduced,
+ unsigned char *row,
+ unsigned char *minpos_done, unsigned char *maxpos_done,
+ unsigned char *minpos_ok, unsigned char *maxpos_ok,
+ int *data, int len,
int freespace, int ndone, int lowest)
{
int i, j, k;
+
+ /* This algorithm basically tries all possible ways the given rows of
+ * black blocks can be laid out in the row/column being examined.
+ * Special care is taken to avoid checking the tail of a row/column
+ * if the same conditions have already been checked during this recursion
+ * The algorithm also takes care to cut its losses as soon as an
+ * invalid (partial) solution is detected.
+ */
if (data[ndone]) {
+ if (lowest >= minpos_done[ndone] && lowest <= maxpos_done[ndone]) {
+ if (lowest >= minpos_ok[ndone] && lowest <= maxpos_ok[ndone]) {
+ for (i=0; i<lowest; i++)
+ deduced[i] |= row[i];
+ }
+ return lowest >= minpos_ok[ndone] && lowest <= maxpos_ok[ndone];
+ } else {
+ if (lowest < minpos_done[ndone]) minpos_done[ndone] = lowest;
+ if (lowest > maxpos_done[ndone]) maxpos_done[ndone] = lowest;
+ }
for (i=0; i<=freespace; i++) {
j = lowest;
- for (k=0; k<i; k++) row[j++] = DOT;
- for (k=0; k<data[ndone]; k++) row[j++] = BLOCK;
- if (j < len) row[j++] = DOT;
- do_recurse(known, deduced, row, data, len,
- freespace-i, ndone+1, j);
+ for (k=0; k<i; k++) {
+ if (known[j] == BLOCK) goto next_iter;
+ row[j++] = DOT;
+ }
+ for (k=0; k<data[ndone]; k++) {
+ if (known[j] == DOT) goto next_iter;
+ row[j++] = BLOCK;
+ }
+ if (j < len) {
+ if (known[j] == BLOCK) goto next_iter;
+ row[j++] = DOT;
+ }
+ if (do_recurse(known, deduced, row, minpos_done, maxpos_done,
+ minpos_ok, maxpos_ok, data, len, freespace-i, ndone+1, j)) {
+ if (lowest < minpos_ok[ndone]) minpos_ok[ndone] = lowest;
+ if (lowest + i > maxpos_ok[ndone]) maxpos_ok[ndone] = lowest + i;
+ if (lowest + i > maxpos_done[ndone]) maxpos_done[ndone] = lowest + i;
+ }
+ next_iter:
+ j++;
}
+ return lowest >= minpos_ok[ndone] && lowest <= maxpos_ok[ndone];
} else {
- for (i=lowest; i<len; i++)
+ for (i=lowest; i<len; i++) {
+ if (known[i] == BLOCK) return FALSE;
row[i] = DOT;
- for (i=0; i<len; i++)
- if (known[i] && known[i] != row[i])
- return;
+ }
for (i=0; i<len; i++)
deduced[i] |= row[i];
+ return TRUE;
}
}
+
static int do_row(unsigned char *known, unsigned char *deduced,
unsigned char *row,
- unsigned char *start, int len, int step, int *data
+ unsigned char *minpos_done, unsigned char *maxpos_done,
+ unsigned char *minpos_ok, unsigned char *maxpos_ok,
+ unsigned char *start, int len, int step, int *data,
+ unsigned int *changed
#ifdef STANDALONE_SOLVER
, const char *rowcol, int index, int cluewid
#endif
int rowlen, i, freespace, done_any;
freespace = len+1;
- for (rowlen = 0; data[rowlen]; rowlen++)
+ for (rowlen = 0; data[rowlen]; rowlen++) {
+ minpos_done[rowlen] = minpos_ok[rowlen] = len - 1;
