| 1 | /* |
| 2 | * solo.c: the number-placing puzzle most popularly known as `Sudoku'. |
| 3 | * |
| 4 | * TODO: |
| 5 | * |
| 6 | * - reports from users are that `Trivial'-mode puzzles are still |
| 7 | * rather hard compared to newspapers' easy ones, so some better |
| 8 | * low-end difficulty grading would be nice |
| 9 | * + it's possible that really easy puzzles always have |
| 10 | * _several_ things you can do, so don't make you hunt too |
| 11 | * hard for the one deduction you can currently make |
| 12 | * + it's also possible that easy puzzles require fewer |
| 13 | * cross-eliminations: perhaps there's a higher incidence of |
| 14 | * things you can deduce by looking only at (say) rows, |
| 15 | * rather than things you have to check both rows and columns |
| 16 | * for |
| 17 | * + but really, what I need to do is find some really easy |
| 18 | * puzzles and _play_ them, to see what's actually easy about |
| 19 | * them |
| 20 | * + while I'm revamping this area, filling in the _last_ |
| 21 | * number in a nearly-full row or column should certainly be |
| 22 | * permitted even at the lowest difficulty level. |
| 23 | * + also Owen noticed that `Basic' grids requiring numeric |
| 24 | * elimination are actually very hard, so I wonder if a |
| 25 | * difficulty gradation between that and positional- |
| 26 | * elimination-only might be in order |
| 27 | * + but it's not good to have _too_ many difficulty levels, or |
| 28 | * it'll take too long to randomly generate a given level. |
| 29 | * |
| 30 | * - it might still be nice to do some prioritisation on the |
| 31 | * removal of numbers from the grid |
| 32 | * + one possibility is to try to minimise the maximum number |
| 33 | * of filled squares in any block, which in particular ought |
| 34 | * to enforce never leaving a completely filled block in the |
| 35 | * puzzle as presented. |
| 36 | * |
| 37 | * - alternative interface modes |
| 38 | * + sudoku.com's Windows program has a palette of possible |
| 39 | * entries; you select a palette entry first and then click |
| 40 | * on the square you want it to go in, thus enabling |
| 41 | * mouse-only play. Useful for PDAs! I don't think it's |
| 42 | * actually incompatible with the current highlight-then-type |
| 43 | * approach: you _either_ highlight a palette entry and then |
| 44 | * click, _or_ you highlight a square and then type. At most |
| 45 | * one thing is ever highlighted at a time, so there's no way |
| 46 | * to confuse the two. |
| 47 | * + then again, I don't actually like sudoku.com's interface; |
| 48 | * it's too much like a paint package whereas I prefer to |
| 49 | * think of Solo as a text editor. |
| 50 | * + another PDA-friendly possibility is a drag interface: |
| 51 | * _drag_ numbers from the palette into the grid squares. |
| 52 | * Thought experiments suggest I'd prefer that to the |
| 53 | * sudoku.com approach, but I haven't actually tried it. |
| 54 | */ |
| 55 | |
| 56 | /* |
| 57 | * Solo puzzles need to be square overall (since each row and each |
| 58 | * column must contain one of every digit), but they need not be |
| 59 | * subdivided the same way internally. I am going to adopt a |
| 60 | * convention whereby I _always_ refer to `r' as the number of rows |
