| 1 | /* |
| 2 | * solo.c: the number-placing puzzle most popularly known as `Sudoku'. |
| 3 | * |
| 4 | * TODO: |
| 5 | * |
| 6 | * - can we do anything about nasty centring of text in GTK? It |
| 7 | * seems to be taking ascenders/descenders into account when |
| 8 | * centring. Ick. |
| 9 | * |
| 10 | * - implement stronger modes of reasoning in nsolve, thus |
| 11 | * enabling harder puzzles |
| 12 | * + and having done that, supply configurable difficulty |
| 13 | * levels |
| 14 | * |
| 15 | * - it might still be nice to do some prioritisation on the |
| 16 | * removal of numbers from the grid |
| 17 | * + one possibility is to try to minimise the maximum number |
| 18 | * of filled squares in any block, which in particular ought |
| 19 | * to enforce never leaving a completely filled block in the |
| 20 | * puzzle as presented. |
| 21 | * + be careful of being too clever here, though, until after |
| 22 | * I've tried implementing difficulty levels. It's not |
| 23 | * impossible that those might impose much more important |
| 24 | * constraints on this process. |
| 25 | * |
| 26 | * - alternative interface modes |
| 27 | * + sudoku.com's Windows program has a palette of possible |
| 28 | * entries; you select a palette entry first and then click |
| 29 | * on the square you want it to go in, thus enabling |
| 30 | * mouse-only play. Useful for PDAs! I don't think it's |
| 31 | * actually incompatible with the current highlight-then-type |
| 32 | * approach: you _either_ highlight a palette entry and then |
| 33 | * click, _or_ you highlight a square and then type. At most |
| 34 | * one thing is ever highlighted at a time, so there's no way |
| 35 | * to confuse the two. |
| 36 | * + `pencil marks' might be useful for more subtle forms of |
| 37 | * deduction, once we implement creation of puzzles that |
| 38 | * require it. |
| 39 | */ |
| 40 | |
| 41 | /* |
| 42 | * Solo puzzles need to be square overall (since each row and each |
| 43 | * column must contain one of every digit), but they need not be |
| 44 | * subdivided the same way internally. I am going to adopt a |
| 45 | * convention whereby I _always_ refer to `r' as the number of rows |
| 46 | * of _big_ divisions, and `c' as the number of columns of _big_ |
| 47 | * divisions. Thus, a 2c by 3r puzzle looks something like this: |
| 48 | * |
| 49 | * 4 5 1 | 2 6 3 |
| 50 | * 6 3 2 | 5 4 1 |
| 51 | * ------+------ (Of course, you can't subdivide it the other way |
| 52 | * 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the |
| 53 | * 3 2 6 | 4 1 5 top left would conflict with the 4 in the second |
| 54 | * ------+------ box down on the left-hand side.) |
| 55 | * 5 1 4 | 3 2 6 |
| 56 | * 2 6 3 | 1 5 4 |
| 57 | * |
| 58 | * The need for a strong naming convention should now be clear: |
| 59 | * each small box is two rows of digits by three columns, while the |
| 60 | * overall puzzle has three rows of small boxes by two columns. So |
| 61 | * I will (hopefully) consistently use `r' to denote the number of |
| 62 | * rows _of small boxes_ (here 3), which is also the number of |
| 63 | * columns of digits in each small box; and `c' vice versa (here |
| 64 | * 2). |
| 65 | * |
| 66 | * I'm also going to choose arbitrarily to list c first wherever |
| 67 | * possible: the above is a 2x3 puzzle, not a 3x2 one. |
| 68 | */ |
| 69 | |
| 70 | #include <stdio.h> |
| 71 | #include <stdlib.h> |
| 72 | #include <string.h> |
| 73 | #include <assert.h> |
| 74 | #include <ctype.h> |
| 75 | #include <math.h> |
| 76 | |
| 77 | #include "puzzles.h" |
| 78 | |
| 79 | /* |
| 80 | * To save space, I store digits internally as unsigned char. This |
| 81 | * imposes a hard limit of 255 on the order of the puzzle. Since |
| 82 | * even a 5x5 takes unacceptably long to generate, I don't see this |
| 83 | * as a serious limitation unless something _really_ impressive |
| 84 | * happens in computing technology; but here's a typedef anyway for |
| 85 | * general good practice. |
| 86 | */ |
| 87 | typedef unsigned char digit; |
| 88 | #define ORDER_MAX 255 |
| 89 | |
| 90 | #define TILE_SIZE 32 |
| 91 | #define BORDER 18 |
| 92 | |
| 93 | #define FLASH_TIME 0.4F |
| 94 | |
| 95 | enum { SYMM_NONE, SYMM_ROT2, SYMM_ROT4, SYMM_REF4 }; |
| 96 | |
| 97 | enum { |
| 98 | COL_BACKGROUND, |
| 99 | COL_GRID, |
| 100 | COL_CLUE, |
| 101 | COL_USER, |
| 102 | COL_HIGHLIGHT, |
| 103 | NCOLOURS |
| 104 | }; |
| 105 | |
| 106 | struct game_params { |
| 107 | int c, r, symm; |
| 108 | }; |
| 109 | |
| 110 | struct game_state { |
| 111 | int c, r; |
| 112 | digit *grid; |
| 113 | unsigned char *immutable; /* marks which digits are clues */ |
| 114 | int completed; |
| 115 | }; |
| 116 | |
| 117 | static game_params *default_params(void) |
| 118 | { |
| 119 | game_params *ret = snew(game_params); |
| 120 | |
| 121 | ret->c = ret->r = 3; |
| 122 | ret->symm = SYMM_ROT2; /* a plausible default */ |
| 123 | |
| 124 | return ret; |
| 125 | } |
| 126 | |
| 127 | static int game_fetch_preset(int i, char **name, game_params **params) |
| 128 | { |
| 129 | game_params *ret; |
| 130 | int c, r; |
| 131 | char buf[80]; |
| 132 | |
| 133 | switch (i) { |
| 134 | case 0: c = 2, r = 2; break; |
| 135 | case 1: c = 2, r = 3; break; |
| 136 | case 2: c = 3, r = 3; break; |
| 137 | case 3: c = 3, r = 4; break; |
| 138 | case 4: c = 4, r = 4; break; |
| 139 | default: return FALSE; |
| 140 | } |
| 141 | |
| 142 | sprintf(buf, "%dx%d", c, r); |
| 143 | *name = dupstr(buf); |
| 144 | *params = ret = snew(game_params); |
| 145 | ret->c = c; |
| 146 | ret->r = r; |
| 147 | ret->symm = SYMM_ROT2; |
| 148 | /* FIXME: difficulty presets? */ |
| 149 | return TRUE; |
| 150 | } |
| 151 | |
| 152 | static void free_params(game_params *params) |
| 153 | { |
| 154 | sfree(params); |
| 155 | } |
| 156 | |
| 157 | static game_params *dup_params(game_params *params) |
| 158 | { |
| 159 | game_params *ret = snew(game_params); |
| 160 | *ret = *params; /* structure copy */ |
| 161 | return ret; |
| 162 | } |
| 163 | |
| 164 | static game_params *decode_params(char const *string) |
| 165 | { |
| 166 | game_params *ret = default_params(); |
| 167 | |
| 168 | ret->c = ret->r = atoi(string); |
| 169 | ret->symm = SYMM_ROT2; |
