| 1 | /* |
| 2 | * slant.c: Puzzle from nikoli.co.jp involving drawing a diagonal |
| 3 | * line through each square of a grid. |
| 4 | */ |
| 5 | |
| 6 | /* |
| 7 | * In this puzzle you have a grid of squares, each of which must |
| 8 | * contain a diagonal line; you also have clue numbers placed at |
| 9 | * _points_ of that grid, which means there's a (w+1) x (h+1) array |
| 10 | * of possible clue positions. |
| 11 | * |
| 12 | * I'm therefore going to adopt a rigid convention throughout this |
| 13 | * source file of using w and h for the dimensions of the grid of |
| 14 | * squares, and W and H for the dimensions of the grid of points. |
| 15 | * Thus, W == w+1 and H == h+1 always. |
| 16 | * |
| 17 | * Clue arrays will be W*H `signed char's, and the clue at each |
| 18 | * point will be a number from 0 to 4, or -1 if there's no clue. |
| 19 | * |
| 20 | * Solution arrays will be W*H `signed char's, and the number at |
| 21 | * each point will be +1 for a forward slash (/), -1 for a |
| 22 | * backslash (\), and 0 for unknown. |
| 23 | */ |
| 24 | |
| 25 | #include <stdio.h> |
| 26 | #include <stdlib.h> |
| 27 | #include <string.h> |
| 28 | #include <assert.h> |
| 29 | #include <ctype.h> |
| 30 | #include <math.h> |
| 31 | |
| 32 | #include "puzzles.h" |
| 33 | |
| 34 | enum { |
| 35 | COL_BACKGROUND, |
| 36 | COL_GRID, |
| 37 | COL_INK, |
| 38 | COL_SLANT1, |
| 39 | COL_SLANT2, |
| 40 | COL_ERROR, |
| 41 | NCOLOURS |
| 42 | }; |
| 43 | |
| 44 | /* |
| 45 | * In standalone solver mode, `verbose' is a variable which can be |
| 46 | * set by command-line option; in debugging mode it's simply always |
| 47 | * true. |
| 48 | */ |
| 49 | #if defined STANDALONE_SOLVER |
| 50 | #define SOLVER_DIAGNOSTICS |
| 51 | int verbose = FALSE; |
| 52 | #elif defined SOLVER_DIAGNOSTICS |
| 53 | #define verbose TRUE |
| 54 | #endif |
| 55 | |
| 56 | /* |
| 57 | * Difficulty levels. I do some macro ickery here to ensure that my |
| 58 | * enum and the various forms of my name list always match up. |
| 59 | */ |
| 60 | #define DIFFLIST(A) \ |
| 61 | A(EASY,Easy,e) \ |
| 62 | A(HARD,Hard,h) |
| 63 | #define ENUM(upper,title,lower) DIFF_ ## upper, |
| 64 | #define TITLE(upper,title,lower) #title, |
| 65 | #define ENCODE(upper,title,lower) #lower |
| 66 | #define CONFIG(upper,title,lower) ":" #title |
| 67 | enum { DIFFLIST(ENUM) DIFFCOUNT }; |
| 68 | static char const *const slant_diffnames[] = { DIFFLIST(TITLE) }; |
| 69 | static char const slant_diffchars[] = DIFFLIST(ENCODE); |
| 70 | #define DIFFCONFIG DIFFLIST(CONFIG) |
| 71 | |
| 72 | struct game_params { |
| 73 | int w, h, diff; |
| 74 | }; |
| 75 | |
| 76 | typedef struct game_clues { |
| 77 | int w, h; |
| 78 | signed char *clues; |
| 79 | int *tmpdsf; |
| 80 | int refcount; |
| 81 | } game_clues; |
| 82 | |
| 83 | #define ERR_VERTEX 1 |
| 84 | #define ERR_SQUARE 2 |
| 85 | #define ERR_SQUARE_TMP 4 |
| 86 | |
| 87 | struct game_state { |
| 88 | struct game_params p; |
| 89 | game_clues *clues; |
| 90 | signed char *soln; |
| 91 | unsigned char *errors; |
| 92 | int completed; |
| 93 | int used_solve; /* used to suppress completion flash */ |
| 94 | }; |
| 95 | |
| 96 | static game_params *default_params(void) |
| 97 | { |
| 98 | game_params *ret = snew(game_params); |
| 99 | |
| 100 | ret->w = ret->h = 8; |
| 101 | ret->diff = DIFF_EASY; |
| 102 | |
| 103 | return ret; |
| 104 | } |
| 105 | |
| 106 | static const struct game_params slant_presets[] = { |
| 107 | {5, 5, DIFF_EASY}, |
| 108 | {5, 5, DIFF_HARD}, |
| 109 | {8, 8, DIFF_EASY}, |
| 110 | {8, 8, DIFF_HARD}, |
| 111 | {12, 10, DIFF_EASY}, |
| 112 | {12, 10, DIFF_HARD}, |
| 113 | }; |
| 114 | |
| 115 | static int game_fetch_preset(int i, char **name, game_params **params) |
| 116 | { |
| 117 | game_params *ret; |
| 118 | char str[80]; |
| 119 | |
| 120 | if (i < 0 || i >= lenof(slant_presets)) |
| 121 | return FALSE; |
| 122 | |
| 123 | ret = snew(game_params); |
| 124 | *ret = slant_presets[i]; |
| 125 | |
| 126 | sprintf(str, "%dx%d %s", ret->w, ret->h, slant_diffnames[ret->diff]); |
| 127 | |
| 128 | *name = dupstr(str); |
| 129 | *params = ret; |
| 130 | return TRUE; |
| 131 | } |
| 132 | |
| 133 | static void free_params(game_params *params) |
| 134 | { |
| 135 | sfree(params); |
| 136 | } |
| 137 | |
| 138 | static game_params *dup_params(game_params *params) |
| 139 | { |
| 140 | game_params *ret = snew(game_params); |
| 141 | *ret = *params; /* structure copy */ |
| 142 | return ret; |
| 143 | } |
| 144 | |
| 145 | static void decode_params(game_params *ret, char const *string) |
| 146 | { |
| 147 | ret->w = ret->h = atoi(string); |
| 148 | while (*string && isdigit((unsigned char)*string)) string++; |
| 149 | if (*string == 'x') { |
| 150 | string++; |
| 151 | ret->h = atoi(string); |
| 152 | while (*string && isdigit((unsigned char)*string)) string++; |
| 153 | } |
| 154 | if (*string == 'd') { |
| 155 | int i; |
| 156 | string++; |
| 157 | for (i = 0; i < DIFFCOUNT; i++) |
| 158 | if (*string == slant_diffchars[i]) |
| 159 | ret->diff = i; |
| 160 | if (*string) string++; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | static char *encode_params(game_params *params, int full) |
| 165 | { |
| 166 | char data[256]; |
| 167 | |
| 168 | sprintf(data, "%dx%d", params->w, params->h); |
| 169 | if (full) |
| 170 | sprintf(data + strlen(data), "d%c", slant_diffchars[params->diff]); |
| 171 | |
| 172 | return dupstr(data); |
| 173 | } |
| 174 | |
| 175 | static config_item *game_configure(game_params *params) |
| 176 | { |
| 177 | config_item *ret; |
| 178 | char buf[80]; |
| 179 | |
| 180 | ret = snewn(4, config_item); |
| 181 | |
| 182 | ret[0].name = "Width"; |
| 183 | ret[0].type = C_STRING; |
| 184 | sprintf(buf, "%d", params->w); |
| 185 | ret[0].sval = dupstr(buf); |
| 186 | ret[0].ival = 0; |
| 187 | |
| 188 | ret[1].name = "Height"; |
| 189 | ret[1].type = C_STRING; |
| 190 | sprintf(buf, "%d", params->h); |
| 191 | ret[1].sval = dupstr(buf); |
| 192 | ret[1].ival = 0; |
| 193 | |
| 194 | ret[2].name = "Difficulty"; |
| 195 | ret[2].type = C_CHOICES; |
| 196 | ret[2].sval = DIFFCONFIG; |
| 197 | ret[2].ival = params->diff; |
| 198 | |
| 199 | ret[3].name = NULL; |
| 200 | ret[3].type = C_END; |
| 201 | ret[3].sval = NULL; |
| 202 | ret[3].ival = 0; |
| 203 | |
| 204 | return ret; |
| 205 | } |
| 206 | |
| 207 | static game_params *custom_params(config_item *cfg) |
| 208 | { |
| 209 | game_params *ret = snew(game_params); |
| 210 | |
| 211 | ret->w = atoi(cfg[0].sval); |
| 212 | ret->h = atoi(cfg[1].sval); |
| 213 | ret->diff = cfg[2].ival; |
| 214 | |
| 215 | return ret; |
| 216 | } |
| 217 | |
| 218 | static char *validate_params(game_params *params, int full) |
| 219 | { |
| 220 | /* |
| 221 | * (At least at the time of writing this comment) The grid |
| 222 | * generator is actually capable of handling even zero grid |
| 223 | * dimensions without crashing. Puzzles with a zero-area grid |
| 224 | * are a bit boring, though, because they're already solved :-) |
| 225 | * And puzzles with a dimension of 1 can't be made Hard, which |
| 226 | * means the simplest thing is to forbid them altogether. |
| 227 | */ |
| 228 | |
| 229 | if (params->w < 2 || params->h < 2) |
| 230 | return "Width and height must both be at least two"; |
| 231 | |
| 232 | return NULL; |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * Scratch space for solver. |
| 237 | */ |
| 238 | struct solver_scratch { |
| 239 | /* |
| 240 | * Disjoint set forest which tracks the connected sets of |
| 241 | * points. |
| 242 | */ |
| 243 | int *connected; |
| 244 | |
| 245 | /* |
| 246 | * Counts the number of possible exits from each connected set |
| 247 | * of points. (That is, the number of possible _simultaneous_ |
| 248 | * exits: an unconnected point labelled 2 has an exit count of |
| 249 | * 2 even if all four possible edges are still under |
| 250 | * consideration.) |
| 251 | */ |
| 252 | int *exits; |
| 253 | |
| 254 | /* |
| 255 | * Tracks whether each connected set of points includes a |
| 256 | * border point. |
| 257 | */ |
| 258 | unsigned char *border; |
| 259 | |
| 260 | /* |
| 261 | * Another disjoint set forest. This one tracks _squares_ which |
| 262 | * are known to slant in the same direction. |
| 263 | */ |
| 264 | int *equiv; |
| 265 | |
| 266 | /* |
| 267 | * Stores slash values which we know for an equivalence class. |
| 268 | * When we fill in a square, we set slashval[canonify(x)] to |
| 269 | * the same value as soln[x], so that we can then spot other |
| 270 | * squares equivalent to it and fill them in immediately via |
| 271 | * their known equivalence. |
| 272 | */ |
| 273 | signed char *slashval; |
| 274 | |
| 275 | /* |
| 276 | * Useful to have this information automatically passed to |
| 277 | * solver subroutines. (This pointer is not dynamically |
| 278 | * allocated by new_scratch and free_scratch.) |
| 279 | */ |
| 280 | const signed char *clues; |
| 281 | }; |
| 282 | |
| 283 | static struct solver_scratch *new_scratch(int w, int h) |
| 284 | { |