+ maxpos_done[rowlen] = maxpos_ok[rowlen] = 0;
freespace -= data[rowlen]+1;
+ }
for (i = 0; i < len; i++) {
known[i] = start[i*step];
deduced[i] = 0;
}
+ for (i = len - 1; i >= 0 && known[i] == DOT; i--)
+ freespace--;
+
+ do_recurse(known, deduced, row, minpos_done, maxpos_done, minpos_ok, maxpos_ok, data, len, freespace, 0, 0);
- do_recurse(known, deduced, row, data, len, freespace, 0, 0);
done_any = FALSE;
for (i=0; i<len; i++)
if (deduced[i] && deduced[i] != STILL_UNKNOWN && !known[i]) {
start[i*step] = deduced[i];
+ if (changed) changed[i]++;
done_any = TRUE;
}
#ifdef STANDALONE_SOLVER
return done_any;
}
+static int solve_puzzle(game_state *state, unsigned char *grid, int w, int h,
+ unsigned char *matrix, unsigned char *workspace,
+ unsigned int *changed_h, unsigned int *changed_w,
+ int *rowdata
+#ifdef STANDALONE_SOLVER
+ , int cluewid
+#else
+ , int dummy
+#endif
+ )
+{
+ int i, j, ok, max;
+ int max_h, max_w;
+
+ assert((state!=NULL) ^ (grid!=NULL));
+
+ max = max(w, h);
+
+ memset(matrix, 0, w*h);
+
+ /* For each column, compute how many squares can be deduced
+ * from just the row-data.
+ * Later, changed_* will hold how many squares were changed
+ * in every row/column in the previous iteration
+ * Changed_* is used to choose the next rows / cols to re-examine
+ */
+ for (i=0; i<h; i++) {
+ int freespace;
+ if (state) {
+ memcpy(rowdata, state->rowdata + state->rowsize*(w+i), max*sizeof(int));
+ rowdata[state->rowlen[w+i]] = 0;
+ } else {
+ rowdata[compute_rowdata(rowdata, grid+i*w, w, 1)] = 0;
+ }
+ for (j=0, freespace=w+1; rowdata[j]; j++) freespace -= rowdata[j] + 1;
+ for (j=0, changed_h[i]=0; rowdata[j]; j++)
+ if (rowdata[j] > freespace)
+ changed_h[i] += rowdata[j] - freespace;
+ }
+ for (i=0,max_h=0; i<h; i++)
+ if (changed_h[i] > max_h)
+ max_h = changed_h[i];
+ for (i=0; i<w; i++) {
+ int freespace;
+ if (state) {
+ memcpy(rowdata, state->rowdata + state->rowsize*i, max*sizeof(int));
+ rowdata[state->rowlen[i]] = 0;
+ } else {
+ rowdata[compute_rowdata(rowdata, grid+i, h, w)] = 0;
+ }
+ for (j=0, freespace=h+1; rowdata[j]; j++) freespace -= rowdata[j] + 1;
+ for (j=0, changed_w[i]=0; rowdata[j]; j++)
+ if (rowdata[j] > freespace)
+ changed_w[i] += rowdata[j] - freespace;
+ }
+ for (i=0,max_w=0; i<w; i++)
+ if (changed_w[i] > max_w)
+ max_w = changed_w[i];
+
+ /* Solve the puzzle.
+ * Process rows/columns individually. Deductions involving more than one
+ * row and/or column at a time are not supported.
+ * Take care to only process rows/columns which have been changed since they
+ * were previously processed.
+ * Also, prioritize rows/columns which have had the most changes since their
+ * previous processing, as they promise the greatest benefit.
+ * Extremely rectangular grids (e.g. 10x20, 15x40, etc.) are not treated specially.