| 170 | while (*string && isdigit((unsigned char)*string)) string++; |
| 171 | if (*string == 'x') { |
| 172 | string++; |
| 173 | ret->r = atoi(string); |
| 174 | while (*string && isdigit((unsigned char)*string)) string++; |
| 175 | } |
| 176 | if (*string == 'r' || *string == 'm' || *string == 'a') { |
| 177 | int sn, sc; |
| 178 | sc = *string++; |
| 179 | sn = atoi(string); |
| 180 | while (*string && isdigit((unsigned char)*string)) string++; |
| 181 | if (sc == 'm' && sn == 4) |
| 182 | ret->symm = SYMM_REF4; |
| 183 | if (sc == 'r' && sn == 4) |
| 184 | ret->symm = SYMM_ROT4; |
| 185 | if (sc == 'r' && sn == 2) |
| 186 | ret->symm = SYMM_ROT2; |
| 187 | if (sc == 'a') |
| 188 | ret->symm = SYMM_NONE; |
| 189 | } |
| 190 | /* FIXME: difficulty levels */ |
| 191 | |
| 192 | return ret; |
| 193 | } |
| 194 | |
| 195 | static char *encode_params(game_params *params) |
| 196 | { |
| 197 | char str[80]; |
| 198 | |
| 199 | /* |
| 200 | * Symmetry is a game generation preference and hence is left |
| 201 | * out of the encoding. Users can add it back in as they see |
| 202 | * fit. |
| 203 | */ |
| 204 | sprintf(str, "%dx%d", params->c, params->r); |
| 205 | return dupstr(str); |
| 206 | } |
| 207 | |
| 208 | static config_item *game_configure(game_params *params) |
| 209 | { |
| 210 | config_item *ret; |
| 211 | char buf[80]; |
| 212 | |
| 213 | ret = snewn(5, config_item); |
| 214 | |
| 215 | ret[0].name = "Columns of sub-blocks"; |
| 216 | ret[0].type = C_STRING; |
| 217 | sprintf(buf, "%d", params->c); |
| 218 | ret[0].sval = dupstr(buf); |
| 219 | ret[0].ival = 0; |
| 220 | |
| 221 | ret[1].name = "Rows of sub-blocks"; |
| 222 | ret[1].type = C_STRING; |
| 223 | sprintf(buf, "%d", params->r); |
| 224 | ret[1].sval = dupstr(buf); |
| 225 | ret[1].ival = 0; |
| 226 | |
| 227 | ret[2].name = "Symmetry"; |
| 228 | ret[2].type = C_CHOICES; |
| 229 | ret[2].sval = ":None:2-way rotation:4-way rotation:4-way mirror"; |
| 230 | ret[2].ival = params->symm; |
| 231 | |
| 232 | /* |
| 233 | * FIXME: difficulty level. |
| 234 | */ |
| 235 | |
| 236 | ret[3].name = NULL; |
| 237 | ret[3].type = C_END; |
| 238 | ret[3].sval = NULL; |
| 239 | ret[3].ival = 0; |
| 240 | |
| 241 | return ret; |
| 242 | } |
| 243 | |
| 244 | static game_params *custom_params(config_item *cfg) |
| 245 | { |
| 246 | game_params *ret = snew(game_params); |
| 247 | |
| 248 | ret->c = atoi(cfg[0].sval); |
| 249 | ret->r = atoi(cfg[1].sval); |
| 250 | ret->symm = cfg[2].ival; |
| 251 | |
| 252 | return ret; |
| 253 | } |
| 254 | |
| 255 | static char *validate_params(game_params *params) |
| 256 | { |
| 257 | if (params->c < 2 || params->r < 2) |
| 258 | return "Both dimensions must be at least 2"; |
| 259 | if (params->c > ORDER_MAX || params->r > ORDER_MAX) |
| 260 | return "Dimensions greater than "STR(ORDER_MAX)" are not supported"; |
| 261 | return NULL; |
| 262 | } |
| 263 | |
| 264 | /* ---------------------------------------------------------------------- |
| 265 | * Full recursive Solo solver. |
| 266 | * |
| 267 | * The algorithm for this solver is shamelessly copied from a |
| 268 | * Python solver written by Andrew Wilkinson (which is GPLed, but |
| 269 | * I've reused only ideas and no code). It mostly just does the |
| 270 | * obvious recursive thing: pick an empty square, put one of the |
| 271 | * possible digits in it, recurse until all squares are filled, |
| 272 | * backtrack and change some choices if necessary. |
| 273 | * |
| 274 | * The clever bit is that every time it chooses which square to |
| 275 | * fill in next, it does so by counting the number of _possible_ |
| 276 | * numbers that can go in each square, and it prioritises so that |
| 277 | * it picks a square with the _lowest_ number of possibilities. The |
| 278 | * idea is that filling in lots of the obvious bits (particularly |
| 279 | * any squares with only one possibility) will cut down on the list |
| 280 | * of possibilities for other squares and hence reduce the enormous |
| 281 | * search space as much as possible as early as possible. |
| 282 | * |
| 283 | * In practice the algorithm appeared to work very well; run on |
| 284 | * sample problems from the Times it completed in well under a |
| 285 | * second on my G5 even when written in Python, and given an empty |
| 286 | * grid (so that in principle it would enumerate _all_ solved |
| 287 | * grids!) it found the first valid solution just as quickly. So |
| 288 | * with a bit more randomisation I see no reason not to use this as |
| 289 | * my grid generator. |
| 290 | */ |
| 291 | |
| 292 | /* |
| 293 | * Internal data structure used in solver to keep track of |
| 294 | * progress. |
| 295 | */ |
| 296 | struct rsolve_coord { int x, y, r; }; |
| 297 | struct rsolve_usage { |
| 298 | int c, r, cr; /* cr == c*r */ |
| 299 | /* grid is a copy of the input grid, modified as we go along */ |
| 300 | digit *grid; |
| 301 | /* row[y*cr+n-1] TRUE if digit n has been placed in row y */ |
| 302 | unsigned char *row; |
| 303 | /* col[x*cr+n-1] TRUE if digit n has been placed in row x */ |
| 304 | unsigned char *col; |
| 305 | /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */ |
| 306 | unsigned char *blk; |
| 307 | /* This lists all the empty spaces remaining in the grid. */ |
| 308 | struct rsolve_coord *spaces; |
| 309 | int nspaces; |
| 310 | /* If we need randomisation in the solve, this is our random state. */ |
| 311 | random_state *rs; |
| 312 | /* Number of solutions so far found, and maximum number we care about. */ |
| 313 | int solns, maxsolns; |
| 314 | }; |
| 315 | |
| 316 | /* |
| 317 | * The real recursive step in the solving function. |
| 318 | */ |
| 319 | static void rsolve_real(struct rsolve_usage *usage, digit *grid) |
| 320 | { |
| 321 | int c = usage->c, r = usage->r, cr = usage->cr; |
| 322 | int i, j, n, sx, sy, bestm, bestr; |
| 323 | int *digits; |
| 324 | |
| 325 | /* |
| 326 | * Firstly, check for completion! If there are no spaces left |
| 327 | * in the grid, we have a solution. |
| 328 | */ |
| 329 | if (usage->nspaces == 0) { |
| 330 | if (!usage->solns) { |
| 331 | /* |
| 332 | * This is our first solution, so fill in the output grid. |
| 333 | */ |
| 334 | memcpy(grid, usage->grid, cr * cr); |
| 335 | } |
| 336 | usage->solns++; |