| 285 | int W = w+1, H = h+1; |
| 286 | struct solver_scratch *ret = snew(struct solver_scratch); |
| 287 | ret->connected = snewn(W*H, int); |
| 288 | ret->exits = snewn(W*H, int); |
| 289 | ret->border = snewn(W*H, unsigned char); |
| 290 | ret->equiv = snewn(w*h, int); |
| 291 | ret->slashval = snewn(w*h, signed char); |
| 292 | return ret; |
| 293 | } |
| 294 | |
| 295 | static void free_scratch(struct solver_scratch *sc) |
| 296 | { |
| 297 | sfree(sc->slashval); |
| 298 | sfree(sc->equiv); |
| 299 | sfree(sc->border); |
| 300 | sfree(sc->exits); |
| 301 | sfree(sc->connected); |
| 302 | sfree(sc); |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * Wrapper on dsf_merge() which updates the `exits' and `border' |
| 307 | * arrays. |
| 308 | */ |
| 309 | static void merge_vertices(int *connected, |
| 310 | struct solver_scratch *sc, int i, int j) |
| 311 | { |
| 312 | int exits = -1, border = FALSE; /* initialise to placate optimiser */ |
| 313 | |
| 314 | if (sc) { |
| 315 | i = dsf_canonify(connected, i); |
| 316 | j = dsf_canonify(connected, j); |
| 317 | |
| 318 | /* |
| 319 | * We have used one possible exit from each of the two |
| 320 | * classes. Thus, the viable exit count of the new class is |
| 321 | * the sum of the old exit counts minus two. |
| 322 | */ |
| 323 | exits = sc->exits[i] + sc->exits[j] - 2; |
| 324 | |
| 325 | border = sc->border[i] || sc->border[j]; |
| 326 | } |
| 327 | |
| 328 | dsf_merge(connected, i, j); |
| 329 | |
| 330 | if (sc) { |
| 331 | i = dsf_canonify(connected, i); |
| 332 | sc->exits[i] = exits; |
| 333 | sc->border[i] = border; |
| 334 | } |
| 335 | } |
| 336 | |
| 337 | /* |
| 338 | * Called when we have just blocked one way out of a particular |
| 339 | * point. If that point is a non-clue point (thus has a variable |
| 340 | * number of exits), we have therefore decreased its potential exit |
| 341 | * count, so we must decrement the exit count for the group as a |
| 342 | * whole. |
| 343 | */ |
| 344 | static void decr_exits(struct solver_scratch *sc, int i) |
| 345 | { |
| 346 | if (sc->clues[i] < 0) { |
| 347 | i = dsf_canonify(sc->connected, i); |
| 348 | sc->exits[i]--; |
| 349 | } |
| 350 | } |
| 351 | |
| 352 | static void fill_square(int w, int h, int x, int y, int v, |
| 353 | signed char *soln, |
| 354 | int *connected, struct solver_scratch *sc) |
| 355 | { |
| 356 | int W = w+1 /*, H = h+1 */; |
| 357 | |
| 358 | assert(x >= 0 && x < w && y >= 0 && y < h); |
| 359 | |
| 360 | if (soln[y*w+x] != 0) { |
| 361 | return; /* do nothing */ |
| 362 | } |
| 363 | |
| 364 | #ifdef SOLVER_DIAGNOSTICS |
| 365 | if (verbose) |
| 366 | printf(" placing %c in %d,%d\n", v == -1 ? '\\' : '/', x, y); |
| 367 | #endif |
| 368 | |
| 369 | soln[y*w+x] = v; |
| 370 | |
| 371 | if (sc) { |
| 372 | int c = dsf_canonify(sc->equiv, y*w+x); |
| 373 | sc->slashval[c] = v; |
| 374 | } |
| 375 | |
| 376 | if (v < 0) { |
| 377 | merge_vertices(connected, sc, y*W+x, (y+1)*W+(x+1)); |
| 378 | if (sc) { |
| 379 | decr_exits(sc, y*W+(x+1)); |
| 380 | decr_exits(sc, (y+1)*W+x); |
| 381 | } |
| 382 | } else { |
| 383 | merge_vertices(connected, sc, y*W+(x+1), (y+1)*W+x); |
| 384 | if (sc) { |
| 385 | decr_exits(sc, y*W+x); |
| 386 | decr_exits(sc, (y+1)*W+(x+1)); |
| 387 | } |
| 388 | } |
| 389 | } |
| 390 | |
| 391 | /* |
| 392 | * Solver. Returns 0 for impossibility, 1 for success, 2 for |
| 393 | * ambiguity or failure to converge. |
| 394 | */ |
| 395 | static int slant_solve(int w, int h, const signed char *clues, |
| 396 | signed char *soln, struct solver_scratch *sc, |
| 397 | int difficulty) |
| 398 | { |
| 399 | int W = w+1, H = h+1; |
| 400 | int x, y, i, j; |
| 401 | int done_something; |
| 402 | |
| 403 | /* |
| 404 | * Clear the output. |
| 405 | */ |
| 406 | memset(soln, 0, w*h); |
| 407 | |
| 408 | sc->clues = clues; |
| 409 | |
| 410 | /* |
| 411 | * Establish a disjoint set forest for tracking connectedness |
| 412 | * between grid points. |
| 413 | */ |
| 414 | for (i = 0; i < W*H; i++) |
| 415 | sc->connected[i] = i; /* initially all distinct */ |
| 416 | |
| 417 | /* |
| 418 | * Establish a disjoint set forest for tracking which squares |
| 419 | * are known to slant in the same direction. |
| 420 | */ |
| 421 | for (i = 0; i < w*h; i++) |
| 422 | sc->equiv[i] = i; /* initially all distinct */ |
| 423 | |
| 424 | /* |
| 425 | * Clear the slashval array. |
| 426 | */ |
| 427 | memset(sc->slashval, 0, w*h); |
| 428 | |
| 429 | /* |
| 430 | * Initialise the `exits' and `border' arrays. Theses is used |
| 431 | * to do second-order loop avoidance: the dual of the no loops |
| 432 | * constraint is that every point must be somehow connected to |
| 433 | * the border of the grid (otherwise there would be a solid |
| 434 | * loop around it which prevented this). |
| 435 | * |
| 436 | * I define a `dead end' to be a connected group of points |
| 437 | * which contains no border point, and which can form at most |
| 438 | * one new connection outside itself. Then I forbid placing an |
| 439 | * edge so that it connects together two dead-end groups, since |
| 440 | * this would yield a non-border-connected isolated subgraph |
| 441 | * with no further scope to extend it. |
| 442 | */ |
| 443 | for (y = 0; y < H; y++) |
| 444 | for (x = 0; x < W; x++) { |
| 445 | if (y == 0 || y == H-1 || x == 0 || x == W-1) |
| 446 | sc->border[y*W+x] = TRUE; |
| 447 | else |
| 448 | sc->border[y*W+x] = FALSE; |
| 449 | |
| 450 | if (clues[y*W+x] < 0) |
| 451 | sc->exits[y*W+x] = 4; |
| 452 | else |
| 453 | sc->exits[y*W+x] = clues[y*W+x]; |
| 454 | } |
| 455 | |
| 456 | /* |
| 457 | * Make a one-off preliminary pass over the grid looking for |
| 458 | * starting-point arrangements. The ones we need to spot are: |
| 459 | * |
| 460 | * - two adjacent 1s in the centre of the grid imply that each |
| 461 | * one's single line points towards the other. (If either 1 |
| 462 | * were connected on the far side, the two squares shared |
| 463 | * between the 1s would both link to the other 1 as a |
| 464 | * consequence of neither linking to the first.) Thus, we |
| 465 | * can fill in the four squares around them. |
| 466 | * |
| 467 | * - dually, two adjacent 3s imply that each one's _non_-line |
| 468 | * points towards the other. |
| 469 | * |
| 470 | * - if the pair of 1s and 3s is not _adjacent_ but is |
| 471 | * separated by one or more 2s, the reasoning still applies. |
| 472 | * |
| 473 | * This is more advanced than just spotting obvious starting |
| 474 | * squares such as central 4s and edge 2s, so we disable it on |
| 475 | * DIFF_EASY. |
| 476 | * |
| 477 | * (I don't like this loop; it feels grubby to me. My |
| 478 | * mathematical intuition feels there ought to be some more |
| 479 | * general deductive form which contains this loop as a special |
| 480 | * case, but I can't bring it to mind right now.) |
| 481 | */ |
| 482 | if (difficulty > DIFF_EASY) { |
| 483 | for (y = 1; y+1 < H; y++) |
| 484 | for (x = 1; x+1 < W; x++) { |
| 485 | int v = clues[y*W+x], s, x2, y2, dx, dy; |
| 486 | if (v != 1 && v != 3) |
| 487 | continue; |
| 488 | /* Slash value of the square up and left of (x,y). */ |
| 489 | s = (v == 1 ? +1 : -1); |
| 490 | |
| 491 | /* Look in each direction once. */ |
| 492 | for (dy = 0; dy < 2; dy++) { |
| 493 | dx = 1 - dy; |
| 494 | x2 = x+dx; |
| 495 | y2 = y+dy; |
| 496 | if (x2+1 >= W || y2+1 >= H) |
| 497 | continue; /* too close to the border */ |
| 498 | while (x2+dx+1 < W && y2+dy+1 < H && clues[y2*W+x2] == 2) |
| 499 | x2 += dx, y2 += dy; |
| 500 | if (clues[y2*W+x2] == v) { |
| 501 | #ifdef SOLVER_DIAGNOSTICS |
| 502 | if (verbose) |
| 503 | printf("found adjacent %ds at %d,%d and %d,%d\n", |
| 504 | v, x, y, x2, y2); |
| 505 | #endif |
| 506 | fill_square(w, h, x-1, y-1, s, soln, |
| 507 | sc->connected, sc); |
| 508 | fill_square(w, h, x-1+dy, y-1+dx, -s, soln, |
| 509 | sc->connected, sc); |
| 510 | fill_square(w, h, x2, y2, s, soln, |
| 511 | sc->connected, sc); |
| 512 | fill_square(w, h, x2-dy, y2-dx, -s, soln, |
| 513 | sc->connected, sc); |
| 514 | } |
| 515 | } |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | /* |
| 520 | * Repeatedly try to deduce something until we can't. |
| 521 | */ |
| 522 | do { |
| 523 | done_something = FALSE; |
| 524 | |
| 525 | /* |
| 526 | * Any clue point with the number of remaining lines equal |
| 527 | * to zero or to the number of remaining undecided |
| 528 | * neighbouring squares can be filled in completely. |
| 529 | */ |
| 530 | for (y = 0; y < H; y++) |
| 531 | for (x = 0; x < W; x++) { |
| 532 | struct { |
| 533 | int pos, slash; |
| 534 | } neighbours[4]; |
| 535 | int nneighbours; |
| 536 | int nu, nl, c, s, eq, eq2, last, meq, mj1, mj2; |
| 537 | |
| 538 | if ((c = clues[y*W+x]) < 0) |
| 539 | continue; |
| 540 | |
| 541 | /* |
| 542 | * We have a clue point. Start by listing its |
| 543 | * neighbouring squares, in order around the point, |
| 544 | * together with the type of slash that would be |
| 545 | * required in that square to connect to the point. |
| 546 | */ |