+ */
+ do {
+ for (; max_h && max_h >= max_w; max_h--) {
+ for (i=0; i<h; i++) {
+ if (changed_h[i] >= max_h) {
+ if (state) {
+ memcpy(rowdata, state->rowdata + state->rowsize*(w+i), max*sizeof(int));
+ rowdata[state->rowlen[w+i]] = 0;
+ } else {
+ rowdata[compute_rowdata(rowdata, grid+i*w, w, 1)] = 0;
+ }
+ do_row(workspace, workspace+max, workspace+2*max,
+ workspace+3*max, workspace+4*max,
+ workspace+5*max, workspace+6*max,
+ matrix+i*w, w, 1, rowdata, changed_w
+#ifdef STANDALONE_SOLVER
+ , "row", i+1, cluewid
+#endif
+ );
+ changed_h[i] = 0;
+ }
+ }
+ for (i=0,max_w=0; i<w; i++)
+ if (changed_w[i] > max_w)
+ max_w = changed_w[i];
+ }
+ for (; max_w && max_w >= max_h; max_w--) {
+ for (i=0; i<w; i++) {
+ if (changed_w[i] >= max_w) {
+ if (state) {
+ memcpy(rowdata, state->rowdata + state->rowsize*i, max*sizeof(int));
+ rowdata[state->rowlen[i]] = 0;
+ } else {
+ rowdata[compute_rowdata(rowdata, grid+i, h, w)] = 0;
+ }
+ do_row(workspace, workspace+max, workspace+2*max,
+ workspace+3*max, workspace+4*max,
+ workspace+5*max, workspace+6*max,
+ matrix+i, h, w, rowdata, changed_h
+#ifdef STANDALONE_SOLVER
+ , "col", i+1, cluewid
+#endif
+ );
+ changed_w[i] = 0;
+ }
+ }
+ for (i=0,max_h=0; i<h; i++)
+ if (changed_h[i] > max_h)
+ max_h = changed_h[i];
+ }
+ } while (max_h>0 || max_w>0);
+
+ ok = TRUE;
+ for (i=0; i<h; i++) {
+ for (j=0; j<w; j++) {
+ if (matrix[i*w+j] == UNKNOWN)
+ ok = FALSE;
+ }
+ }
+
+ return ok;
+}
+
static unsigned char *generate_soluble(random_state *rs, int w, int h)
{
- int i, j, done_any, ok, ntries, max;
+ int i, j, ok, ntries, max;
unsigned char *grid, *matrix, *workspace;
+ unsigned int *changed_h, *changed_w;
int *rowdata;
+ max = max(w, h);
+
grid = snewn(w*h, unsigned char);
+ /* Allocate this here, to avoid having to reallocate it again for every geneerated grid */
matrix = snewn(w*h, unsigned char);
- max = max(w, h);
- workspace = snewn(max*3, unsigned char);
+ workspace = snewn(max*7, unsigned char);
+ changed_h = snewn(max+1, unsigned int);
+ changed_w = snewn(max+1, unsigned int);
rowdata = snewn(max+1, int);
ntries = 0;
if (!ok)
continue;
- memset(matrix, 0, w*h);
-
- do {
- done_any = 0;
- for (i=0; i<h; i++) {
- rowdata[compute_rowdata(rowdata, grid+i*w, w, 1)] = 0;
- done_any |= do_row(workspace, workspace+max, workspace+2*max,
- matrix+i*w, w, 1, rowdata
-#ifdef STANDALONE_SOLVER
- , NULL, 0, 0 /* never do diagnostics here */
-#endif
- );
- }
- for (i=0; i<w; i++) {
- rowdata[compute_rowdata(rowdata, grid+i, h, w)] = 0;
- done_any |= do_row(workspace, workspace+max, workspace+2*max,
- matrix+i, h, w, rowdata
-#ifdef STANDALONE_SOLVER
- , NULL, 0, 0 /* never do diagnostics here */
-#endif
- );
- }
- } while (done_any);
-
- ok = TRUE;
- for (i=0; i<h; i++) {
- for (j=0; j<w; j++) {
- if (matrix[i*w+j] == UNKNOWN)
- ok = FALSE;
- }
- }
+ ok = solve_puzzle(NULL, grid, w, h, matrix, workspace,
+ changed_h, changed_w, rowdata, 0);
} while (!ok);
sfree(matrix);
sfree(workspace);
+ sfree(changed_h);
+ sfree(changed_w);