| 337 | return; |
| 338 | } |
| 339 | |
| 340 | /* |
| 341 | * Otherwise, there must be at least one space. Find the most |
| 342 | * constrained space, using the `r' field as a tie-breaker. |
| 343 | */ |
| 344 | bestm = cr+1; /* so that any space will beat it */ |
| 345 | bestr = 0; |
| 346 | i = sx = sy = -1; |
| 347 | for (j = 0; j < usage->nspaces; j++) { |
| 348 | int x = usage->spaces[j].x, y = usage->spaces[j].y; |
| 349 | int m; |
| 350 | |
| 351 | /* |
| 352 | * Find the number of digits that could go in this space. |
| 353 | */ |
| 354 | m = 0; |
| 355 | for (n = 0; n < cr; n++) |
| 356 | if (!usage->row[y*cr+n] && !usage->col[x*cr+n] && |
| 357 | !usage->blk[((y/c)*c+(x/r))*cr+n]) |
| 358 | m++; |
| 359 | |
| 360 | if (m < bestm || (m == bestm && usage->spaces[j].r < bestr)) { |
| 361 | bestm = m; |
| 362 | bestr = usage->spaces[j].r; |
| 363 | sx = x; |
| 364 | sy = y; |
| 365 | i = j; |
| 366 | } |
| 367 | } |
| 368 | |
| 369 | /* |
| 370 | * Swap that square into the final place in the spaces array, |
| 371 | * so that decrementing nspaces will remove it from the list. |
| 372 | */ |
| 373 | if (i != usage->nspaces-1) { |
| 374 | struct rsolve_coord t; |
| 375 | t = usage->spaces[usage->nspaces-1]; |
| 376 | usage->spaces[usage->nspaces-1] = usage->spaces[i]; |
| 377 | usage->spaces[i] = t; |
| 378 | } |
| 379 | |
| 380 | /* |
| 381 | * Now we've decided which square to start our recursion at, |
| 382 | * simply go through all possible values, shuffling them |
| 383 | * randomly first if necessary. |
| 384 | */ |
| 385 | digits = snewn(bestm, int); |
| 386 | j = 0; |
| 387 | for (n = 0; n < cr; n++) |
| 388 | if (!usage->row[sy*cr+n] && !usage->col[sx*cr+n] && |
| 389 | !usage->blk[((sy/c)*c+(sx/r))*cr+n]) { |
| 390 | digits[j++] = n+1; |
| 391 | } |
| 392 | |
| 393 | if (usage->rs) { |
| 394 | /* shuffle */ |
| 395 | for (i = j; i > 1; i--) { |
| 396 | int p = random_upto(usage->rs, i); |
| 397 | if (p != i-1) { |
| 398 | int t = digits[p]; |
| 399 | digits[p] = digits[i-1]; |
| 400 | digits[i-1] = t; |
| 401 | } |
| 402 | } |
| 403 | } |
| 404 | |
| 405 | /* And finally, go through the digit list and actually recurse. */ |
| 406 | for (i = 0; i < j; i++) { |
| 407 | n = digits[i]; |
| 408 | |
| 409 | /* Update the usage structure to reflect the placing of this digit. */ |
| 410 | usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = |
| 411 | usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = TRUE; |
| 412 | usage->grid[sy*cr+sx] = n; |
| 413 | usage->nspaces--; |
| 414 | |
| 415 | /* Call the solver recursively. */ |
| 416 | rsolve_real(usage, grid); |
| 417 | |
| 418 | /* |
| 419 | * If we have seen as many solutions as we need, terminate |
| 420 | * all processing immediately. |
| 421 | */ |
| 422 | if (usage->solns >= usage->maxsolns) |
| 423 | break; |
| 424 | |
| 425 | /* Revert the usage structure. */ |
| 426 | usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = |
| 427 | usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = FALSE; |
| 428 | usage->grid[sy*cr+sx] = 0; |
| 429 | usage->nspaces++; |
| 430 | } |
| 431 | |
| 432 | sfree(digits); |
| 433 | } |
| 434 | |
| 435 | /* |
| 436 | * Entry point to solver. You give it dimensions and a starting |
| 437 | * grid, which is simply an array of N^4 digits. In that array, 0 |
| 438 | * means an empty square, and 1..N mean a clue square. |
| 439 | * |
| 440 | * Return value is the number of solutions found; searching will |
| 441 | * stop after the provided `max'. (Thus, you can pass max==1 to |
| 442 | * indicate that you only care about finding _one_ solution, or |
| 443 | * max==2 to indicate that you want to know the difference between |
| 444 | * a unique and non-unique solution.) The input parameter `grid' is |
| 445 | * also filled in with the _first_ (or only) solution found by the |
| 446 | * solver. |
| 447 | */ |
| 448 | static int rsolve(int c, int r, digit *grid, random_state *rs, int max) |
| 449 | { |
| 450 | struct rsolve_usage *usage; |
| 451 | int x, y, cr = c*r; |
| 452 | int ret; |
| 453 | |
| 454 | /* |
| 455 | * Create an rsolve_usage structure. |
| 456 | */ |
| 457 | usage = snew(struct rsolve_usage); |
| 458 | |
| 459 | usage->c = c; |
| 460 | usage->r = r; |
| 461 | usage->cr = cr; |
| 462 | |
| 463 | usage->grid = snewn(cr * cr, digit); |
| 464 | memcpy(usage->grid, grid, cr * cr); |
| 465 | |
| 466 | usage->row = snewn(cr * cr, unsigned char); |
| 467 | usage->col = snewn(cr * cr, unsigned char); |
| 468 | usage->blk = snewn(cr * cr, unsigned char); |
| 469 | memset(usage->row, FALSE, cr * cr); |
| 470 | memset(usage->col, FALSE, cr * cr); |
| 471 | memset(usage->blk, FALSE, cr * cr); |
| 472 | |
| 473 | usage->spaces = snewn(cr * cr, struct rsolve_coord); |
| 474 | usage->nspaces = 0; |
| 475 | |
| 476 | usage->solns = 0; |
| 477 | usage->maxsolns = max; |
| 478 | |
| 479 | usage->rs = rs; |
| 480 | |
| 481 | /* |
| 482 | * Now fill it in with data from the input grid. |
| 483 | */ |
| 484 | for (y = 0; y < cr; y++) { |
| 485 | for (x = 0; x < cr; x++) { |
| 486 | int v = grid[y*cr+x]; |
| 487 | if (v == 0) { |
| 488 | usage->spaces[usage->nspaces].x = x; |
| 489 | usage->spaces[usage->nspaces].y = y; |
| 490 | if (rs) |
| 491 | usage->spaces[usage->nspaces].r = random_bits(rs, 31); |
| 492 | else |
| 493 | usage->spaces[usage->nspaces].r = usage->nspaces; |
| 494 | usage->nspaces++; |
| 495 | } else { |
| 496 | usage->row[y*cr+v-1] = TRUE; |
| 497 | usage->col[x*cr+v-1] = TRUE; |
| 498 | usage->blk[((y/c)*c+(x/r))*cr+v-1] = TRUE; |
| 499 | } |
| 500 | } |
| 501 | } |
| 502 | |
| 503 | /* |
| 504 | * Run the real recursive solving function. |
| 505 | */ |
| 506 | rsolve_real(usage, grid); |
| 507 | ret = usage->solns; |
| 508 | |
| 509 | /* |
| 510 | * Clean up the usage structure now we have our answer. |
| 511 | */ |
| 512 | sfree(usage->spaces); |
| 513 | sfree(usage->blk); |
| 514 | sfree(usage->col); |
| 515 | sfree(usage->row); |
| 516 | sfree(usage->grid); |
| 517 | sfree(usage); |
| 518 | |
| 519 | /* |
| 520 | * And return. |
| 521 | */ |
| 522 | return ret; |
| 523 | } |
| 524 | |
| 525 | /* ---------------------------------------------------------------------- |
| 526 | * End of recursive solver code. |