| 547 | nneighbours = 0; |
| 548 | if (x > 0 && y > 0) { |
| 549 | neighbours[nneighbours].pos = (y-1)*w+(x-1); |
| 550 | neighbours[nneighbours].slash = -1; |
| 551 | nneighbours++; |
| 552 | } |
| 553 | if (x > 0 && y < h) { |
| 554 | neighbours[nneighbours].pos = y*w+(x-1); |
| 555 | neighbours[nneighbours].slash = +1; |
| 556 | nneighbours++; |
| 557 | } |
| 558 | if (x < w && y < h) { |
| 559 | neighbours[nneighbours].pos = y*w+x; |
| 560 | neighbours[nneighbours].slash = -1; |
| 561 | nneighbours++; |
| 562 | } |
| 563 | if (x < w && y > 0) { |
| 564 | neighbours[nneighbours].pos = (y-1)*w+x; |
| 565 | neighbours[nneighbours].slash = +1; |
| 566 | nneighbours++; |
| 567 | } |
| 568 | |
| 569 | /* |
| 570 | * Count up the number of undecided neighbours, and |
| 571 | * also the number of lines already present. |
| 572 | * |
| 573 | * If we're not on DIFF_EASY, then in this loop we |
| 574 | * also track whether we've seen two adjacent empty |
| 575 | * squares belonging to the same equivalence class |
| 576 | * (meaning they have the same type of slash). If |
| 577 | * so, we count them jointly as one line. |
| 578 | */ |
| 579 | nu = 0; |
| 580 | nl = c; |
| 581 | last = neighbours[nneighbours-1].pos; |
| 582 | if (soln[last] == 0) |
| 583 | eq = dsf_canonify(sc->equiv, last); |
| 584 | else |
| 585 | eq = -1; |
| 586 | meq = mj1 = mj2 = -1; |
| 587 | for (i = 0; i < nneighbours; i++) { |
| 588 | j = neighbours[i].pos; |
| 589 | s = neighbours[i].slash; |
| 590 | if (soln[j] == 0) { |
| 591 | nu++; /* undecided */ |
| 592 | if (meq < 0 && difficulty > DIFF_EASY) { |
| 593 | eq2 = dsf_canonify(sc->equiv, j); |
| 594 | if (eq == eq2 && last != j) { |
| 595 | /* |
| 596 | * We've found an equivalent pair. |
| 597 | * Mark it. This also inhibits any |
| 598 | * further equivalence tracking |
| 599 | * around this square, since we can |
| 600 | * only handle one pair (and in |
| 601 | * particular we want to avoid |
| 602 | * being misled by two overlapping |
| 603 | * equivalence pairs). |
| 604 | */ |
| 605 | meq = eq; |
| 606 | mj1 = last; |
| 607 | mj2 = j; |
| 608 | nl--; /* count one line */ |
| 609 | nu -= 2; /* and lose two undecideds */ |
| 610 | } else |
| 611 | eq = eq2; |
| 612 | } |
| 613 | } else { |
| 614 | eq = -1; |
| 615 | if (soln[j] == s) |
| 616 | nl--; /* here's a line */ |
| 617 | } |
| 618 | last = j; |
| 619 | } |
| 620 | |
| 621 | /* |
| 622 | * Check the counts. |
| 623 | */ |
| 624 | if (nl < 0 || nl > nu) { |
| 625 | /* |
| 626 | * No consistent value for this at all! |
| 627 | */ |
| 628 | #ifdef SOLVER_DIAGNOSTICS |
| 629 | if (verbose) |
| 630 | printf("need %d / %d lines around clue point at %d,%d!\n", |
| 631 | nl, nu, x, y); |
| 632 | #endif |
| 633 | return 0; /* impossible */ |
| 634 | } |
| 635 | |
| 636 | if (nu > 0 && (nl == 0 || nl == nu)) { |
| 637 | #ifdef SOLVER_DIAGNOSTICS |
| 638 | if (verbose) { |
| 639 | if (meq >= 0) |
| 640 | printf("partially (since %d,%d == %d,%d) ", |
| 641 | mj1%w, mj1/w, mj2%w, mj2/w); |
| 642 | printf("%s around clue point at %d,%d\n", |
| 643 | nl ? "filling" : "emptying", x, y); |
| 644 | } |
| 645 | #endif |
| 646 | for (i = 0; i < nneighbours; i++) { |
| 647 | j = neighbours[i].pos; |
| 648 | s = neighbours[i].slash; |
| 649 | if (soln[j] == 0 && j != mj1 && j != mj2) |
| 650 | fill_square(w, h, j%w, j/w, (nl ? s : -s), soln, |
| 651 | sc->connected, sc); |
| 652 | } |
| 653 | |
| 654 | done_something = TRUE; |
| 655 | } else if (nu == 2 && nl == 1 && difficulty > DIFF_EASY) { |
| 656 | /* |
| 657 | * If we have precisely two undecided squares |
| 658 | * and precisely one line to place between |
| 659 | * them, _and_ those squares are adjacent, then |
| 660 | * we can mark them as equivalent to one |
| 661 | * another. |
| 662 | * |
| 663 | * This even applies if meq >= 0: if we have a |
| 664 | * 2 clue point and two of its neighbours are |
| 665 | * already marked equivalent, we can indeed |
| 666 | * mark the other two as equivalent. |
| 667 | * |
| 668 | * We don't bother with this on DIFF_EASY, |
| 669 | * since we wouldn't have used the results |
| 670 | * anyway. |
| 671 | */ |
| 672 | last = -1; |
| 673 | for (i = 0; i < nneighbours; i++) { |
| 674 | j = neighbours[i].pos; |
| 675 | if (soln[j] == 0 && j != mj1 && j != mj2) { |
| 676 | if (last < 0) |
| 677 | last = i; |
| 678 | else if (last == i-1 || (last == 0 && i == 3)) |
| 679 | break; /* found a pair */ |
| 680 | } |
| 681 | } |
| 682 | if (i < nneighbours) { |
| 683 | int sv1, sv2; |
| 684 | |
| 685 | assert(last >= 0); |
| 686 | /* |
| 687 | * neighbours[last] and neighbours[i] are |
| 688 | * the pair. Mark them equivalent. |
| 689 | */ |
| 690 | #ifdef SOLVER_DIAGNOSTICS |
| 691 | if (verbose) { |
| 692 | if (meq >= 0) |
| 693 | printf("since %d,%d == %d,%d, ", |
| 694 | mj1%w, mj1/w, mj2%w, mj2/w); |
| 695 | } |
| 696 | #endif |
| 697 | mj1 = neighbours[last].pos; |
| 698 | mj2 = neighbours[i].pos; |
| 699 | #ifdef SOLVER_DIAGNOSTICS |
| 700 | if (verbose) |
| 701 | printf("clue point at %d,%d implies %d,%d == %d," |
| 702 | "%d\n", x, y, mj1%w, mj1/w, mj2%w, mj2/w); |
| 703 | #endif |
| 704 | mj1 = dsf_canonify(sc->equiv, mj1); |
| 705 | sv1 = sc->slashval[mj1]; |
| 706 | mj2 = dsf_canonify(sc->equiv, mj2); |
| 707 | sv2 = sc->slashval[mj2]; |
| 708 | if (sv1 != 0 && sv2 != 0 && sv1 != sv2) { |
| 709 | #ifdef SOLVER_DIAGNOSTICS |
| 710 | if (verbose) |
| 711 | printf("merged two equivalence classes with" |
| 712 | " different slash values!\n"); |
| 713 | #endif |
| 714 | return 0; |
| 715 | } |
| 716 | sv1 = sv1 ? sv1 : sv2; |
| 717 | dsf_merge(sc->equiv, mj1, mj2); |
| 718 | mj1 = dsf_canonify(sc->equiv, mj1); |
| 719 | sc->slashval[mj1] = sv1; |
| 720 | } |
| 721 | } |
| 722 | } |
| 723 | |
| 724 | if (done_something) |
| 725 | continue; |
| 726 | |
| 727 | /* |
| 728 | * Failing that, we now apply the second condition, which |
| 729 | * is that no square may be filled in such a way as to form |
| 730 | * a loop. Also in this loop (since it's over squares |
| 731 | * rather than points), we check slashval to see if we've |
| 732 | * already filled in another square in the same equivalence |
| 733 | * class. |
| 734 | * |
| 735 | * The slashval check is disabled on DIFF_EASY, as is dead |
| 736 | * end avoidance. Only _immediate_ loop avoidance remains. |
| 737 | */ |
| 738 | for (y = 0; y < h; y++) |
| 739 | for (x = 0; x < w; x++) { |
| 740 | int fs, bs, v; |
| 741 | int c1, c2; |
| 742 | #ifdef SOLVER_DIAGNOSTICS |
| 743 | char *reason = "<internal error>"; |
| 744 | #endif |
| 745 | |
| 746 | if (soln[y*w+x]) |
| 747 | continue; /* got this one already */ |
| 748 | |
| 749 | fs = FALSE; |
| 750 | bs = FALSE; |
| 751 | |
| 752 | if (difficulty > DIFF_EASY) |
| 753 | v = sc->slashval[dsf_canonify(sc->equiv, y*w+x)]; |
| 754 | else |
| 755 | v = 0; |
| 756 | |
| 757 | /* |
| 758 | * Try to rule out connectivity between (x,y) and |
| 759 | * (x+1,y+1); if successful, we will deduce that we |
| 760 | * must have a forward slash. |
| 761 | */ |
| 762 | c1 = dsf_canonify(sc->connected, y*W+x); |
| 763 | c2 = dsf_canonify(sc->connected, (y+1)*W+(x+1)); |
| 764 | if (c1 == c2) { |
| 765 | fs = TRUE; |
| 766 | #ifdef SOLVER_DIAGNOSTICS |
| 767 | reason = "simple loop avoidance"; |
| 768 | #endif |
| 769 | } |
| 770 | if (difficulty > DIFF_EASY && |
| 771 | !sc->border[c1] && !sc->border[c2] && |
| 772 | sc->exits[c1] <= 1 && sc->exits[c2] <= 1) { |
| 773 | fs = TRUE; |
| 774 | #ifdef SOLVER_DIAGNOSTICS |
| 775 | reason = "dead end avoidance"; |
| 776 | #endif |
| 777 | } |
| 778 | if (v == +1) { |
| 779 | fs = TRUE; |
| 780 | #ifdef SOLVER_DIAGNOSTICS |
| 781 | reason = "equivalence to an already filled square"; |
| 782 | #endif |
| 783 | } |
| 784 | |
| 785 | /* |
| 786 | * Now do the same between (x+1,y) and (x,y+1), to |
| 787 | * see if we are required to have a backslash. |
| 788 | */ |
| 789 | c1 = dsf_canonify(sc->connected, y*W+(x+1)); |
| 790 | c2 = dsf_canonify(sc->connected, (y+1)*W+x); |
| 791 | if (c1 == c2) { |
| 792 | bs = TRUE; |
| 793 | #ifdef SOLVER_DIAGNOSTICS |
| 794 | reason = "simple loop avoidance"; |
| 795 | #endif |
| 796 | } |
| 797 | if (difficulty > DIFF_EASY && |
| 798 | !sc->border[c1] && !sc->border[c2] && |
| 799 | sc->exits[c1] <= 1 && sc->exits[c2] <= 1) { |
| 800 | bs = TRUE; |
| 801 | #ifdef SOLVER_DIAGNOSTICS |
| 802 | reason = "dead end avoidance"; |
| 803 | #endif |
| 804 | } |
| 805 | if (v == -1) { |
| 806 | bs = TRUE; |
| 807 | #ifdef SOLVER_DIAGNOSTICS |
| 808 | reason = "equivalence to an already filled square"; |
| 809 | #endif |
| 810 | } |
| 811 | |
| 812 | if (fs && bs) { |
| 813 | /* |
| 814 | * No consistent value for this at all! |
| 815 | */ |
| 816 | #ifdef SOLVER_DIAGNOSTICS |
| 817 | if (verbose) |
| 818 | printf("%d,%d has no consistent slash!\n", x, y); |
| 819 | #endif |
| 820 | return 0; /* impossible */ |
| 821 | } |
| 822 | |
| 823 | if (fs) { |
| 824 | #ifdef SOLVER_DIAGNOSTICS |
| 825 | if (verbose) |
| 826 | printf("employing %s\n", reason); |
| 827 | #endif |