| 61 | * of _big_ divisions, and `c' as the number of columns of _big_ |
| 62 | * divisions. Thus, a 2c by 3r puzzle looks something like this: |
| 63 | * |
| 64 | * 4 5 1 | 2 6 3 |
| 65 | * 6 3 2 | 5 4 1 |
| 66 | * ------+------ (Of course, you can't subdivide it the other way |
| 67 | * 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the |
| 68 | * 3 2 6 | 4 1 5 top left would conflict with the 4 in the second |
| 69 | * ------+------ box down on the left-hand side.) |
| 70 | * 5 1 4 | 3 2 6 |
| 71 | * 2 6 3 | 1 5 4 |
| 72 | * |
| 73 | * The need for a strong naming convention should now be clear: |
| 74 | * each small box is two rows of digits by three columns, while the |
| 75 | * overall puzzle has three rows of small boxes by two columns. So |
| 76 | * I will (hopefully) consistently use `r' to denote the number of |
| 77 | * rows _of small boxes_ (here 3), which is also the number of |
| 78 | * columns of digits in each small box; and `c' vice versa (here |
| 79 | * 2). |
| 80 | * |
| 81 | * I'm also going to choose arbitrarily to list c first wherever |
| 82 | * possible: the above is a 2x3 puzzle, not a 3x2 one. |
| 83 | */ |
| 84 | |
| 85 | #include <stdio.h> |
| 86 | #include <stdlib.h> |
| 87 | #include <string.h> |
| 88 | #include <assert.h> |
| 89 | #include <ctype.h> |
| 90 | #include <math.h> |
| 91 | |
| 92 | #ifdef STANDALONE_SOLVER |
| 93 | #include <stdarg.h> |
| 94 | int solver_show_working, solver_recurse_depth; |
| 95 | #endif |
| 96 | |
| 97 | #include "puzzles.h" |
| 98 | |
| 99 | /* |
| 100 | * To save space, I store digits internally as unsigned char. This |
| 101 | * imposes a hard limit of 255 on the order of the puzzle. Since |
| 102 | * even a 5x5 takes unacceptably long to generate, I don't see this |
| 103 | * as a serious limitation unless something _really_ impressive |
| 104 | * happens in computing technology; but here's a typedef anyway for |
| 105 | * general good practice. |
| 106 | */ |
| 107 | typedef unsigned char digit; |
| 108 | #define ORDER_MAX 255 |
| 109 | |
| 110 | #define PREFERRED_TILE_SIZE 32 |
| 111 | #define TILE_SIZE (ds->tilesize) |
| 112 | #define BORDER (TILE_SIZE / 2) |
| 113 | |
| 114 | #define FLASH_TIME 0.4F |
| 115 | |
| 116 | enum { SYMM_NONE, SYMM_ROT2, SYMM_ROT4, SYMM_REF2, SYMM_REF2D, SYMM_REF4, |
| 117 | SYMM_REF4D, SYMM_REF8 }; |
| 118 | |
| 119 | enum { DIFF_BLOCK, DIFF_SIMPLE, DIFF_INTERSECT, |
| 120 | DIFF_SET, DIFF_RECURSIVE, DIFF_AMBIGUOUS, DIFF_IMPOSSIBLE }; |
| 121 | |
| 122 | enum { |
| 123 | COL_BACKGROUND, |
| 124 | COL_GRID, |
| 125 | COL_CLUE, |
| 126 | COL_USER, |
| 127 | COL_HIGHLIGHT, |
| 128 | COL_ERROR, |
| 129 | COL_PENCIL, |
| 130 | NCOLOURS |
| 131 | }; |
| 132 | |
| 133 | struct game_params { |
| 134 | int c, r, symm, diff; |
| 135 | }; |
| 136 | |
| 137 | struct game_state { |
| 138 | int c, r; |
| 139 | digit *grid; |
| 140 | unsigned char *pencil; /* c*r*c*r elements */ |
| 141 | unsigned char *immutable; /* marks which digits are clues */ |
| 142 | int completed, cheated; |
| 143 | }; |
| 144 | |
| 145 | static game_params *default_params(void) |
| 146 | { |
| 147 | game_params *ret = snew(game_params); |
| 148 | |
| 149 | ret->c = ret->r = 3; |
| 150 | ret->symm = SYMM_ROT2; /* a plausible default */ |