| 527 | */ |
| 528 | |
| 529 | /* ---------------------------------------------------------------------- |
| 530 | * Less capable non-recursive solver. This one is used to check |
| 531 | * solubility of a grid as we gradually remove numbers from it: by |
| 532 | * verifying a grid using this solver we can ensure it isn't _too_ |
| 533 | * hard (e.g. does not actually require guessing and backtracking). |
| 534 | * |
| 535 | * It supports a variety of specific modes of reasoning. By |
| 536 | * enabling or disabling subsets of these modes we can arrange a |
| 537 | * range of difficulty levels. |
| 538 | */ |
| 539 | |
| 540 | /* |
| 541 | * Modes of reasoning currently supported: |
| 542 | * |
| 543 | * - Positional elimination: a number must go in a particular |
| 544 | * square because all the other empty squares in a given |
| 545 | * row/col/blk are ruled out. |
| 546 | * |
| 547 | * - Numeric elimination: a square must have a particular number |
| 548 | * in because all the other numbers that could go in it are |
| 549 | * ruled out. |
| 550 | * |
| 551 | * More advanced modes of reasoning I'd like to support in future: |
| 552 | * |
| 553 | * - Intersectional elimination: given two domains which overlap |
| 554 | * (hence one must be a block, and the other can be a row or |
| 555 | * col), if the possible locations for a particular number in |
| 556 | * one of the domains can be narrowed down to the overlap, then |
| 557 | * that number can be ruled out everywhere but the overlap in |
| 558 | * the other domain too. |
| 559 | * |
| 560 | * - Setwise numeric elimination: if there is a subset of the |
| 561 | * empty squares within a domain such that the union of the |
| 562 | * possible numbers in that subset has the same size as the |
| 563 | * subset itself, then those numbers can be ruled out everywhere |
| 564 | * else in the domain. (For example, if there are five empty |
| 565 | * squares and the possible numbers in each are 12, 23, 13, 134 |
| 566 | * and 1345, then the first three empty squares form such a |
| 567 | * subset: the numbers 1, 2 and 3 _must_ be in those three |
| 568 | * squares in some permutation, and hence we can deduce none of |
| 569 | * them can be in the fourth or fifth squares.) |
| 570 | */ |
| 571 | |
| 572 | /* |
| 573 | * Within this solver, I'm going to transform all y-coordinates by |
| 574 | * inverting the significance of the block number and the position |
| 575 | * within the block. That is, we will start with the top row of |
| 576 | * each block in order, then the second row of each block in order, |
| 577 | * etc. |
| 578 | * |
| 579 | * This transformation has the enormous advantage that it means |
| 580 | * every row, column _and_ block is described by an arithmetic |
| 581 | * progression of coordinates within the cubic array, so that I can |
| 582 | * use the same very simple function to do blockwise, row-wise and |
| 583 | * column-wise elimination. |
| 584 | */ |
| 585 | #define YTRANS(y) (((y)%c)*r+(y)/c) |
| 586 | #define YUNTRANS(y) (((y)%r)*c+(y)/r) |
| 587 | |
| 588 | struct nsolve_usage { |
| 589 | int c, r, cr; |
| 590 | /* |
| 591 | * We set up a cubic array, indexed by x, y and digit; each |
| 592 | * element of this array is TRUE or FALSE according to whether |
| 593 | * or not that digit _could_ in principle go in that position. |
| 594 | * |
| 595 | * The way to index this array is cube[(x*cr+y)*cr+n-1]. |
| 596 | * y-coordinates in here are transformed. |
| 597 | */ |
| 598 | unsigned char *cube; |
| 599 | /* |
| 600 | * This is the grid in which we write down our final |
| 601 | * deductions. y-coordinates in here are _not_ transformed. |
| 602 | */ |
| 603 | digit *grid; |
| 604 | /* |
| 605 | * Now we keep track, at a slightly higher level, of what we |
| 606 | * have yet to work out, to prevent doing the same deduction |
| 607 | * many times. |
| 608 | */ |
| 609 | /* row[y*cr+n-1] TRUE if digit n has been placed in row y */ |
| 610 | unsigned char *row; |
| 611 | /* col[x*cr+n-1] TRUE if digit n has been placed in row x */ |
| 612 | unsigned char *col; |
| 613 | /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */ |
| 614 | unsigned char *blk; |
| 615 | }; |
| 616 | #define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1) |
| 617 | #define cube(x,y,n) (usage->cube[cubepos(x,y,n)]) |
| 618 | |
| 619 | /* |
| 620 | * Function called when we are certain that a particular square has |
| 621 | * a particular number in it. The y-coordinate passed in here is |
| 622 | * transformed. |
| 623 | */ |
| 624 | static void nsolve_place(struct nsolve_usage *usage, int x, int y, int n) |
| 625 | { |
| 626 | int c = usage->c, r = usage->r, cr = usage->cr; |
| 627 | int i, j, bx, by; |
| 628 | |
| 629 | assert(cube(x,y,n)); |
| 630 | |
| 631 | /* |
| 632 | * Rule out all other numbers in this square. |
| 633 | */ |
| 634 | for (i = 1; i <= cr; i++) |
| 635 | if (i != n) |
| 636 | cube(x,y,i) = FALSE; |
| 637 | |
| 638 | /* |
| 639 | * Rule out this number in all other positions in the row. |
| 640 | */ |
| 641 | for (i = 0; i < cr; i++) |
| 642 | if (i != y) |
| 643 | cube(x,i,n) = FALSE; |
| 644 | |
| 645 | /* |
| 646 | * Rule out this number in all other positions in the column. |
| 647 | */ |
| 648 | for (i = 0; i < cr; i++) |
| 649 | if (i != x) |
| 650 | cube(i,y,n) = FALSE; |
| 651 | |
| 652 | /* |
| 653 | * Rule out this number in all other positions in the block. |
| 654 | */ |
| 655 | bx = (x/r)*r; |
| 656 | by = y % r; |
| 657 | for (i = 0; i < r; i++) |
| 658 | for (j = 0; j < c; j++) |
| 659 | if (bx+i != x || by+j*r != y) |
| 660 | cube(bx+i,by+j*r,n) = FALSE; |
| 661 | |
| 662 | /* |
| 663 | * Enter the number in the result grid. |
| 664 | */ |
| 665 | usage->grid[YUNTRANS(y)*cr+x] = n; |
| 666 | |
| 667 | /* |
| 668 | * Cross out this number from the list of numbers left to place |
| 669 | * in its row, its column and its block. |
| 670 | */ |
| 671 | usage->row[y*cr+n-1] = usage->col[x*cr+n-1] = |
| 672 | usage->blk[((y/c)*c+(x/r))*cr+n-1] = TRUE; |
| 673 | } |
| 674 | |
| 675 | static int nsolve_elim(struct nsolve_usage *usage, int start, int step) |
| 676 | { |
| 677 | int c = usage->c, r = usage->r, cr = c*r; |
| 678 | int fpos, m, i; |
| 679 | |
| 680 | /* |