| 828 | fill_square(w, h, x, y, +1, soln, sc->connected, sc); |
| 829 | done_something = TRUE; |
| 830 | } else if (bs) { |
| 831 | #ifdef SOLVER_DIAGNOSTICS |
| 832 | if (verbose) |
| 833 | printf("employing %s\n", reason); |
| 834 | #endif |
| 835 | fill_square(w, h, x, y, -1, soln, sc->connected, sc); |
| 836 | done_something = TRUE; |
| 837 | } |
| 838 | } |
| 839 | |
| 840 | } while (done_something); |
| 841 | |
| 842 | /* |
| 843 | * Solver can make no more progress. See if the grid is full. |
| 844 | */ |
| 845 | for (i = 0; i < w*h; i++) |
| 846 | if (!soln[i]) |
| 847 | return 2; /* failed to converge */ |
| 848 | return 1; /* success */ |
| 849 | } |
| 850 | |
| 851 | /* |
| 852 | * Filled-grid generator. |
| 853 | */ |
| 854 | static void slant_generate(int w, int h, signed char *soln, random_state *rs) |
| 855 | { |
| 856 | int W = w+1, H = h+1; |
| 857 | int x, y, i; |
| 858 | int *connected, *indices; |
| 859 | |
| 860 | /* |
| 861 | * Clear the output. |
| 862 | */ |
| 863 | memset(soln, 0, w*h); |
| 864 | |
| 865 | /* |
| 866 | * Establish a disjoint set forest for tracking connectedness |
| 867 | * between grid points. |
| 868 | */ |
| 869 | connected = snewn(W*H, int); |
| 870 | for (i = 0; i < W*H; i++) |
| 871 | connected[i] = i; /* initially all distinct */ |
| 872 | |
| 873 | /* |
| 874 | * Prepare a list of the squares in the grid, and fill them in |
| 875 | * in a random order. |
| 876 | */ |
| 877 | indices = snewn(w*h, int); |
| 878 | for (i = 0; i < w*h; i++) |
| 879 | indices[i] = i; |
| 880 | shuffle(indices, w*h, sizeof(*indices), rs); |
| 881 | |
| 882 | /* |
| 883 | * Fill in each one in turn. |
| 884 | */ |
| 885 | for (i = 0; i < w*h; i++) { |
| 886 | int fs, bs, v; |
| 887 | |
| 888 | y = indices[i] / w; |
| 889 | x = indices[i] % w; |
| 890 | |
| 891 | fs = (dsf_canonify(connected, y*W+x) == |
| 892 | dsf_canonify(connected, (y+1)*W+(x+1))); |
| 893 | bs = (dsf_canonify(connected, (y+1)*W+x) == |
| 894 | dsf_canonify(connected, y*W+(x+1))); |
| 895 | |
| 896 | /* |
| 897 | * It isn't possible to get into a situation where we |
| 898 | * aren't allowed to place _either_ type of slash in a |
| 899 | * square. Thus, filled-grid generation never has to |
| 900 | * backtrack. |
| 901 | * |
| 902 | * Proof (thanks to Gareth Taylor): |
| 903 | * |
| 904 | * If it were possible, it would have to be because there |
| 905 | * was an existing path (not using this square) between the |
| 906 | * top-left and bottom-right corners of this square, and |
| 907 | * another between the other two. These two paths would |
| 908 | * have to cross at some point. |
| 909 | * |
| 910 | * Obviously they can't cross in the middle of a square, so |
| 911 | * they must cross by sharing a point in common. But this |
| 912 | * isn't possible either: if you chessboard-colour all the |
| 913 | * points on the grid, you find that any continuous |
| 914 | * diagonal path is entirely composed of points of the same |
| 915 | * colour. And one of our two hypothetical paths is between |
| 916 | * two black points, and the other is between two white |
| 917 | * points - therefore they can have no point in common. [] |
| 918 | */ |
| 919 | assert(!(fs && bs)); |
| 920 | |
| 921 | v = fs ? +1 : bs ? -1 : 2 * random_upto(rs, 2) - 1; |
| 922 | fill_square(w, h, x, y, v, soln, connected, NULL); |
| 923 | } |
| 924 | |
| 925 | sfree(indices); |
| 926 | sfree(connected); |
| 927 | } |
| 928 | |
| 929 | static char *new_game_desc(game_params *params, random_state *rs, |
| 930 | char **aux, int interactive) |
| 931 | { |
| 932 | int w = params->w, h = params->h, W = w+1, H = h+1; |
| 933 | signed char *soln, *tmpsoln, *clues; |
| 934 | int *clueindices; |
| 935 | struct solver_scratch *sc; |
| 936 | int x, y, v, i, j; |
| 937 | char *desc; |
| 938 | |
| 939 | soln = snewn(w*h, signed char); |
| 940 | tmpsoln = snewn(w*h, signed char); |
| 941 | clues = snewn(W*H, signed char); |
| 942 | clueindices = snewn(W*H, int); |
| 943 | sc = new_scratch(w, h); |
| 944 | |
| 945 | do { |
| 946 | /* |
| 947 | * Create the filled grid. |
| 948 | */ |
| 949 | slant_generate(w, h, soln, rs); |
| 950 | |
| 951 | /* |
| 952 | * Fill in the complete set of clues. |
| 953 | */ |
| 954 | for (y = 0; y < H; y++) |
| 955 | for (x = 0; x < W; x++) { |
| 956 | v = 0; |
| 957 | |
| 958 | if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] == -1) v++; |
| 959 | if (x > 0 && y < h && soln[y*w+(x-1)] == +1) v++; |
| 960 | if (x < w && y > 0 && soln[(y-1)*w+x] == +1) v++; |
| 961 | if (x < w && y < h && soln[y*w+x] == -1) v++; |
| 962 | |
| 963 | clues[y*W+x] = v; |
| 964 | } |
| 965 | |
| 966 | /* |
| 967 | * With all clue points filled in, all puzzles are easy: we can |
| 968 | * simply process the clue points in lexicographic order, and |
| 969 | * at each clue point we will always have at most one square |
| 970 | * undecided, which we can then fill in uniquely. |
| 971 | */ |
| 972 | assert(slant_solve(w, h, clues, tmpsoln, sc, DIFF_EASY) == 1); |
| 973 | |
| 974 | /* |
| 975 | * Remove as many clues as possible while retaining solubility. |
| 976 | * |
| 977 | * In DIFF_HARD mode, we prioritise the removal of obvious |
| 978 | * starting points (4s, 0s, border 2s and corner 1s), on |
| 979 | * the grounds that having as few of these as possible |
| 980 | * seems like a good thing. In particular, we can often get |
| 981 | * away without _any_ completely obvious starting points, |
| 982 | * which is even better. |
| 983 | */ |
| 984 | for (i = 0; i < W*H; i++) |
| 985 | clueindices[i] = i; |
| 986 | shuffle(clueindices, W*H, sizeof(*clueindices), rs); |
| 987 | for (j = 0; j < 2; j++) { |
| 988 | for (i = 0; i < W*H; i++) { |
| 989 | int pass, yb, xb; |
| 990 | |
| 991 | y = clueindices[i] / W; |
| 992 | x = clueindices[i] % W; |
| 993 | v = clues[y*W+x]; |
| 994 | |
| 995 | /* |
| 996 | * Identify which pass we should process this point |
| 997 | * in. If it's an obvious start point, _or_ we're |
| 998 | * in DIFF_EASY, then it goes in pass 0; otherwise |
| 999 | * pass 1. |
| 1000 | */ |
| 1001 | xb = (x == 0 || x == W-1); |
| 1002 | yb = (y == 0 || y == H-1); |
| 1003 | if (params->diff == DIFF_EASY || v == 4 || v == 0 || |
| 1004 | (v == 2 && (xb||yb)) || (v == 1 && xb && yb)) |
| 1005 | pass = 0; |
| 1006 | else |
| 1007 | pass = 1; |
| 1008 | |
| 1009 | if (pass == j) { |
| 1010 | clues[y*W+x] = -1; |
| 1011 | if (slant_solve(w, h, clues, tmpsoln, sc, |
| 1012 | params->diff) != 1) |
| 1013 | clues[y*W+x] = v; /* put it back */ |
| 1014 | } |
| 1015 | } |
| 1016 | } |
| 1017 | |
| 1018 | /* |
| 1019 | * And finally, verify that the grid is of _at least_ the |
| 1020 | * requested difficulty, by running the solver one level |
| 1021 | * down and verifying that it can't manage it. |
| 1022 | */ |
| 1023 | } while (params->diff > 0 && |
| 1024 | slant_solve(w, h, clues, tmpsoln, sc, params->diff - 1) <= 1); |
| 1025 | |
| 1026 | /* |
| 1027 | * Now we have the clue set as it will be presented to the |
| 1028 | * user. Encode it in a game desc. |
| 1029 | */ |
| 1030 | { |
| 1031 | char *p; |
| 1032 | int run, i; |
| 1033 | |
| 1034 | desc = snewn(W*H+1, char); |
| 1035 | p = desc; |
| 1036 | run = 0; |
| 1037 | for (i = 0; i <= W*H; i++) { |
| 1038 | int n = (i < W*H ? clues[i] : -2); |
| 1039 | |
| 1040 | if (n == -1) |
| 1041 | run++; |
| 1042 | else { |
| 1043 | if (run) { |
| 1044 | while (run > 0) { |
| 1045 | int c = 'a' - 1 + run; |
| 1046 | if (run > 26) |
| 1047 | c = 'z'; |
| 1048 | *p++ = c; |
| 1049 | run -= c - ('a' - 1); |
| 1050 | } |
| 1051 | } |
| 1052 | if (n >= 0) |
| 1053 | *p++ = '0' + n; |
| 1054 | run = 0; |
| 1055 | } |
| 1056 | } |
| 1057 | assert(p - desc <= W*H); |
| 1058 | *p++ = '\0'; |
| 1059 | desc = sresize(desc, p - desc, char); |
| 1060 | } |
| 1061 | |
| 1062 | /* |
| 1063 | * Encode the solution as an aux_info. |
| 1064 | */ |
| 1065 | { |
| 1066 | char *auxbuf; |
| 1067 | *aux = auxbuf = snewn(w*h+1, char); |
| 1068 | for (i = 0; i < w*h; i++) |
| 1069 | auxbuf[i] = soln[i] < 0 ? '\\' : '/'; |
| 1070 | auxbuf[w*h] = '\0'; |
| 1071 | } |
| 1072 | |
| 1073 | free_scratch(sc); |
| 1074 | sfree(clueindices); |
| 1075 | sfree(clues); |
| 1076 | sfree(tmpsoln); |
| 1077 | sfree(soln); |
| 1078 | |
| 1079 | return desc; |
| 1080 | } |
| 1081 | |
| 1082 | static char *validate_desc(game_params *params, char *desc) |
| 1083 | { |
| 1084 | int w = params->w, h = params->h, W = w+1, H = h+1; |
| 1085 | int area = W*H; |
| 1086 | int squares = 0; |
| 1087 | |
| 1088 | while (*desc) { |
| 1089 | int n = *desc++; |
| 1090 | if (n >= 'a' && n <= 'z') { |
| 1091 | squares += n - 'a' + 1; |
| 1092 | } else if (n >= '0' && n <= '4') { |
| 1093 | squares++; |
| 1094 | } else |
| 1095 | return "Invalid character in game description"; |
| 1096 | } |
| 1097 | |
| 1098 | if (squares < area) |
| 1099 | return "Not enough data to fill grid"; |
| 1100 | |
| 1101 | if (squares > area) |
| 1102 | return "Too much data to fit in grid"; |
| 1103 | |
| 1104 | return NULL; |
| 1105 | } |
| 1106 | |