| 151 | ret->diff = DIFF_BLOCK; /* so is this */ |
| 152 | |
| 153 | return ret; |
| 154 | } |
| 155 | |
| 156 | static void free_params(game_params *params) |
| 157 | { |
| 158 | sfree(params); |
| 159 | } |
| 160 | |
| 161 | static game_params *dup_params(game_params *params) |
| 162 | { |
| 163 | game_params *ret = snew(game_params); |
| 164 | *ret = *params; /* structure copy */ |
| 165 | return ret; |
| 166 | } |
| 167 | |
| 168 | static int game_fetch_preset(int i, char **name, game_params **params) |
| 169 | { |
| 170 | static struct { |
| 171 | char *title; |
| 172 | game_params params; |
| 173 | } presets[] = { |
| 174 | { "2x2 Trivial", { 2, 2, SYMM_ROT2, DIFF_BLOCK } }, |
| 175 | { "2x3 Basic", { 2, 3, SYMM_ROT2, DIFF_SIMPLE } }, |
| 176 | { "3x3 Trivial", { 3, 3, SYMM_ROT2, DIFF_BLOCK } }, |
| 177 | { "3x3 Basic", { 3, 3, SYMM_ROT2, DIFF_SIMPLE } }, |
| 178 | { "3x3 Intermediate", { 3, 3, SYMM_ROT2, DIFF_INTERSECT } }, |
| 179 | { "3x3 Advanced", { 3, 3, SYMM_ROT2, DIFF_SET } }, |
| 180 | { "3x3 Unreasonable", { 3, 3, SYMM_ROT2, DIFF_RECURSIVE } }, |
| 181 | #ifndef SLOW_SYSTEM |
| 182 | { "3x4 Basic", { 3, 4, SYMM_ROT2, DIFF_SIMPLE } }, |
| 183 | { "4x4 Basic", { 4, 4, SYMM_ROT2, DIFF_SIMPLE } }, |
| 184 | #endif |
| 185 | }; |
| 186 | |
| 187 | if (i < 0 || i >= lenof(presets)) |
| 188 | return FALSE; |
| 189 | |
| 190 | *name = dupstr(presets[i].title); |
| 191 | *params = dup_params(&presets[i].params); |
| 192 | |
| 193 | return TRUE; |
| 194 | } |
| 195 | |
| 196 | static void decode_params(game_params *ret, char const *string) |
| 197 | { |
| 198 | ret->c = ret->r = atoi(string); |
| 199 | while (*string && isdigit((unsigned char)*string)) string++; |
| 200 | if (*string == 'x') { |
| 201 | string++; |
| 202 | ret->r = atoi(string); |
| 203 | while (*string && isdigit((unsigned char)*string)) string++; |
| 204 | } |
| 205 | while (*string) { |
| 206 | if (*string == 'r' || *string == 'm' || *string == 'a') { |
| 207 | int sn, sc, sd; |
| 208 | sc = *string++; |
| 209 | if (*string == 'd') { |
| 210 | sd = TRUE; |
| 211 | string++; |
| 212 | } else { |
| 213 | sd = FALSE; |
| 214 | } |
| 215 | sn = atoi(string); |
| 216 | while (*string && isdigit((unsigned char)*string)) string++; |
| 217 | if (sc == 'm' && sn == 8) |
| 218 | ret->symm = SYMM_REF8; |
| 219 | if (sc == 'm' && sn == 4) |
| 220 | ret->symm = sd ? SYMM_REF4D : SYMM_REF4; |
| 221 | if (sc == 'm' && sn == 2) |
| 222 | ret->symm = sd ? SYMM_REF2D : SYMM_REF2; |
| 223 | if (sc == 'r' && sn == 4) |
| 224 | ret->symm = SYMM_ROT4; |
| 225 | if (sc == 'r' && sn == 2) |
| 226 | ret->symm = SYMM_ROT2; |
| 227 | if (sc == 'a') |
| 228 | ret->symm = SYMM_NONE; |
| 229 | } else if (*string == 'd') { |
| 230 | string++; |
| 231 | if (*string == 't') /* trivial */ |
| 232 | string++, ret->diff = DIFF_BLOCK; |
| 233 | else if (*string == 'b') /* basic */ |
| 234 | string++, ret->diff = DIFF_SIMPLE; |
| 235 | else if (*string == 'i') /* intermediate */ |
| 236 | string++, ret->diff = DIFF_INTERSECT; |
| 237 | else if (*string == 'a') /* advanced */ |
| 238 | string++, ret->diff = DIFF_SET; |
| 239 | else if (*string == 'u') /* unreasonable */ |
| 240 | string++, ret->diff = DIFF_RECURSIVE; |
| 241 | } else |