| 681 | * Count the number of set bits within this section of the |
| 682 | * cube. |
| 683 | */ |
| 684 | m = 0; |
| 685 | fpos = -1; |
| 686 | for (i = 0; i < cr; i++) |
| 687 | if (usage->cube[start+i*step]) { |
| 688 | fpos = start+i*step; |
| 689 | m++; |
| 690 | } |
| 691 | |
| 692 | if (m == 1) { |
| 693 | int x, y, n; |
| 694 | assert(fpos >= 0); |
| 695 | |
| 696 | n = 1 + fpos % cr; |
| 697 | y = fpos / cr; |
| 698 | x = y / cr; |
| 699 | y %= cr; |
| 700 | |
| 701 | nsolve_place(usage, x, y, n); |
| 702 | return TRUE; |
| 703 | } |
| 704 | |
| 705 | return FALSE; |
| 706 | } |
| 707 | |
| 708 | static int nsolve(int c, int r, digit *grid) |
| 709 | { |
| 710 | struct nsolve_usage *usage; |
| 711 | int cr = c*r; |
| 712 | int x, y, n; |
| 713 | |
| 714 | /* |
| 715 | * Set up a usage structure as a clean slate (everything |
| 716 | * possible). |
| 717 | */ |
| 718 | usage = snew(struct nsolve_usage); |
| 719 | usage->c = c; |
| 720 | usage->r = r; |
| 721 | usage->cr = cr; |
| 722 | usage->cube = snewn(cr*cr*cr, unsigned char); |
| 723 | usage->grid = grid; /* write straight back to the input */ |
| 724 | memset(usage->cube, TRUE, cr*cr*cr); |
| 725 | |
| 726 | usage->row = snewn(cr * cr, unsigned char); |
| 727 | usage->col = snewn(cr * cr, unsigned char); |
| 728 | usage->blk = snewn(cr * cr, unsigned char); |
| 729 | memset(usage->row, FALSE, cr * cr); |
| 730 | memset(usage->col, FALSE, cr * cr); |
| 731 | memset(usage->blk, FALSE, cr * cr); |
| 732 | |
| 733 | /* |
| 734 | * Place all the clue numbers we are given. |
| 735 | */ |
| 736 | for (x = 0; x < cr; x++) |
| 737 | for (y = 0; y < cr; y++) |
| 738 | if (grid[y*cr+x]) |
| 739 | nsolve_place(usage, x, YTRANS(y), grid[y*cr+x]); |
| 740 | |
| 741 | /* |
| 742 | * Now loop over the grid repeatedly trying all permitted modes |
| 743 | * of reasoning. The loop terminates if we complete an |
| 744 | * iteration without making any progress; we then return |
| 745 | * failure or success depending on whether the grid is full or |
| 746 | * not. |
| 747 | */ |
| 748 | while (1) { |
| 749 | /* |
| 750 | * Blockwise positional elimination. |
| 751 | */ |
| 752 | for (x = 0; x < cr; x += r) |
| 753 | for (y = 0; y < r; y++) |
| 754 | for (n = 1; n <= cr; n++) |
| 755 | if (!usage->blk[(y*c+(x/r))*cr+n-1] && |
| 756 | nsolve_elim(usage, cubepos(x,y,n), r*cr)) |
| 757 | continue; |
| 758 | |
| 759 | /* |
| 760 | * Row-wise positional elimination. |
| 761 | */ |
| 762 | for (y = 0; y < cr; y++) |
| 763 | for (n = 1; n <= cr; n++) |
| 764 | if (!usage->row[y*cr+n-1] && |
| 765 | nsolve_elim(usage, cubepos(0,y,n), cr*cr)) |
| 766 | continue; |
| 767 | /* |
| 768 | * Column-wise positional elimination. |
| 769 | */ |
| 770 | for (x = 0; x < cr; x++) |
| 771 | for (n = 1; n <= cr; n++) |
| 772 | if (!usage->col[x*cr+n-1] && |
| 773 | nsolve_elim(usage, cubepos(x,0,n), cr)) |
| 774 | continue; |
| 775 | |
| 776 | /* |
| 777 | * Numeric elimination. |
| 778 | */ |
| 779 | for (x = 0; x < cr; x++) |
| 780 | for (y = 0; y < cr; y++) |
| 781 | if (!usage->grid[YUNTRANS(y)*cr+x] && |
| 782 | nsolve_elim(usage, cubepos(x,y,1), 1)) |
| 783 | continue; |
| 784 | |
| 785 | /* |
| 786 | * If we reach here, we have made no deductions in this |
| 787 | * iteration, so the algorithm terminates. |
| 788 | */ |
| 789 | break; |
| 790 | } |
| 791 | |
| 792 | sfree(usage->cube); |
| 793 | sfree(usage->row); |
| 794 | sfree(usage->col); |
| 795 | sfree(usage->blk); |
| 796 | sfree(usage); |
| 797 | |
| 798 | for (x = 0; x < cr; x++) |
| 799 | for (y = 0; y < cr; y++) |
| 800 | if (!grid[y*cr+x]) |
| 801 | return FALSE; |
| 802 | return TRUE; |
| 803 | } |
| 804 | |
| 805 | /* ---------------------------------------------------------------------- |
| 806 | * End of non-recursive solver code. |
| 807 | */ |
| 808 | |
| 809 | /* |
| 810 | * Check whether a grid contains a valid complete puzzle. |
| 811 | */ |
| 812 | static int check_valid(int c, int r, digit *grid) |
| 813 | { |
| 814 | int cr = c*r; |
| 815 | unsigned char *used; |
| 816 | int x, y, n; |
| 817 | |
| 818 | used = snewn(cr, unsigned char); |
| 819 | |
| 820 | /* |
| 821 | * Check that each row contains precisely one of everything. |
| 822 | */ |
| 823 | for (y = 0; y < cr; y++) { |
| 824 | memset(used, FALSE, cr); |
| 825 | for (x = 0; x < cr; x++) |
| 826 | if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr) |
| 827 | used[grid[y*cr+x]-1] = TRUE; |
| 828 | for (n = 0; n < cr; n++) |
| 829 | if (!used[n]) { |
| 830 | sfree(used); |
| 831 | return FALSE; |
| 832 | } |
| 833 | } |
| 834 | |
| 835 | /* |
| 836 | * Check that each column contains precisely one of everything. |
| 837 | */ |
| 838 | for (x = 0; x < cr; x++) { |
| 839 | memset(used, FALSE, cr); |
| 840 | for (y = 0; y < cr; y++) |
| 841 | if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr) |
| 842 | used[grid[y*cr+x]-1] = TRUE; |
| 843 | for (n = 0; n < cr; n++) |
| 844 | if (!used[n]) { |
| 845 | sfree(used); |
| 846 | return FALSE; |
| 847 | } |
| 848 | } |
| 849 | |
| 850 | /* |
| 851 | * Check that each block contains precisely one of everything. |
| 852 | */ |
| 853 | for (x = 0; x < cr; x += r) { |
| 854 | for (y = 0; y < cr; y += c) { |
| 855 | int xx, yy; |
| 856 | memset(used, FALSE, cr); |
| 857 | for (xx = x; xx < x+r; xx++) |
| 858 | for (yy = 0; yy < y+c; yy++) |
| 859 | if (grid[yy*cr+xx] > 0 && grid[yy*cr+xx] <= cr) |
| 860 | used[grid[yy*cr+xx]-1] = TRUE; |
| 861 | for (n = 0; n < cr; n++) |
| 862 | if (!used[n]) { |
| 863 | sfree(used); |
| 864 | return FALSE; |
| 865 | } |
| 866 | } |
| 867 | } |
| 868 | |
| 869 | sfree(used); |
| 870 | return TRUE; |
| 871 | } |
| 872 | |
| 873 | static void symmetry_limit(game_params *params, int *xlim, int *ylim, int s) |
| 874 | { |
| 875 | int c = params->c, r = params->r, cr = c*r; |
| 876 | |
| 877 | switch (s) { |
| 878 | case SYMM_NONE: |
| 879 | *xlim = *ylim = cr; |
| 880 | break; |
| 881 | case SYMM_ROT2: |
| 882 | *xlim = (cr+1) / 2; |
| 883 | *ylim = cr; |
| 884 | break; |
| 885 | case SYMM_REF4: |
| 886 | case SYMM_ROT4: |
| 887 | *xlim = *ylim = (cr+1) / 2; |
| 888 | break; |
| 889 | } |
| 890 | } |
| 891 | |
| 892 | static int symmetries(game_params *params, int x, int y, int *output, int s) |
| 893 | { |