sfree(rowdata);
return grid;
}
int w = state->w, h = state->h;
int i;
char *ret;
- int done_any, max;
+ int max, ok;
unsigned char *workspace;
+ unsigned int *changed_h, *changed_w;
int *rowdata;
/*
if (ai)
return dupstr(ai);
- matrix = snewn(w*h, unsigned char);
max = max(w, h);
- workspace = snewn(max*3, unsigned char);
+ matrix = snewn(w*h, unsigned char);
+ workspace = snewn(max*7, unsigned char);
+ changed_h = snewn(max+1, unsigned int);
+ changed_w = snewn(max+1, unsigned int);
rowdata = snewn(max+1, int);
- memset(matrix, 0, w*h);
-
- do {
- done_any = 0;
- for (i=0; i<h; i++) {
- memcpy(rowdata, state->rowdata + state->rowsize*(w+i),
- max*sizeof(int));
- rowdata[state->rowlen[w+i]] = 0;
- done_any |= do_row(workspace, workspace+max, workspace+2*max,
- matrix+i*w, w, 1, rowdata
-#ifdef STANDALONE_SOLVER
- , NULL, 0, 0 /* never do diagnostics here */
-#endif
- );
- }
- for (i=0; i<w; i++) {
- memcpy(rowdata, state->rowdata + state->rowsize*i, max*sizeof(int));
- rowdata[state->rowlen[i]] = 0;
- done_any |= do_row(workspace, workspace+max, workspace+2*max,
- matrix+i, h, w, rowdata
-#ifdef STANDALONE_SOLVER
- , NULL, 0, 0 /* never do diagnostics here */
-#endif
- );
- }
- } while (done_any);
+ ok = solve_puzzle(state, NULL, w, h, matrix, workspace,
+ changed_h, changed_w, rowdata, 0);
sfree(workspace);
+ sfree(changed_h);
+ sfree(changed_w);
sfree(rowdata);
- for (i = 0; i < w*h; i++) {
- if (matrix[i] != BLOCK && matrix[i] != DOT) {
- sfree(matrix);
- *error = "Solving algorithm cannot complete this puzzle";
- return NULL;
- }
+ if (!ok) {
+ sfree(matrix);
+ *error = "Solving algorithm cannot complete this puzzle";
+ return NULL;
}
ret = snewn(w*h+2, char);
s = new_game(NULL, p, desc);
{
- int w = p->w, h = p->h, i, j, done_any, max, cluewid = 0;
+ int w = p->w, h = p->h, i, j, max, cluewid = 0;
unsigned char *matrix, *workspace;
+ unsigned int *changed_h, *changed_w;
int *rowdata;
matrix = snewn(w*h, unsigned char);
max = max(w, h);
- workspace = snewn(max*3, unsigned char);
+ workspace = snewn(max*7, unsigned char);
+ changed_h = snewn(max+1, unsigned int);
+ changed_w = snewn(max+1, unsigned int);
rowdata = snewn(max+1, int);
- memset(matrix, 0, w*h);
-
if (verbose) {
int thiswid;
/*
}
}
- do {
- done_any = 0;
- for (i=0; i<h; i++) {
- memcpy(rowdata, s->rowdata + s->rowsize*(w+i),
- max*sizeof(int));
- rowdata[s->rowlen[w+i]] = 0;
- done_any |= do_row(workspace, workspace+max, workspace+2*max,
- matrix+i*w, w, 1, rowdata
-#ifdef STANDALONE_SOLVER
- , "row", i+1, cluewid
-#endif
- );
- }
- for (i=0; i<w; i++) {
- memcpy(rowdata, s->rowdata + s->rowsize*i, max*sizeof(int));
- rowdata[s->rowlen[i]] = 0;
- done_any |= do_row(workspace, workspace+max, workspace+2*max,
- matrix+i, h, w, rowdata
-#ifdef STANDALONE_SOLVER
- , "col", i+1, cluewid
-#endif
- );
- }
- } while (done_any);
+ solve_puzzle(s, NULL, w, h, matrix, workspace,
+ changed_h, changed_w, rowdata, cluewid);
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
~ian / sgt-puzzles.git / commitdiff