| 1107 | static game_state *new_game(midend *me, game_params *params, char *desc) |
| 1108 | { |
| 1109 | int w = params->w, h = params->h, W = w+1, H = h+1; |
| 1110 | game_state *state = snew(game_state); |
| 1111 | int area = W*H; |
| 1112 | int squares = 0; |
| 1113 | |
| 1114 | state->p = *params; |
| 1115 | state->soln = snewn(w*h, signed char); |
| 1116 | memset(state->soln, 0, w*h); |
| 1117 | state->completed = state->used_solve = FALSE; |
| 1118 | state->errors = snewn(W*H, unsigned char); |
| 1119 | memset(state->errors, 0, W*H); |
| 1120 | |
| 1121 | state->clues = snew(game_clues); |
| 1122 | state->clues->w = w; |
| 1123 | state->clues->h = h; |
| 1124 | state->clues->clues = snewn(W*H, signed char); |
| 1125 | state->clues->refcount = 1; |
| 1126 | state->clues->tmpdsf = snewn(W*H, int); |
| 1127 | memset(state->clues->clues, -1, W*H); |
| 1128 | while (*desc) { |
| 1129 | int n = *desc++; |
| 1130 | if (n >= 'a' && n <= 'z') { |
| 1131 | squares += n - 'a' + 1; |
| 1132 | } else if (n >= '0' && n <= '4') { |
| 1133 | state->clues->clues[squares++] = n - '0'; |
| 1134 | } else |
| 1135 | assert(!"can't get here"); |
| 1136 | } |
| 1137 | assert(squares == area); |
| 1138 | |
| 1139 | return state; |
| 1140 | } |
| 1141 | |
| 1142 | static game_state *dup_game(game_state *state) |
| 1143 | { |
| 1144 | int w = state->p.w, h = state->p.h, W = w+1, H = h+1; |
| 1145 | game_state *ret = snew(game_state); |
| 1146 | |
| 1147 | ret->p = state->p; |
| 1148 | ret->clues = state->clues; |
| 1149 | ret->clues->refcount++; |
| 1150 | ret->completed = state->completed; |
| 1151 | ret->used_solve = state->used_solve; |
| 1152 | |
| 1153 | ret->soln = snewn(w*h, signed char); |
| 1154 | memcpy(ret->soln, state->soln, w*h); |
| 1155 | |
| 1156 | ret->errors = snewn(W*H, unsigned char); |
| 1157 | memcpy(ret->errors, state->errors, W*H); |
| 1158 | |
| 1159 | return ret; |
| 1160 | } |
| 1161 | |
| 1162 | static void free_game(game_state *state) |
| 1163 | { |
| 1164 | sfree(state->errors); |
| 1165 | sfree(state->soln); |
| 1166 | assert(state->clues); |
| 1167 | if (--state->clues->refcount <= 0) { |
| 1168 | sfree(state->clues->clues); |
| 1169 | sfree(state->clues->tmpdsf); |
| 1170 | sfree(state->clues); |
| 1171 | } |
| 1172 | sfree(state); |
| 1173 | } |
| 1174 | |
| 1175 | /* |
| 1176 | * Utility function to return the current degree of a vertex. If |
| 1177 | * `anti' is set, it returns the number of filled-in edges |
| 1178 | * surrounding the point which _don't_ connect to it; thus 4 minus |
| 1179 | * its anti-degree is the maximum degree it could have if all the |
| 1180 | * empty spaces around it were filled in. |
| 1181 | * |
| 1182 | * (Yes, _4_ minus its anti-degree even if it's a border vertex.) |
| 1183 | * |
| 1184 | * If ret > 0, *sx and *sy are set to the coordinates of one of the |
| 1185 | * squares that contributed to it. |
| 1186 | */ |
| 1187 | static int vertex_degree(int w, int h, signed char *soln, int x, int y, |
| 1188 | int anti, int *sx, int *sy) |
| 1189 | { |
| 1190 | int ret = 0; |
| 1191 | |
| 1192 | assert(x >= 0 && x <= w && y >= 0 && y <= h); |
| 1193 | if (x > 0 && y > 0 && soln[(y-1)*w+(x-1)] - anti < 0) { |
| 1194 | if (sx) *sx = x-1; |
| 1195 | if (sy) *sy = y-1; |
| 1196 | ret++; |
| 1197 | } |
| 1198 | if (x > 0 && y < h && soln[y*w+(x-1)] + anti > 0) { |
| 1199 | if (sx) *sx = x-1; |
| 1200 | if (sy) *sy = y; |
| 1201 | ret++; |
| 1202 | } |
| 1203 | if (x < w && y > 0 && soln[(y-1)*w+x] + anti > 0) { |
| 1204 | if (sx) *sx = x; |
| 1205 | if (sy) *sy = y-1; |
| 1206 | ret++; |
| 1207 | } |
| 1208 | if (x < w && y < h && soln[y*w+x] - anti < 0) { |
| 1209 | if (sx) *sx = x; |
| 1210 | if (sy) *sy = y; |
| 1211 | ret++; |
| 1212 | } |
| 1213 | |
| 1214 | return anti ? 4 - ret : ret; |
| 1215 | } |
| 1216 | |
| 1217 | static int check_completion(game_state *state) |
| 1218 | { |
| 1219 | int w = state->p.w, h = state->p.h, W = w+1, H = h+1; |
| 1220 | int i, x, y, err = FALSE; |
| 1221 | int *dsf; |
| 1222 | |
| 1223 | memset(state->errors, 0, W*H); |
| 1224 | |
| 1225 | /* |
| 1226 | * To detect loops in the grid, we iterate through each edge |
| 1227 | * building up a dsf of connected components, and raise the |
| 1228 | * alarm whenever we find an edge that connects two |
| 1229 | * already-connected vertices. |
| 1230 | * |
| 1231 | * We use the `tmpdsf' scratch space in the shared clues |
| 1232 | * structure, to avoid mallocing too often. |
| 1233 | * |
| 1234 | * When we find such an edge, we then search around the grid to |
| 1235 | * find the loop it is a part of, so that we can highlight it |
| 1236 | * as an error for the user. We do this by the hand-on-one-wall |
| 1237 | * technique: the search will follow branches off the inside of |
| 1238 | * the loop, discover they're dead ends, and unhighlight them |
| 1239 | * again when returning to the actual loop. |
| 1240 | * |
| 1241 | * This technique guarantees that every loop it tracks will |
| 1242 | * surround a disjoint area of the grid (since if an existing |
| 1243 | * loop appears on the boundary of a new one, so that there are |
| 1244 | * multiple possible paths that would come back to the starting |
| 1245 | * point, it will pick the one that allows it to turn right |
| 1246 | * most sharply and hence the one that does not re-surround the |
| 1247 | * area of the previous one). Thus, the total time taken in |
| 1248 | * searching round loops is linear in the grid area since every |
| 1249 | * edge is visited at most twice. |
| 1250 | */ |
| 1251 | dsf = state->clues->tmpdsf; |
| 1252 | for (i = 0; i < W*H; i++) |
| 1253 | dsf[i] = i; /* initially all distinct */ |
| 1254 | for (y = 0; y < h; y++) |
| 1255 | for (x = 0; x < w; x++) { |
| 1256 | int i1, i2; |
| 1257 | |
| 1258 | if (state->soln[y*w+x] == 0) |
| 1259 | continue; |
| 1260 | if (state->soln[y*w+x] < 0) { |
| 1261 | i1 = y*W+x; |
| 1262 | i2 = (y+1)*W+(x+1); |
| 1263 | } else { |
| 1264 | i1 = y*W+(x+1); |
| 1265 | i2 = (y+1)*W+x; |
| 1266 | } |
| 1267 | |
| 1268 | /* |
| 1269 | * Our edge connects i1 with i2. If they're already |
| 1270 | * connected, flag an error. Otherwise, link them. |
| 1271 | */ |
| 1272 | if (dsf_canonify(dsf, i1) == dsf_canonify(dsf, i2)) { |
| 1273 | int x1, y1, x2, y2, dx, dy, dt, pass; |
| 1274 | |
| 1275 | err = TRUE; |
| 1276 | |
| 1277 | /* |
| 1278 | * Now search around the boundary of the loop to |
| 1279 | * highlight it. |
| 1280 | * |
| 1281 | * We have to do this in two passes. The first |
| 1282 | * time, we toggle ERR_SQUARE_TMP on each edge; |
| 1283 | * this pass terminates with ERR_SQUARE_TMP set on |
| 1284 | * exactly the loop edges. In the second pass, we |
| 1285 | * trace round that loop again and turn |
| 1286 | * ERR_SQUARE_TMP into ERR_SQUARE. We have to do |
| 1287 | * this because otherwise we might cancel part of a |
| 1288 | * loop highlighted in a previous iteration of the |
| 1289 | * outer loop. |
| 1290 | */ |
| 1291 | |
| 1292 | for (pass = 0; pass < 2; pass++) { |
| 1293 | |
| 1294 | x1 = i1 % W; |
| 1295 | y1 = i1 / W; |
| 1296 | x2 = i2 % W; |
| 1297 | y2 = i2 / W; |
| 1298 | |
| 1299 | do { |
| 1300 | /* Mark this edge. */ |
| 1301 | if (pass == 0) { |
| 1302 | state->errors[min(y1,y2)*W+min(x1,x2)] ^= |
| 1303 | ERR_SQUARE_TMP; |
| 1304 | } else { |
| 1305 | state->errors[min(y1,y2)*W+min(x1,x2)] |= |
| 1306 | ERR_SQUARE; |
| 1307 | state->errors[min(y1,y2)*W+min(x1,x2)] &= |
| 1308 | ~ERR_SQUARE_TMP; |
| 1309 | } |
| 1310 | |
| 1311 | /* |
| 1312 | * Progress to the next edge by turning as |
| 1313 | * sharply right as possible. In fact we do |
| 1314 | * this by facing back along the edge and |
| 1315 | * turning _left_ until we see an edge we |
| 1316 | * can follow. |
| 1317 | */ |
| 1318 | dx = x1 - x2; |
| 1319 | dy = y1 - y2; |
| 1320 | |
| 1321 | for (i = 0; i < 4; i++) { |
| 1322 | /* |
| 1323 | * Rotate (dx,dy) to the left. |
| 1324 | */ |
| 1325 | dt = dx; dx = dy; dy = -dt; |
| 1326 | |
| 1327 | /* |
| 1328 | * See if (x2,y2) has an edge in direction |
| 1329 | * (dx,dy). |
| 1330 | */ |
| 1331 | if (x2+dx < 0 || x2+dx >= W || |
| 1332 | y2+dy < 0 || y2+dy >= H) |
| 1333 | continue; /* off the side of the grid */ |
| 1334 | /* In the second pass, ignore unmarked edges. */ |
| 1335 | if (pass == 1 && |
| 1336 | !(state->errors[(y2-(dy<0))*W+x2-(dx<0)] & |
| 1337 | ERR_SQUARE_TMP)) |
| 1338 | continue; |
| 1339 | if (state->soln[(y2-(dy<0))*w+x2-(dx<0)] == |
| 1340 | (dx==dy ? -1 : +1)) |
| 1341 | break; |
| 1342 | } |
| 1343 | |
| 1344 | /* |
| 1345 | * In pass 0, we expect to have found |
| 1346 | * _some_ edge we can follow, even if it |
| 1347 | * was found by rotating all the way round |
| 1348 | * and going back the way we came. |
| 1349 | * |
| 1350 | * In pass 1, because we're removing the |
| 1351 | * mark on each edge that allows us to |
| 1352 | * follow it, we expect to find _no_ edge |
| 1353 | * we can follow when we've come all the |
| 1354 | * way round the loop. |
| 1355 | */ |
| 1356 | if (pass == 1 && i == 4) |
| 1357 | break; |