| 894 | int c = params->c, r = params->r, cr = c*r; |
| 895 | int i = 0; |
| 896 | |
| 897 | *output++ = x; |
| 898 | *output++ = y; |
| 899 | i++; |
| 900 | |
| 901 | switch (s) { |
| 902 | case SYMM_NONE: |
| 903 | break; /* just x,y is all we need */ |
| 904 | case SYMM_REF4: |
| 905 | case SYMM_ROT4: |
| 906 | switch (s) { |
| 907 | case SYMM_REF4: |
| 908 | *output++ = cr - 1 - x; |
| 909 | *output++ = y; |
| 910 | i++; |
| 911 | |
| 912 | *output++ = x; |
| 913 | *output++ = cr - 1 - y; |
| 914 | i++; |
| 915 | break; |
| 916 | case SYMM_ROT4: |
| 917 | *output++ = cr - 1 - y; |
| 918 | *output++ = x; |
| 919 | i++; |
| 920 | |
| 921 | *output++ = y; |
| 922 | *output++ = cr - 1 - x; |
| 923 | i++; |
| 924 | break; |
| 925 | } |
| 926 | /* fall through */ |
| 927 | case SYMM_ROT2: |
| 928 | *output++ = cr - 1 - x; |
| 929 | *output++ = cr - 1 - y; |
| 930 | i++; |
| 931 | break; |
| 932 | } |
| 933 | |
| 934 | return i; |
| 935 | } |
| 936 | |
| 937 | static char *new_game_seed(game_params *params, random_state *rs) |
| 938 | { |
| 939 | int c = params->c, r = params->r, cr = c*r; |
| 940 | int area = cr*cr; |
| 941 | digit *grid, *grid2; |
| 942 | struct xy { int x, y; } *locs; |
| 943 | int nlocs; |
| 944 | int ret; |
| 945 | char *seed; |
| 946 | int coords[16], ncoords; |
| 947 | int xlim, ylim; |
| 948 | |
| 949 | /* |
| 950 | * Start the recursive solver with an empty grid to generate a |
| 951 | * random solved state. |
| 952 | */ |
| 953 | grid = snewn(area, digit); |
| 954 | memset(grid, 0, area); |
| 955 | ret = rsolve(c, r, grid, rs, 1); |
| 956 | assert(ret == 1); |
| 957 | assert(check_valid(c, r, grid)); |
| 958 | |
| 959 | #ifdef DEBUG |
| 960 | memcpy(grid, |
| 961 | "\x0\x1\x0\x0\x6\x0\x0\x0\x0" |
| 962 | "\x5\x0\x0\x7\x0\x4\x0\x2\x0" |
| 963 | "\x0\x0\x6\x1\x0\x0\x0\x0\x0" |
| 964 | "\x8\x9\x7\x0\x0\x0\x0\x0\x0" |
| 965 | "\x0\x0\x3\x0\x4\x0\x9\x0\x0" |
| 966 | "\x0\x0\x0\x0\x0\x0\x8\x7\x6" |
| 967 | "\x0\x0\x0\x0\x0\x9\x1\x0\x0" |
| 968 | "\x0\x3\x0\x6\x0\x5\x0\x0\x7" |
| 969 | "\x0\x0\x0\x0\x8\x0\x0\x5\x0" |
| 970 | , area); |
| 971 | |
| 972 | { |
| 973 | int y, x; |
| 974 | for (y = 0; y < cr; y++) { |
| 975 | for (x = 0; x < cr; x++) { |
| 976 | printf("%2.0d", grid[y*cr+x]); |
| 977 | } |
| 978 | printf("\n"); |
| 979 | } |
| 980 | printf("\n"); |
| 981 | } |
| 982 | |
| 983 | nsolve(c, r, grid); |
| 984 | |
| 985 | { |
| 986 | int y, x; |
| 987 | for (y = 0; y < cr; y++) { |
| 988 | for (x = 0; x < cr; x++) { |
| 989 | printf("%2.0d", grid[y*cr+x]); |
| 990 | } |
| 991 | printf("\n"); |
| 992 | } |
| 993 | printf("\n"); |
| 994 | } |
| 995 | #endif |
| 996 | |
| 997 | /* |
| 998 | * Now we have a solved grid, start removing things from it |
| 999 | * while preserving solubility. |
| 1000 | */ |
| 1001 | locs = snewn(area, struct xy); |
| 1002 | grid2 = snewn(area, digit); |
| 1003 | symmetry_limit(params, &xlim, &ylim, params->symm); |
| 1004 | while (1) { |
| 1005 | int x, y, i, j; |
| 1006 | |
| 1007 | /* |
| 1008 | * Iterate over the grid and enumerate all the filled |
| 1009 | * squares we could empty. |
| 1010 | */ |
| 1011 | nlocs = 0; |
| 1012 | |
| 1013 | for (x = 0; x < xlim; x++) |
| 1014 | for (y = 0; y < ylim; y++) |
| 1015 | if (grid[y*cr+x]) { |
| 1016 | locs[nlocs].x = x; |
| 1017 | locs[nlocs].y = y; |
| 1018 | nlocs++; |
| 1019 | } |
| 1020 | |
| 1021 | /* |
| 1022 | * Now shuffle that list. |
| 1023 | */ |
| 1024 | for (i = nlocs; i > 1; i--) { |
| 1025 | int p = random_upto(rs, i); |
| 1026 | if (p != i-1) { |
| 1027 | struct xy t = locs[p]; |
| 1028 | locs[p] = locs[i-1]; |
| 1029 | locs[i-1] = t; |
| 1030 | } |
| 1031 | } |
| 1032 | |
| 1033 | /* |
| 1034 | * Now loop over the shuffled list and, for each element, |
| 1035 | * see whether removing that element (and its reflections) |
| 1036 | * from the grid will still leave the grid soluble by |
| 1037 | * nsolve. |
| 1038 | */ |
| 1039 | for (i = 0; i < nlocs; i++) { |
| 1040 | x = locs[i].x; |
| 1041 | y = locs[i].y; |
| 1042 | |
| 1043 | memcpy(grid2, grid, area); |
| 1044 | ncoords = symmetries(params, x, y, coords, params->symm); |
| 1045 | for (j = 0; j < ncoords; j++) |
| 1046 | grid2[coords[2*j+1]*cr+coords[2*j]] = 0; |
| 1047 | |
| 1048 | if (nsolve(c, r, grid2)) { |
| 1049 | for (j = 0; j < ncoords; j++) |
| 1050 | grid[coords[2*j+1]*cr+coords[2*j]] = 0; |
| 1051 | break; |
| 1052 | } |
| 1053 | } |
| 1054 | |
| 1055 | if (i == nlocs) { |
| 1056 | /* |
| 1057 | * There was nothing we could remove without destroying |
| 1058 | * solvability. |
| 1059 | */ |
| 1060 | break; |
| 1061 | } |
| 1062 | } |
| 1063 | sfree(grid2); |
| 1064 | sfree(locs); |
| 1065 | |
| 1066 | #ifdef DEBUG |
| 1067 | { |
| 1068 | int y, x; |
| 1069 | for (y = 0; y < cr; y++) { |
| 1070 | for (x = 0; x < cr; x++) { |
| 1071 | printf("%2.0d", grid[y*cr+x]); |
| 1072 | } |
| 1073 | printf("\n"); |
| 1074 | } |
| 1075 | printf("\n"); |
| 1076 | } |
| 1077 | #endif |
| 1078 | |
| 1079 | /* |
| 1080 | * Now we have the grid as it will be presented to the user. |
| 1081 | * Encode it in a game seed. |
| 1082 | */ |
| 1083 | { |
| 1084 | char *p; |
| 1085 | int run, i; |
| 1086 | |
| 1087 | seed = snewn(5 * area, char); |
| 1088 | p = seed; |
| 1089 | run = 0; |
| 1090 | for (i = 0; i <= area; i++) { |
| 1091 | int n = (i < area ? grid[i] : -1); |
| 1092 | |
| 1093 | if (!n) |
| 1094 | run++; |
| 1095 | else { |
| 1096 | if (run) { |
| 1097 | while (run > 0) { |
| 1098 | int c = 'a' - 1 + run; |
| 1099 | if (run > 26) |
| 1100 | c = 'z'; |
| 1101 | *p++ = c; |
| 1102 | run -= c - ('a' - 1); |
| 1103 | } |
| 1104 | } else { |
| 1105 | /* |
| 1106 | * If there's a number in the very top left or |
| 1107 | * bottom right, there's no point putting an |
| 1108 | * unnecessary _ before or after it. |
| 1109 | */ |
| 1110 | if (p > seed && n > 0) |
| 1111 | *p++ = '_'; |
| 1112 | } |
| 1113 | if (n > 0) |
| 1114 | p += sprintf(p, "%d", n); |
| 1115 | run = 0; |
| 1116 | } |
| 1117 | } |
| 1118 | assert(p - seed < 5 * area); |
| 1119 | *p++ = '\0'; |
| 1120 | seed = sresize(seed, p - seed, char); |
| 1121 | } |
| 1122 | |
| 1123 | sfree(grid); |
| 1124 | |
| 1125 | return seed; |
| 1126 | } |
| 1127 | |
| 1128 | static char *validate_seed(game_params *params, char *seed) |
| 1129 | { |
| 1130 | int area = params->r * params->r * params->c * params->c; |
| 1131 | int squares = 0; |
| 1132 | |
| 1133 | while (*seed) { |
| 1134 | int n = *seed++; |
| 1135 | if (n >= 'a' && n <= 'z') { |
| 1136 | squares += n - 'a' + 1; |
| 1137 | } else if (n == '_') { |
| 1138 | /* do nothing */; |
| 1139 | } else if (n > '0' && n <= '9') { |
| 1140 | squares++; |
| 1141 | while (*seed >= '0' && *seed <= '9') |
| 1142 | seed++; |
| 1143 | } else |
| 1144 | return "Invalid character in game specification"; |
| 1145 | } |
| 1146 | |
| 1147 | if (squares < area) |
| 1148 | return "Not enough data to fill grid"; |
| 1149 | |
| 1150 | if (squares > area) |
| 1151 | return "Too much data to fit in grid"; |
| 1152 | |
| 1153 | return NULL; |
| 1154 | } |
| 1155 | |
| 1156 | static game_state *new_game(game_params *params, char *seed) |
| 1157 | { |
| 1158 | game_state *state = snew(game_state); |
| 1159 | int c = params->c, r = params->r, cr = c*r, area = cr * cr; |
| 1160 | int i; |
| 1161 | |
| 1162 | state->c = params->c; |
| 1163 | state->r = params->r; |
| 1164 | |
| 1165 | state->grid = snewn(area, digit); |
| 1166 | state->immutable = snewn(area, unsigned char); |
| 1167 | memset(state->immutable, FALSE, area); |
| 1168 | |
| 1169 | state->completed = FALSE; |
| 1170 | |
| 1171 | i = 0; |
| 1172 | while (*seed) { |
| 1173 | int n = *seed++; |
| 1174 | if (n >= 'a' && n <= 'z') { |
| 1175 | int run = n - 'a' + 1; |
| 1176 | assert(i + run <= area); |
| 1177 | while (run-- > 0) |
| 1178 | state->grid[i++] = 0; |
| 1179 | } else if (n == '_') { |
| 1180 | /* do nothing */; |
| 1181 | } else if (n > '0' && n <= '9') { |
| 1182 | assert(i < area); |
| 1183 | state->immutable[i] = TRUE; |
| 1184 | state->grid[i++] = atoi(seed-1); |
| 1185 | while (*seed >= '0' && *seed <= '9') |
| 1186 | seed++; |
| 1187 | } else { |
| 1188 | assert(!"We can't get here"); |
| 1189 | } |
| 1190 | } |
| 1191 | assert(i == area); |
| 1192 | |
| 1193 | return state; |
| 1194 | } |
| 1195 | |
| 1196 | static game_state *dup_game(game_state *state) |
| 1197 | { |
| 1198 | game_state *ret = snew(game_state); |
| 1199 | int c = state->c, r = state->r, cr = c*r, area = cr * cr; |
| 1200 | |
| 1201 | ret->c = state->c; |
| 1202 | ret->r = state->r; |
| 1203 | |
| 1204 | ret->grid = snewn(area, digit); |
| 1205 | memcpy(ret->grid, state->grid, area); |
| 1206 | |
| 1207 | ret->immutable = snewn(area, unsigned char); |
| 1208 | memcpy(ret->immutable, state->immutable, area); |
| 1209 | |
| 1210 | ret->completed = state->completed; |
| 1211 | |
| 1212 | return ret; |
| 1213 | } |
| 1214 | |
| 1215 | static void free_game(game_state *state) |
| 1216 | { |
| 1217 | sfree(state->immutable); |
| 1218 | sfree(state->grid); |
| 1219 | sfree(state); |
| 1220 | } |
| 1221 | |
| 1222 | struct game_ui { |
| 1223 | /* |
| 1224 | * These are the coordinates of the currently highlighted |
| 1225 | * square on the grid, or -1,-1 if there isn't one. When there |
| 1226 | * is, pressing a valid number or letter key or Space will |
| 1227 | * enter that number or letter in the grid. |
| 1228 | */ |
| 1229 | int hx, hy; |
| 1230 | }; |
| 1231 | |
| 1232 | static game_ui *new_ui(game_state *state) |
| 1233 | { |
| 1234 | game_ui *ui = snew(game_ui); |
| 1235 | |
| 1236 | ui->hx = ui->hy = -1; |
| 1237 | |
| 1238 | return ui; |
| 1239 | } |
| 1240 | |
| 1241 | static void free_ui(game_ui *ui) |
| 1242 | { |
| 1243 | sfree(ui); |
| 1244 | } |
| 1245 | |
| 1246 | static game_state *make_move(game_state *from, game_ui *ui, int x, int y, |
| 1247 | int button) |
| 1248 | { |
| 1249 | int c = from->c, r = from->r, cr = c*r; |
| 1250 | int tx, ty; |
| 1251 | game_state *ret; |
| 1252 | |
| 1253 | tx = (x - BORDER) / TILE_SIZE; |
| 1254 | ty = (y - BORDER) / TILE_SIZE; |
| 1255 | |
| 1256 | if (tx >= 0 && tx < cr && ty >= 0 && ty < cr && button == LEFT_BUTTON) { |
| 1257 | if (tx == ui->hx && ty == ui->hy) { |
| 1258 | ui->hx = ui->hy = -1; |
| 1259 | } else { |
| 1260 | ui->hx = tx; |
| 1261 | ui->hy = ty; |
| 1262 | } |
| 1263 | return from; /* UI activity occurred */ |
| 1264 | } |
| 1265 | |
| 1266 | if (ui->hx != -1 && ui->hy != -1 && |
| 1267 | ((button >= '1' && button <= '9' && button - '0' <= cr) || |
| 1268 | (button >= 'a' && button <= 'z' && button - 'a' + 10 <= cr) || |
| 1269 | (button >= 'A' && button <= 'Z' && button - 'A' + 10 <= cr) || |
| 1270 | button == ' ')) { |
| 1271 | int n = button - '0'; |
| 1272 | if (button >= 'A' && button <= 'Z') |
| 1273 | n = button - 'A' + 10; |
| 1274 | if (button >= 'a' && button <= 'z') |
| 1275 | n = button - 'a' + 10; |
| 1276 | if (button == ' ') |
| 1277 | n = 0; |
| 1278 | |
| 1279 | if (from->immutable[ui->hy*cr+ui->hx]) |
| 1280 | return NULL; /* can't overwrite this square */ |
| 1281 | |
| 1282 | ret = dup_game(from); |
| 1283 | ret->grid[ui->hy*cr+ui->hx] = n; |
| 1284 | ui->hx = ui->hy = -1; |
| 1285 | |
| 1286 | /* |
| 1287 | * We've made a real change to the grid. Check to see |
| 1288 | * if the game has been completed. |
| 1289 | */ |
| 1290 | if (!ret->completed && check_valid(c, r, ret->grid)) { |
| 1291 | ret->completed = TRUE; |
| 1292 | } |
| 1293 | |
| 1294 | return ret; /* made a valid move */ |
| 1295 | } |
| 1296 | |
| 1297 | return NULL; |
| 1298 | } |
| 1299 | |
| 1300 | /* ---------------------------------------------------------------------- |
| 1301 | * Drawing routines. |
| 1302 | */ |
| 1303 | |
| 1304 | struct game_drawstate { |
| 1305 | int started; |
| 1306 | int c, r, cr; |
| 1307 | digit *grid; |
| 1308 | unsigned char *hl; |
| 1309 | }; |
| 1310 | |
| 1311 | #define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1) |
| 1312 | #define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1) |
| 1313 | |
| 1314 | static void game_size(game_params *params, int *x, int *y) |
| 1315 | { |
| 1316 | int c = params->c, r = params->r, cr = c*r; |
| 1317 | |
| 1318 | *x = XSIZE(cr); |
| 1319 | *y = YSIZE(cr); |
| 1320 | } |
| 1321 | |
| 1322 | static float *game_colours(frontend *fe, game_state *state, int *ncolours) |
| 1323 | { |
| 1324 | float *ret = snewn(3 * NCOLOURS, float); |
| 1325 | |
| 1326 | frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]); |
| 1327 | |
| 1328 | ret[COL_GRID * 3 + 0] = 0.0F; |