| 1358 | assert(i < 4); |
| 1359 | |
| 1360 | /* |
| 1361 | * Set x1,y1 to x2,y2, and x2,y2 to be the |
| 1362 | * other end of the new edge. |
| 1363 | */ |
| 1364 | x1 = x2; |
| 1365 | y1 = y2; |
| 1366 | x2 += dx; |
| 1367 | y2 += dy; |
| 1368 | } while (y2*W+x2 != i2); |
| 1369 | |
| 1370 | } |
| 1371 | |
| 1372 | } else |
| 1373 | dsf_merge(dsf, i1, i2); |
| 1374 | } |
| 1375 | |
| 1376 | /* |
| 1377 | * Now go through and check the degree of each clue vertex, and |
| 1378 | * mark it with ERR_VERTEX if it cannot be fulfilled. |
| 1379 | */ |
| 1380 | for (y = 0; y < H; y++) |
| 1381 | for (x = 0; x < W; x++) { |
| 1382 | int c; |
| 1383 | |
| 1384 | if ((c = state->clues->clues[y*W+x]) < 0) |
| 1385 | continue; |
| 1386 | |
| 1387 | /* |
| 1388 | * Check to see if there are too many connections to |
| 1389 | * this vertex _or_ too many non-connections. Either is |
| 1390 | * grounds for marking the vertex as erroneous. |
| 1391 | */ |
| 1392 | if (vertex_degree(w, h, state->soln, x, y, |
| 1393 | FALSE, NULL, NULL) > c || |
| 1394 | vertex_degree(w, h, state->soln, x, y, |
| 1395 | TRUE, NULL, NULL) > 4-c) { |
| 1396 | state->errors[y*W+x] |= ERR_VERTEX; |
| 1397 | err = TRUE; |
| 1398 | } |
| 1399 | } |
| 1400 | |
| 1401 | /* |
| 1402 | * Now our actual victory condition is that (a) none of the |
| 1403 | * above code marked anything as erroneous, and (b) every |
| 1404 | * square has an edge in it. |
| 1405 | */ |
| 1406 | |
| 1407 | if (err) |
| 1408 | return FALSE; |
| 1409 | |
| 1410 | for (y = 0; y < h; y++) |
| 1411 | for (x = 0; x < w; x++) |
| 1412 | if (state->soln[y*w+x] == 0) |
| 1413 | return FALSE; |
| 1414 | |
| 1415 | return TRUE; |
| 1416 | } |
| 1417 | |
| 1418 | static char *solve_game(game_state *state, game_state *currstate, |
| 1419 | char *aux, char **error) |
| 1420 | { |
| 1421 | int w = state->p.w, h = state->p.h; |
| 1422 | signed char *soln; |
| 1423 | int bs, ret; |
| 1424 | int free_soln = FALSE; |
| 1425 | char *move, buf[80]; |
| 1426 | int movelen, movesize; |
| 1427 | int x, y; |
| 1428 | |
| 1429 | if (aux) { |
| 1430 | /* |
| 1431 | * If we already have the solution, save ourselves some |
| 1432 | * time. |
| 1433 | */ |
| 1434 | soln = (signed char *)aux; |
| 1435 | bs = (signed char)'\\'; |
| 1436 | free_soln = FALSE; |
| 1437 | } else { |
| 1438 | struct solver_scratch *sc = new_scratch(w, h); |
| 1439 | soln = snewn(w*h, signed char); |
| 1440 | bs = -1; |
| 1441 | ret = slant_solve(w, h, state->clues->clues, soln, sc, DIFF_HARD); |
| 1442 | free_scratch(sc); |
| 1443 | if (ret != 1) { |
| 1444 | sfree(soln); |
| 1445 | if (ret == 0) |
| 1446 | *error = "This puzzle is not self-consistent"; |
| 1447 | else |
| 1448 | *error = "Unable to find a unique solution for this puzzle"; |
| 1449 | return NULL; |
| 1450 | } |
| 1451 | free_soln = TRUE; |
| 1452 | } |
| 1453 | |
| 1454 | /* |
| 1455 | * Construct a move string which turns the current state into |
| 1456 | * the solved state. |
| 1457 | */ |
| 1458 | movesize = 256; |
| 1459 | move = snewn(movesize, char); |
| 1460 | movelen = 0; |
| 1461 | move[movelen++] = 'S'; |
| 1462 | move[movelen] = '\0'; |
| 1463 | for (y = 0; y < h; y++) |
| 1464 | for (x = 0; x < w; x++) { |
| 1465 | int v = (soln[y*w+x] == bs ? -1 : +1); |
| 1466 | if (state->soln[y*w+x] != v) { |
| 1467 | int len = sprintf(buf, ";%c%d,%d", (int)(v < 0 ? '\\' : '/'), x, y); |
| 1468 | if (movelen + len >= movesize) { |
| 1469 | movesize = movelen + len + 256; |
| 1470 | move = sresize(move, movesize, char); |
| 1471 | } |
| 1472 | strcpy(move + movelen, buf); |
| 1473 | movelen += len; |
| 1474 | } |
| 1475 | } |
| 1476 | |
| 1477 | if (free_soln) |
| 1478 | sfree(soln); |
| 1479 | |
| 1480 | return move; |
| 1481 | } |
| 1482 | |
| 1483 | static char *game_text_format(game_state *state) |
| 1484 | { |
| 1485 | int w = state->p.w, h = state->p.h, W = w+1, H = h+1; |
| 1486 | int x, y, len; |
| 1487 | char *ret, *p; |
| 1488 | |
| 1489 | /* |
| 1490 | * There are h+H rows of w+W columns. |
| 1491 | */ |
| 1492 | len = (h+H) * (w+W+1) + 1; |
| 1493 | ret = snewn(len, char); |
| 1494 | p = ret; |
| 1495 | |
| 1496 | for (y = 0; y < H; y++) { |
| 1497 | for (x = 0; x < W; x++) { |
| 1498 | if (state->clues->clues[y*W+x] >= 0) |
| 1499 | *p++ = state->clues->clues[y*W+x] + '0'; |
| 1500 | else |
| 1501 | *p++ = '+'; |
| 1502 | if (x < w) |
| 1503 | *p++ = '-'; |
| 1504 | } |
| 1505 | *p++ = '\n'; |
| 1506 | if (y < h) { |
| 1507 | for (x = 0; x < W; x++) { |
| 1508 | *p++ = '|'; |
| 1509 | if (x < w) { |
| 1510 | if (state->soln[y*w+x] != 0) |
| 1511 | *p++ = (state->soln[y*w+x] < 0 ? '\\' : '/'); |
| 1512 | else |
| 1513 | *p++ = ' '; |
| 1514 | } |
| 1515 | } |
| 1516 | *p++ = '\n'; |
| 1517 | } |
| 1518 | } |
| 1519 | *p++ = '\0'; |
| 1520 | |
| 1521 | assert(p - ret == len); |
| 1522 | return ret; |
| 1523 | } |
| 1524 | |
| 1525 | static game_ui *new_ui(game_state *state) |
| 1526 | { |
| 1527 | return NULL; |
| 1528 | } |
| 1529 | |
| 1530 | static void free_ui(game_ui *ui) |
| 1531 | { |
| 1532 | } |
| 1533 | |
| 1534 | static char *encode_ui(game_ui *ui) |
| 1535 | { |
| 1536 | return NULL; |
| 1537 | } |
| 1538 | |
| 1539 | static void decode_ui(game_ui *ui, char *encoding) |
| 1540 | { |
| 1541 | } |
| 1542 | |
| 1543 | static void game_changed_state(game_ui *ui, game_state *oldstate, |
| 1544 | game_state *newstate) |
| 1545 | { |
| 1546 | } |
| 1547 | |
| 1548 | #define PREFERRED_TILESIZE 32 |
| 1549 | #define TILESIZE (ds->tilesize) |
| 1550 | #define BORDER TILESIZE |
| 1551 | #define CLUE_RADIUS (TILESIZE / 3) |
| 1552 | #define CLUE_TEXTSIZE (TILESIZE / 2) |
| 1553 | #define COORD(x) ( (x) * TILESIZE + BORDER ) |
| 1554 | #define FROMCOORD(x) ( ((x) - BORDER + TILESIZE) / TILESIZE - 1 ) |
| 1555 | |
| 1556 | #define FLASH_TIME 0.30F |
| 1557 | |
| 1558 | /* |
| 1559 | * Bit fields in the `grid' and `todraw' elements of the drawstate. |
| 1560 | */ |
| 1561 | #define BACKSLASH 0x00000001L |
| 1562 | #define FORWSLASH 0x00000002L |
| 1563 | #define L_T 0x00000004L |
| 1564 | #define ERR_L_T 0x00000008L |
| 1565 | #define L_B 0x00000010L |
| 1566 | #define ERR_L_B 0x00000020L |
| 1567 | #define T_L 0x00000040L |
| 1568 | #define ERR_T_L 0x00000080L |
| 1569 | #define T_R 0x00000100L |
| 1570 | #define ERR_T_R 0x00000200L |
| 1571 | #define C_TL 0x00000400L |
| 1572 | #define ERR_C_TL 0x00000800L |
| 1573 | #define FLASH 0x00001000L |
| 1574 | #define ERRSLASH 0x00002000L |
| 1575 | #define ERR_TL 0x00004000L |
| 1576 | #define ERR_TR 0x00008000L |
| 1577 | #define ERR_BL 0x00010000L |
| 1578 | #define ERR_BR 0x00020000L |
| 1579 | |
| 1580 | struct game_drawstate { |
| 1581 | int tilesize; |
| 1582 | int started; |
| 1583 | long *grid; |
| 1584 | long *todraw; |
| 1585 | }; |
| 1586 | |
| 1587 | static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds, |
| 1588 | int x, int y, int button) |
| 1589 | { |
| 1590 | int w = state->p.w, h = state->p.h; |
| 1591 | |
| 1592 | if (button == LEFT_BUTTON || button == RIGHT_BUTTON) { |
| 1593 | int v; |
| 1594 | char buf[80]; |
| 1595 | |
| 1596 | /* |
| 1597 | * This is an utterly awful hack which I should really sort out |
| 1598 | * by means of a proper configuration mechanism. One Slant |
| 1599 | * player has observed that they prefer the mouse buttons to |
| 1600 | * function exactly the opposite way round, so here's a |
| 1601 | * mechanism for environment-based configuration. I cache the |
| 1602 | * result in a global variable - yuck! - to avoid repeated |
| 1603 | * lookups. |
| 1604 | */ |
| 1605 | { |
| 1606 | static int swap_buttons = -1; |
| 1607 | if (swap_buttons < 0) { |
| 1608 | char *env = getenv("SLANT_SWAP_BUTTONS"); |
| 1609 | swap_buttons = (env && (env[0] == 'y' || env[0] == 'Y')); |
| 1610 | } |
| 1611 | if (swap_buttons) { |
| 1612 | if (button == LEFT_BUTTON) |
| 1613 | button = RIGHT_BUTTON; |
| 1614 | else |
| 1615 | button = LEFT_BUTTON; |
| 1616 | } |
| 1617 | } |
| 1618 | |
| 1619 | x = FROMCOORD(x); |
| 1620 | y = FROMCOORD(y); |
| 1621 | if (x < 0 || y < 0 || x >= w || y >= h) |
| 1622 | return NULL; |
| 1623 | |
| 1624 | if (button == LEFT_BUTTON) { |
| 1625 | /* |
| 1626 | * Left-clicking cycles blank -> \ -> / -> blank. |
| 1627 | */ |
| 1628 | v = state->soln[y*w+x] - 1; |
| 1629 | if (v == -2) |
| 1630 | v = +1; |
| 1631 | } else { |
| 1632 | /* |
| 1633 | * Right-clicking cycles blank -> / -> \ -> blank. |
| 1634 | */ |
| 1635 | v = state->soln[y*w+x] + 1; |
| 1636 | if (v == +2) |
| 1637 | v = -1; |
| 1638 | } |
| 1639 | |
| 1640 | sprintf(buf, "%c%d,%d", (int)(v==-1 ? '\\' : v==+1 ? '/' : 'C'), x, y); |
| 1641 | return dupstr(buf); |
| 1642 | } |
| 1643 | |
| 1644 | return NULL; |
| 1645 | } |
| 1646 | |
| 1647 | static game_state *execute_move(game_state *state, char *move) |
| 1648 | { |
| 1649 | int w = state->p.w, h = state->p.h; |
| 1650 | char c; |
| 1651 | int x, y, n; |
| 1652 | game_state *ret = dup_game(state); |
| 1653 | |
| 1654 | while (*move) { |
| 1655 | c = *move; |
| 1656 | if (c == 'S') { |