| 1329 | ret[COL_GRID * 3 + 1] = 0.0F; |
| 1330 | ret[COL_GRID * 3 + 2] = 0.0F; |
| 1331 | |
| 1332 | ret[COL_CLUE * 3 + 0] = 0.0F; |
| 1333 | ret[COL_CLUE * 3 + 1] = 0.0F; |
| 1334 | ret[COL_CLUE * 3 + 2] = 0.0F; |
| 1335 | |
| 1336 | ret[COL_USER * 3 + 0] = 0.0F; |
| 1337 | ret[COL_USER * 3 + 1] = 0.6F * ret[COL_BACKGROUND * 3 + 1]; |
| 1338 | ret[COL_USER * 3 + 2] = 0.0F; |
| 1339 | |
| 1340 | ret[COL_HIGHLIGHT * 3 + 0] = 0.85F * ret[COL_BACKGROUND * 3 + 0]; |
| 1341 | ret[COL_HIGHLIGHT * 3 + 1] = 0.85F * ret[COL_BACKGROUND * 3 + 1]; |
| 1342 | ret[COL_HIGHLIGHT * 3 + 2] = 0.85F * ret[COL_BACKGROUND * 3 + 2]; |
| 1343 | |
| 1344 | *ncolours = NCOLOURS; |
| 1345 | return ret; |
| 1346 | } |
| 1347 | |
| 1348 | static game_drawstate *game_new_drawstate(game_state *state) |
| 1349 | { |
| 1350 | struct game_drawstate *ds = snew(struct game_drawstate); |
| 1351 | int c = state->c, r = state->r, cr = c*r; |
| 1352 | |
| 1353 | ds->started = FALSE; |
| 1354 | ds->c = c; |
| 1355 | ds->r = r; |
| 1356 | ds->cr = cr; |
| 1357 | ds->grid = snewn(cr*cr, digit); |
| 1358 | memset(ds->grid, 0, cr*cr); |
| 1359 | ds->hl = snewn(cr*cr, unsigned char); |
| 1360 | memset(ds->hl, 0, cr*cr); |
| 1361 | |
| 1362 | return ds; |
| 1363 | } |
| 1364 | |
| 1365 | static void game_free_drawstate(game_drawstate *ds) |
| 1366 | { |
| 1367 | sfree(ds->hl); |
| 1368 | sfree(ds->grid); |
| 1369 | sfree(ds); |
| 1370 | } |
| 1371 | |
| 1372 | static void draw_number(frontend *fe, game_drawstate *ds, game_state *state, |
| 1373 | int x, int y, int hl) |
| 1374 | { |
| 1375 | int c = state->c, r = state->r, cr = c*r; |
| 1376 | int tx, ty; |
| 1377 | int cx, cy, cw, ch; |
| 1378 | char str[2]; |
| 1379 | |
| 1380 | if (ds->grid[y*cr+x] == state->grid[y*cr+x] && ds->hl[y*cr+x] == hl) |
| 1381 | return; /* no change required */ |
| 1382 | |
| 1383 | tx = BORDER + x * TILE_SIZE + 2; |
| 1384 | ty = BORDER + y * TILE_SIZE + 2; |
| 1385 | |
| 1386 | cx = tx; |
| 1387 | cy = ty; |
| 1388 | cw = TILE_SIZE-3; |
| 1389 | ch = TILE_SIZE-3; |
| 1390 | |
| 1391 | if (x % r) |
| 1392 | cx--, cw++; |
| 1393 | if ((x+1) % r) |
| 1394 | cw++; |
| 1395 | if (y % c) |
| 1396 | cy--, ch++; |
| 1397 | if ((y+1) % c) |
| 1398 | ch++; |
| 1399 | |
| 1400 | clip(fe, cx, cy, cw, ch); |
| 1401 | |
| 1402 | /* background needs erasing? */ |
| 1403 | if (ds->grid[y*cr+x] || ds->hl[y*cr+x] != hl) |
| 1404 | draw_rect(fe, cx, cy, cw, ch, hl ? COL_HIGHLIGHT : COL_BACKGROUND); |
| 1405 | |
| 1406 | /* new number needs drawing? */ |
| 1407 | if (state->grid[y*cr+x]) { |
| 1408 | str[1] = '\0'; |
| 1409 | str[0] = state->grid[y*cr+x] + '0'; |
| 1410 | if (str[0] > '9') |
| 1411 | str[0] += 'a' - ('9'+1); |
| 1412 | draw_text(fe, tx + TILE_SIZE/2, ty + TILE_SIZE/2, |
| 1413 | FONT_VARIABLE, TILE_SIZE/2, ALIGN_VCENTRE | ALIGN_HCENTRE, |
| 1414 | state->immutable[y*cr+x] ? COL_CLUE : COL_USER, str); |
| 1415 | } |
| 1416 | |
| 1417 | unclip(fe); |
| 1418 | |
| 1419 | draw_update(fe, cx, cy, cw, ch); |
| 1420 | |
| 1421 | ds->grid[y*cr+x] = state->grid[y*cr+x]; |
| 1422 | ds->hl[y*cr+x] = hl; |
| 1423 | } |
| 1424 | |
| 1425 | static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate, |
| 1426 | game_state *state, int dir, game_ui *ui, |
| 1427 | float animtime, float flashtime) |
| 1428 | { |
| 1429 | int c = state->c, r = state->r, cr = c*r; |
| 1430 | int x, y; |
| 1431 | |
| 1432 | if (!ds->started) { |
| 1433 | /* |
| 1434 | * The initial contents of the window are not guaranteed |
| 1435 | * and can vary with front ends. To be on the safe side, |
| 1436 | * all games should start by drawing a big |
| 1437 | * background-colour rectangle covering the whole window. |
| 1438 | */ |
| 1439 | draw_rect(fe, 0, 0, XSIZE(cr), YSIZE(cr), COL_BACKGROUND); |
| 1440 | |
| 1441 | /* |
| 1442 | * Draw the grid. |
| 1443 | */ |
| 1444 | for (x = 0; x <= cr; x++) { |
| 1445 | int thick = (x % r ? 0 : 1); |
| 1446 | draw_rect(fe, BORDER + x*TILE_SIZE - thick, BORDER-1, |
| 1447 | 1+2*thick, cr*TILE_SIZE+3, COL_GRID); |
| 1448 | } |
| 1449 | for (y = 0; y <= cr; y++) { |
| 1450 | int thick = (y % c ? 0 : 1); |
| 1451 | draw_rect(fe, BORDER-1, BORDER + y*TILE_SIZE - thick, |
| 1452 | cr*TILE_SIZE+3, 1+2*thick, COL_GRID); |
| 1453 | } |
| 1454 | } |
| 1455 | |
| 1456 | /* |
| 1457 | * Draw any numbers which need redrawing. |
| 1458 | */ |
| 1459 | for (x = 0; x < cr; x++) { |
| 1460 | for (y = 0; y < cr; y++) { |
| 1461 | draw_number(fe, ds, state, x, y, |
| 1462 | (x == ui->hx && y == ui->hy) || |
| 1463 | (flashtime > 0 && |
| 1464 | (flashtime <= FLASH_TIME/3 || |
| 1465 | flashtime >= FLASH_TIME*2/3))); |
| 1466 | } |
| 1467 | } |
| 1468 | |
| 1469 | /* |
| 1470 | * Update the _entire_ grid if necessary. |
| 1471 | */ |
| 1472 | if (!ds->started) { |
| 1473 | draw_update(fe, 0, 0, XSIZE(cr), YSIZE(cr)); |
| 1474 | ds->started = TRUE; |
| 1475 | } |
| 1476 | } |
| 1477 | |
| 1478 | static float game_anim_length(game_state *oldstate, game_state *newstate, |
| 1479 | int dir) |
| 1480 | { |
| 1481 | return 0.0F; |
| 1482 | } |
| 1483 | |
| 1484 | static float game_flash_length(game_state *oldstate, game_state *newstate, |
| 1485 | int dir) |
| 1486 | { |
| 1487 | if (!oldstate->completed && newstate->completed) |
| 1488 | return FLASH_TIME; |
| 1489 | return 0.0F; |
| 1490 | } |
| 1491 | |
| 1492 | static int game_wants_statusbar(void) |
| 1493 | { |
| 1494 | return FALSE; |
| 1495 | } |
| 1496 | |
| 1497 | #ifdef COMBINED |
| 1498 | #define thegame solo |
| 1499 | #endif |
| 1500 | |
| 1501 | const struct game thegame = { |
| 1502 | "Solo", "games.solo", TRUE, |
| 1503 | default_params, |
| 1504 | game_fetch_preset, |
| 1505 | decode_params, |
| 1506 | encode_params, |
| 1507 | free_params, |
| 1508 | dup_params, |
| 1509 | game_configure, |
| 1510 | custom_params, |
| 1511 | validate_params, |
| 1512 | new_game_seed, |
| 1513 | validate_seed, |
| 1514 | new_game, |
| 1515 | dup_game, |
| 1516 | free_game, |
| 1517 | new_ui, |
| 1518 | free_ui, |
| 1519 | make_move, |
| 1520 | game_size, |
| 1521 | game_colours, |
| 1522 | game_new_drawstate, |
| 1523 | game_free_drawstate, |
| 1524 | game_redraw, |
| 1525 | game_anim_length, |
| 1526 | game_flash_length, |
| 1527 | game_wants_statusbar, |
| 1528 | }; |