| 1657 | ret->used_solve = TRUE; |
| 1658 | move++; |
| 1659 | } else if (c == '\\' || c == '/' || c == 'C') { |
| 1660 | move++; |
| 1661 | if (sscanf(move, "%d,%d%n", &x, &y, &n) != 2 || |
| 1662 | x < 0 || y < 0 || x >= w || y >= h) { |
| 1663 | free_game(ret); |
| 1664 | return NULL; |
| 1665 | } |
| 1666 | ret->soln[y*w+x] = (c == '\\' ? -1 : c == '/' ? +1 : 0); |
| 1667 | move += n; |
| 1668 | } else { |
| 1669 | free_game(ret); |
| 1670 | return NULL; |
| 1671 | } |
| 1672 | if (*move == ';') |
| 1673 | move++; |
| 1674 | else if (*move) { |
| 1675 | free_game(ret); |
| 1676 | return NULL; |
| 1677 | } |
| 1678 | } |
| 1679 | |
| 1680 | /* |
| 1681 | * We never clear the `completed' flag, but we must always |
| 1682 | * re-run the completion check because it also highlights |
| 1683 | * errors in the grid. |
| 1684 | */ |
| 1685 | ret->completed = check_completion(ret) || ret->completed; |
| 1686 | |
| 1687 | return ret; |
| 1688 | } |
| 1689 | |
| 1690 | /* ---------------------------------------------------------------------- |
| 1691 | * Drawing routines. |
| 1692 | */ |
| 1693 | |
| 1694 | static void game_compute_size(game_params *params, int tilesize, |
| 1695 | int *x, int *y) |
| 1696 | { |
| 1697 | /* fool the macros */ |
| 1698 | struct dummy { int tilesize; } dummy = { tilesize }, *ds = &dummy; |
| 1699 | |
| 1700 | *x = 2 * BORDER + params->w * TILESIZE + 1; |
| 1701 | *y = 2 * BORDER + params->h * TILESIZE + 1; |
| 1702 | } |
| 1703 | |
| 1704 | static void game_set_size(drawing *dr, game_drawstate *ds, |
| 1705 | game_params *params, int tilesize) |
| 1706 | { |
| 1707 | ds->tilesize = tilesize; |
| 1708 | } |
| 1709 | |
| 1710 | static float *game_colours(frontend *fe, int *ncolours) |
| 1711 | { |
| 1712 | float *ret = snewn(3 * NCOLOURS, float); |
| 1713 | |
| 1714 | frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]); |
| 1715 | |
| 1716 | ret[COL_GRID * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.7F; |
| 1717 | ret[COL_GRID * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.7F; |
| 1718 | ret[COL_GRID * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] * 0.7F; |
| 1719 | |
| 1720 | ret[COL_INK * 3 + 0] = 0.0F; |
| 1721 | ret[COL_INK * 3 + 1] = 0.0F; |
| 1722 | ret[COL_INK * 3 + 2] = 0.0F; |
| 1723 | |
| 1724 | ret[COL_SLANT1 * 3 + 0] = 0.0F; |
| 1725 | ret[COL_SLANT1 * 3 + 1] = 0.0F; |
| 1726 | ret[COL_SLANT1 * 3 + 2] = 0.0F; |
| 1727 | |
| 1728 | ret[COL_SLANT2 * 3 + 0] = 0.0F; |
| 1729 | ret[COL_SLANT2 * 3 + 1] = 0.0F; |
| 1730 | ret[COL_SLANT2 * 3 + 2] = 0.0F; |
| 1731 | |
| 1732 | ret[COL_ERROR * 3 + 0] = 1.0F; |
| 1733 | ret[COL_ERROR * 3 + 1] = 0.0F; |
| 1734 | ret[COL_ERROR * 3 + 2] = 0.0F; |
| 1735 | |
| 1736 | *ncolours = NCOLOURS; |
| 1737 | return ret; |
| 1738 | } |
| 1739 | |
| 1740 | static game_drawstate *game_new_drawstate(drawing *dr, game_state *state) |
| 1741 | { |
| 1742 | int w = state->p.w, h = state->p.h; |
| 1743 | int i; |
| 1744 | struct game_drawstate *ds = snew(struct game_drawstate); |
| 1745 | |
| 1746 | ds->tilesize = 0; |
| 1747 | ds->started = FALSE; |
| 1748 | ds->grid = snewn((w+2)*(h+2), long); |
| 1749 | ds->todraw = snewn((w+2)*(h+2), long); |
| 1750 | for (i = 0; i < (w+2)*(h+2); i++) |
| 1751 | ds->grid[i] = ds->todraw[i] = -1; |
| 1752 | |
| 1753 | return ds; |
| 1754 | } |
| 1755 | |
| 1756 | static void game_free_drawstate(drawing *dr, game_drawstate *ds) |
| 1757 | { |
| 1758 | sfree(ds->todraw); |
| 1759 | sfree(ds->grid); |
| 1760 | sfree(ds); |
| 1761 | } |
| 1762 | |
| 1763 | static void draw_clue(drawing *dr, game_drawstate *ds, |
| 1764 | int x, int y, long v, long err, int bg, int colour) |
| 1765 | { |
| 1766 | char p[2]; |
| 1767 | int ccol = colour >= 0 ? colour : ((x ^ y) & 1) ? COL_SLANT1 : COL_SLANT2; |
| 1768 | int tcol = colour >= 0 ? colour : err ? COL_ERROR : COL_INK; |
| 1769 | |
| 1770 | if (v < 0) |
| 1771 | return; |
| 1772 | |
| 1773 | p[0] = v + '0'; |
| 1774 | p[1] = '\0'; |
| 1775 | draw_circle(dr, COORD(x), COORD(y), CLUE_RADIUS, |
| 1776 | bg >= 0 ? bg : COL_BACKGROUND, ccol); |
| 1777 | draw_text(dr, COORD(x), COORD(y), FONT_VARIABLE, |
| 1778 | CLUE_TEXTSIZE, ALIGN_VCENTRE|ALIGN_HCENTRE, tcol, p); |
| 1779 | } |
| 1780 | |
| 1781 | static void draw_tile(drawing *dr, game_drawstate *ds, game_clues *clues, |
| 1782 | int x, int y, long v) |
| 1783 | { |
| 1784 | int w = clues->w, h = clues->h, W = w+1 /*, H = h+1 */; |
| 1785 | int chesscolour = (x ^ y) & 1; |
| 1786 | int fscol = chesscolour ? COL_SLANT2 : COL_SLANT1; |
| 1787 | int bscol = chesscolour ? COL_SLANT1 : COL_SLANT2; |
| 1788 | |
| 1789 | clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE); |
| 1790 | |
| 1791 | draw_rect(dr, COORD(x), COORD(y), TILESIZE, TILESIZE, |
| 1792 | (v & FLASH) ? COL_GRID : COL_BACKGROUND); |
| 1793 | |
| 1794 | /* |
| 1795 | * Draw the grid lines. |
| 1796 | */ |
| 1797 | if (x >= 0 && x < w && y >= 0) |
| 1798 | draw_rect(dr, COORD(x), COORD(y), TILESIZE+1, 1, COL_GRID); |
| 1799 | if (x >= 0 && x < w && y < h) |
| 1800 | draw_rect(dr, COORD(x), COORD(y+1), TILESIZE+1, 1, COL_GRID); |
| 1801 | if (y >= 0 && y < h && x >= 0) |
| 1802 | draw_rect(dr, COORD(x), COORD(y), 1, TILESIZE+1, COL_GRID); |
| 1803 | if (y >= 0 && y < h && x < w) |
| 1804 | draw_rect(dr, COORD(x+1), COORD(y), 1, TILESIZE+1, COL_GRID); |
| 1805 | if (x == -1 && y == -1) |
| 1806 | draw_rect(dr, COORD(x+1), COORD(y+1), 1, 1, COL_GRID); |
| 1807 | if (x == -1 && y == h) |
| 1808 | draw_rect(dr, COORD(x+1), COORD(y), 1, 1, COL_GRID); |
| 1809 | if (x == w && y == -1) |
| 1810 | draw_rect(dr, COORD(x), COORD(y+1), 1, 1, COL_GRID); |
| 1811 | if (x == w && y == h) |
| 1812 | draw_rect(dr, COORD(x), COORD(y), 1, 1, COL_GRID); |
| 1813 | |
| 1814 | /* |
| 1815 | * Draw the slash. |
| 1816 | */ |
| 1817 | if (v & BACKSLASH) { |
| 1818 | int scol = (v & ERRSLASH) ? COL_ERROR : bscol; |
| 1819 | draw_line(dr, COORD(x), COORD(y), COORD(x+1), COORD(y+1), scol); |
| 1820 | draw_line(dr, COORD(x)+1, COORD(y), COORD(x+1), COORD(y+1)-1, |
| 1821 | scol); |
| 1822 | draw_line(dr, COORD(x), COORD(y)+1, COORD(x+1)-1, COORD(y+1), |
| 1823 | scol); |
| 1824 | } else if (v & FORWSLASH) { |
| 1825 | int scol = (v & ERRSLASH) ? COL_ERROR : fscol; |
| 1826 | draw_line(dr, COORD(x+1), COORD(y), COORD(x), COORD(y+1), scol); |
| 1827 | draw_line(dr, COORD(x+1)-1, COORD(y), COORD(x), COORD(y+1)-1, |
| 1828 | scol); |
| 1829 | draw_line(dr, COORD(x+1), COORD(y)+1, COORD(x)+1, COORD(y+1), |
| 1830 | scol); |
| 1831 | } |
| 1832 | |
| 1833 | /* |
| 1834 | * Draw dots on the grid corners that appear if a slash is in a |
| 1835 | * neighbouring cell. |
| 1836 | */ |
| 1837 | if (v & (L_T | BACKSLASH)) |
| 1838 | draw_rect(dr, COORD(x), COORD(y)+1, 1, 1, |
| 1839 | (v & ERR_L_T ? COL_ERROR : bscol)); |
| 1840 | if (v & (L_B | FORWSLASH)) |
| 1841 | draw_rect(dr, COORD(x), COORD(y+1)-1, 1, 1, |
| 1842 | (v & ERR_L_B ? COL_ERROR : fscol)); |
| 1843 | if (v & (T_L | BACKSLASH)) |
| 1844 | draw_rect(dr, COORD(x)+1, COORD(y), 1, 1, |
| 1845 | (v & ERR_T_L ? COL_ERROR : bscol)); |
| 1846 | if (v & (T_R | FORWSLASH)) |
| 1847 | draw_rect(dr, COORD(x+1)-1, COORD(y), 1, 1, |
| 1848 | (v & ERR_T_R ? COL_ERROR : fscol)); |
| 1849 | if (v & (C_TL | BACKSLASH)) |
| 1850 | draw_rect(dr, COORD(x), COORD(y), 1, 1, |
| 1851 | (v & ERR_C_TL ? COL_ERROR : bscol)); |
| 1852 | |
| 1853 | /* |
| 1854 | * And finally the clues at the corners. |
| 1855 | */ |
| 1856 | if (x >= 0 && y >= 0) |
| 1857 | draw_clue(dr, ds, x, y, clues->clues[y*W+x], v & ERR_TL, -1, -1); |
| 1858 | if (x < w && y >= 0) |
| 1859 | draw_clue(dr, ds, x+1, y, clues->clues[y*W+(x+1)], v & ERR_TR, -1, -1); |
| 1860 | if (x >= 0 && y < h) |
| 1861 | draw_clue(dr, ds, x, y+1, clues->clues[(y+1)*W+x], v & ERR_BL, -1, -1); |
| 1862 | if (x < w && y < h) |
| 1863 | draw_clue(dr, ds, x+1, y+1, clues->clues[(y+1)*W+(x+1)], v & ERR_BR, |
| 1864 | -1, -1); |
| 1865 | |
| 1866 | unclip(dr); |
| 1867 | draw_update(dr, COORD(x), COORD(y), TILESIZE, TILESIZE); |
| 1868 | } |
| 1869 | |
| 1870 | static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate, |
| 1871 | game_state *state, int dir, game_ui *ui, |
| 1872 | float animtime, float flashtime) |
| 1873 | { |
| 1874 | int w = state->p.w, h = state->p.h, W = w+1, H = h+1; |
| 1875 | int x, y; |
| 1876 | int flashing; |
| 1877 | |
| 1878 | if (flashtime > 0) |
| 1879 | flashing = (int)(flashtime * 3 / FLASH_TIME) != 1; |
| 1880 | else |
| 1881 | flashing = FALSE; |
| 1882 | |
| 1883 | if (!ds->started) { |
| 1884 | int ww, wh; |
| 1885 | game_compute_size(&state->p, TILESIZE, &ww, &wh); |
| 1886 | draw_rect(dr, 0, 0, ww, wh, COL_BACKGROUND); |
| 1887 | draw_update(dr, 0, 0, ww, wh); |
| 1888 | ds->started = TRUE; |
| 1889 | } |
| 1890 | |
| 1891 | /* |
| 1892 | * Loop over the grid and work out where all the slashes are. |
| 1893 | * We need to do this because a slash in one square affects the |
| 1894 | * drawing of the next one along. |
| 1895 | */ |
| 1896 | for (y = -1; y <= h; y++) |
| 1897 | for (x = -1; x <= w; x++) { |
| 1898 | if (x >= 0 && x < w && y >= 0 && y < h) |
| 1899 | ds->todraw[(y+1)*(w+2)+(x+1)] = flashing ? FLASH : 0; |
| 1900 | else |
| 1901 | ds->todraw[(y+1)*(w+2)+(x+1)] = 0; |
| 1902 | } |
| 1903 | |
| 1904 | for (y = 0; y < h; y++) { |
| 1905 | for (x = 0; x < w; x++) { |
| 1906 | int err = state->errors[y*W+x] & ERR_SQUARE; |
| 1907 | |
| 1908 | if (state->soln[y*w+x] < 0) { |
| 1909 | ds->todraw[(y+1)*(w+2)+(x+1)] |= BACKSLASH; |
| 1910 | ds->todraw[(y+2)*(w+2)+(x+1)] |= T_R; |
| 1911 | ds->todraw[(y+1)*(w+2)+(x+2)] |= L_B; |
| 1912 | ds->todraw[(y+2)*(w+2)+(x+2)] |= C_TL; |
| 1913 | if (err) { |
| 1914 | ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH | |
| 1915 | ERR_T_L | ERR_L_T | ERR_C_TL; |
| 1916 | ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_R; |
| 1917 | ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_B; |
| 1918 | ds->todraw[(y+2)*(w+2)+(x+2)] |= ERR_C_TL; |
| 1919 | } |
| 1920 | } else if (state->soln[y*w+x] > 0) { |
| 1921 | ds->todraw[(y+1)*(w+2)+(x+1)] |= FORWSLASH; |
| 1922 | ds->todraw[(y+1)*(w+2)+(x+2)] |= L_T | C_TL; |
| 1923 | ds->todraw[(y+2)*(w+2)+(x+1)] |= T_L | C_TL; |
| 1924 | if (err) { |
| 1925 | ds->todraw[(y+1)*(w+2)+(x+1)] |= ERRSLASH | |
| 1926 | ERR_L_B | ERR_T_R; |
| 1927 | ds->todraw[(y+1)*(w+2)+(x+2)] |= ERR_L_T | ERR_C_TL; |
| 1928 | ds->todraw[(y+2)*(w+2)+(x+1)] |= ERR_T_L | ERR_C_TL; |
| 1929 | } |
| 1930 | } |
| 1931 | } |
| 1932 | } |
| 1933 | |
| 1934 | for (y = 0; y < H; y++) |
| 1935 | for (x = 0; x < W; x++) |
| 1936 | if (state->errors[y*W+x] & ERR_VERTEX) { |
| 1937 | ds->todraw[y*(w+2)+x] |= ERR_BR; |
| 1938 | ds->todraw[y*(w+2)+(x+1)] |= ERR_BL; |
| 1939 | ds->todraw[(y+1)*(w+2)+x] |= ERR_TR; |
| 1940 | ds->todraw[(y+1)*(w+2)+(x+1)] |= ERR_TL; |
| 1941 | } |
| 1942 | |
| 1943 | /* |
| 1944 | * Now go through and draw the grid squares. |
| 1945 | */ |
| 1946 | for (y = -1; y <= h; y++) { |
| 1947 | for (x = -1; x <= w; x++) { |
| 1948 | if (ds->todraw[(y+1)*(w+2)+(x+1)] != ds->grid[(y+1)*(w+2)+(x+1)]) { |
| 1949 | draw_tile(dr, ds, state->clues, x, y, |
| 1950 | ds->todraw[(y+1)*(w+2)+(x+1)]); |
| 1951 | ds->grid[(y+1)*(w+2)+(x+1)] = ds->todraw[(y+1)*(w+2)+(x+1)]; |
| 1952 | } |
| 1953 | } |
| 1954 | } |
| 1955 | } |
| 1956 | |
| 1957 | static float game_anim_length(game_state *oldstate, game_state *newstate, |
| 1958 | int dir, game_ui *ui) |
| 1959 | { |
| 1960 | return 0.0F; |
| 1961 | } |
| 1962 | |
| 1963 | static float game_flash_length(game_state *oldstate, game_state *newstate, |
| 1964 | int dir, game_ui *ui) |
| 1965 | { |
| 1966 | if (!oldstate->completed && newstate->completed && |
| 1967 | !oldstate->used_solve && !newstate->used_solve) |
| 1968 | return FLASH_TIME; |
| 1969 | |
| 1970 | return 0.0F; |
| 1971 | } |
| 1972 | |
| 1973 | static int game_timing_state(game_state *state, game_ui *ui) |
| 1974 | { |
| 1975 | return TRUE; |
| 1976 | } |
| 1977 | |
| 1978 | static void game_print_size(game_params *params, float *x, float *y) |
| 1979 | { |
| 1980 | int pw, ph; |
| 1981 | |
| 1982 | /* |
| 1983 | * I'll use 6mm squares by default. |
| 1984 | */ |
| 1985 | game_compute_size(params, 600, &pw, &ph); |
| 1986 | *x = pw / 100.0; |
| 1987 | *y = ph / 100.0; |
| 1988 | } |
| 1989 | |
| 1990 | static void game_print(drawing *dr, game_state *state, int tilesize) |
| 1991 | { |
| 1992 | int w = state->p.w, h = state->p.h, W = w+1; |
| 1993 | int ink = print_mono_colour(dr, 0); |
| 1994 | int paper = print_mono_colour(dr, 1); |
| 1995 | int x, y; |
| 1996 | |
| 1997 | /* Ick: fake up `ds->tilesize' for macro expansion purposes */ |
| 1998 | game_drawstate ads, *ds = &ads; |
| 1999 | game_set_size(dr, ds, NULL, tilesize); |
| 2000 | |
| 2001 | /* |
| 2002 | * Border. |
| 2003 | */ |
| 2004 | print_line_width(dr, TILESIZE / 16); |
| 2005 | draw_rect_outline(dr, COORD(0), COORD(0), w*TILESIZE, h*TILESIZE, ink); |
| 2006 | |
| 2007 | /* |
| 2008 | * Grid. |
| 2009 | */ |
| 2010 | print_line_width(dr, TILESIZE / 24); |
| 2011 | for (x = 1; x < w; x++) |
| 2012 | draw_line(dr, COORD(x), COORD(0), COORD(x), COORD(h), ink); |
| 2013 | for (y = 1; y < h; y++) |
| 2014 | draw_line(dr, COORD(0), COORD(y), COORD(w), COORD(y), ink); |
| 2015 | |
| 2016 | /* |
| 2017 | * Solution. |
| 2018 | */ |
| 2019 | print_line_width(dr, TILESIZE / 12); |
| 2020 | for (y = 0; y < h; y++) |
| 2021 | for (x = 0; x < w; x++) |
| 2022 | if (state->soln[y*w+x]) { |
| 2023 | int ly, ry; |
| 2024 | /* |
| 2025 | * To prevent nasty line-ending artefacts at |
| 2026 | * corners, I'll do something slightly cunning |
| 2027 | * here. |
| 2028 | */ |
| 2029 | clip(dr, COORD(x), COORD(y), TILESIZE, TILESIZE); |
| 2030 | if (state->soln[y*w+x] < 0) |
| 2031 | ly = y-1, ry = y+2; |
| 2032 | else |
| 2033 | ry = y-1, ly = y+2; |
| 2034 | draw_line(dr, COORD(x-1), COORD(ly), COORD(x+2), COORD(ry), |
| 2035 | ink); |
| 2036 | unclip(dr); |
| 2037 | } |
| 2038 | |
| 2039 | /* |
| 2040 | * Clues. |
| 2041 | */ |
| 2042 | print_line_width(dr, TILESIZE / 24); |
| 2043 | for (y = 0; y <= h; y++) |
| 2044 | for (x = 0; x <= w; x++) |
| 2045 | draw_clue(dr, ds, x, y, state->clues->clues[y*W+x], |
| 2046 | FALSE, paper, ink); |
| 2047 | } |
| 2048 | |
| 2049 | #ifdef COMBINED |
| 2050 | #define thegame slant |
| 2051 | #endif |
| 2052 | |
| 2053 | const struct game thegame = { |
| 2054 | "Slant", "games.slant", |
| 2055 | default_params, |
| 2056 | game_fetch_preset, |
| 2057 | decode_params, |
| 2058 | encode_params, |
| 2059 | free_params, |
| 2060 | dup_params, |
| 2061 | TRUE, game_configure, custom_params, |
| 2062 | validate_params, |
| 2063 | new_game_desc, |
| 2064 | validate_desc, |
| 2065 | new_game, |
| 2066 | dup_game, |
| 2067 | free_game, |
| 2068 | TRUE, solve_game, |
| 2069 | TRUE, game_text_format, |
| 2070 | new_ui, |
| 2071 | free_ui, |
| 2072 | encode_ui, |
| 2073 | decode_ui, |
| 2074 | game_changed_state, |
| 2075 | interpret_move, |
| 2076 | execute_move, |
| 2077 | PREFERRED_TILESIZE, game_compute_size, game_set_size, |
| 2078 | game_colours, |
| 2079 | game_new_drawstate, |
| 2080 | game_free_drawstate, |
| 2081 | game_redraw, |
| 2082 | game_anim_length, |
| 2083 | game_flash_length, |
| 2084 | TRUE, FALSE, game_print_size, game_print, |
| 2085 | FALSE, /* wants_statusbar */ |
| 2086 | FALSE, game_timing_state, |
| 2087 | 0, /* flags */ |
| 2088 | }; |
| 2089 | |
| 2090 | #ifdef STANDALONE_SOLVER |
| 2091 | |
| 2092 | #include <stdarg.h> |
| 2093 | |
| 2094 | int main(int argc, char **argv) |
| 2095 | { |
| 2096 | game_params *p; |
| 2097 | game_state *s; |
| 2098 | char *id = NULL, *desc, *err; |
| 2099 | int grade = FALSE; |
| 2100 | int ret, diff, really_verbose = FALSE; |
| 2101 | struct solver_scratch *sc; |
| 2102 | |
| 2103 | while (--argc > 0) { |
| 2104 | char *p = *++argv; |
| 2105 | if (!strcmp(p, "-v")) { |
| 2106 | really_verbose = TRUE; |
| 2107 | } else if (!strcmp(p, "-g")) { |
| 2108 | grade = TRUE; |
| 2109 | } else if (*p == '-') { |
| 2110 | fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p); |
| 2111 | return 1; |
| 2112 | } else { |
| 2113 | id = p; |
| 2114 | } |
| 2115 | } |
| 2116 | |
| 2117 | if (!id) { |
| 2118 | fprintf(stderr, "usage: %s [-g | -v] <game_id>\n", argv[0]); |
| 2119 | return 1; |
| 2120 | } |
| 2121 | |
| 2122 | desc = strchr(id, ':'); |
| 2123 | if (!desc) { |
| 2124 | fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]); |
| 2125 | return 1; |
| 2126 | } |
| 2127 | *desc++ = '\0'; |
| 2128 | |
| 2129 | p = default_params(); |
| 2130 | decode_params(p, id); |
| 2131 | err = validate_desc(p, desc); |
| 2132 | if (err) { |
| 2133 | fprintf(stderr, "%s: %s\n", argv[0], err); |
| 2134 | return 1; |
| 2135 | } |
| 2136 | s = new_game(NULL, p, desc); |
| 2137 | |
| 2138 | sc = new_scratch(p->w, p->h); |
| 2139 | |
| 2140 | /* |
| 2141 | * When solving an Easy puzzle, we don't want to bother the |
| 2142 | * user with Hard-level deductions. For this reason, we grade |
| 2143 | * the puzzle internally before doing anything else. |
| 2144 | */ |
| 2145 | ret = -1; /* placate optimiser */ |
| 2146 | for (diff = 0; diff < DIFFCOUNT; diff++) { |
| 2147 | ret = slant_solve(p->w, p->h, s->clues->clues, |
| 2148 | s->soln, sc, diff); |
| 2149 | if (ret < 2) |
| 2150 | break; |
| 2151 | } |
| 2152 | |
| 2153 | if (diff == DIFFCOUNT) { |
| 2154 | if (grade) |
| 2155 | printf("Difficulty rating: harder than Hard, or ambiguous\n"); |
| 2156 | else |
| 2157 | printf("Unable to find a unique solution\n"); |
| 2158 | } else { |
| 2159 | if (grade) { |
| 2160 | if (ret == 0) |
| 2161 | printf("Difficulty rating: impossible (no solution exists)\n"); |
| 2162 | else if (ret == 1) |
| 2163 | printf("Difficulty rating: %s\n", slant_diffnames[diff]); |
| 2164 | } else { |
| 2165 | verbose = really_verbose; |
| 2166 | ret = slant_solve(p->w, p->h, s->clues->clues, |
| 2167 | s->soln, sc, diff); |
| 2168 | if (ret == 0) |
| 2169 | printf("Puzzle is inconsistent\n"); |
| 2170 | else |
| 2171 | fputs(game_text_format(s), stdout); |
| 2172 | } |
| 2173 | } |
| 2174 | |
| 2175 | return 0; |
| 2176 | } |
| 2177 | |
| 2178 | #endif |