| 242 | string++; /* eat unknown character */ |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | static char *encode_params(game_params *params, int full) |
| 247 | { |
| 248 | char str[80]; |
| 249 | |
| 250 | sprintf(str, "%dx%d", params->c, params->r); |
| 251 | if (full) { |
| 252 | switch (params->symm) { |
| 253 | case SYMM_REF8: strcat(str, "m8"); break; |
| 254 | case SYMM_REF4: strcat(str, "m4"); break; |
| 255 | case SYMM_REF4D: strcat(str, "md4"); break; |
| 256 | case SYMM_REF2: strcat(str, "m2"); break; |
| 257 | case SYMM_REF2D: strcat(str, "md2"); break; |
| 258 | case SYMM_ROT4: strcat(str, "r4"); break; |
| 259 | /* case SYMM_ROT2: strcat(str, "r2"); break; [default] */ |
| 260 | case SYMM_NONE: strcat(str, "a"); break; |
| 261 | } |
| 262 | switch (params->diff) { |
| 263 | /* case DIFF_BLOCK: strcat(str, "dt"); break; [default] */ |
| 264 | case DIFF_SIMPLE: strcat(str, "db"); break; |
| 265 | case DIFF_INTERSECT: strcat(str, "di"); break; |
| 266 | case DIFF_SET: strcat(str, "da"); break; |
| 267 | case DIFF_RECURSIVE: strcat(str, "du"); break; |
| 268 | } |
| 269 | } |
| 270 | return dupstr(str); |
| 271 | } |
| 272 | |
| 273 | static config_item *game_configure(game_params *params) |
| 274 | { |
| 275 | config_item *ret; |
| 276 | char buf[80]; |
| 277 | |
| 278 | ret = snewn(5, config_item); |
| 279 | |
| 280 | ret[0].name = "Columns of sub-blocks"; |
| 281 | ret[0].type = C_STRING; |
| 282 | sprintf(buf, "%d", params->c); |
| 283 | ret[0].sval = dupstr(buf); |
| 284 | ret[0].ival = 0; |
| 285 | |
| 286 | ret[1].name = "Rows of sub-blocks"; |
| 287 | ret[1].type = C_STRING; |
| 288 | sprintf(buf, "%d", params->r); |
| 289 | ret[1].sval = dupstr(buf); |
| 290 | ret[1].ival = 0; |
| 291 | |
| 292 | ret[2].name = "Symmetry"; |
| 293 | ret[2].type = C_CHOICES; |
| 294 | ret[2].sval = ":None:2-way rotation:4-way rotation:2-way mirror:" |
| 295 | "2-way diagonal mirror:4-way mirror:4-way diagonal mirror:" |
| 296 | "8-way mirror"; |
| 297 | ret[2].ival = params->symm; |
| 298 | |
| 299 | ret[3].name = "Difficulty"; |
| 300 | ret[3].type = C_CHOICES; |
| 301 | ret[3].sval = ":Trivial:Basic:Intermediate:Advanced:Unreasonable"; |
| 302 | ret[3].ival = params->diff; |
| 303 | |
| 304 | ret[4].name = NULL; |
| 305 | ret[4].type = C_END; |
| 306 | ret[4].sval = NULL; |
| 307 | ret[4].ival = 0; |
| 308 | |
| 309 | return ret; |
| 310 | } |
| 311 | |
| 312 | static game_params *custom_params(config_item *cfg) |
| 313 | { |
| 314 | game_params *ret = snew(game_params); |
| 315 | |
| 316 | ret->c = atoi(cfg[0].sval); |
| 317 | ret->r = atoi(cfg[1].sval); |
| 318 | ret->symm = cfg[2].ival; |
| 319 | ret->diff = cfg[3].ival; |
| 320 | |
| 321 | return ret; |
| 322 | } |
| 323 | |
| 324 | static char *validate_params(game_params *params, int full) |
| 325 | { |
| 326 | if (params->c < 2 || params->r < 2) |
| 327 | return "Both dimensions must be at least 2"; |
| 328 | if (params->c > ORDER_MAX || params->r > ORDER_MAX) |
| 329 | return "Dimensions greater than "STR(ORDER_MAX)" are not supported"; |
| 330 | if ((params->c * params->r) > 36) |
| 331 | return "Unable to support more than 36 distinct symbols in a puzzle"; |
| 332 | return NULL; |
| 333 | } |
| 334 | |
| 335 | /* ---------------------------------------------------------------------- |
| 336 | * Solver. |
| 337 | * |
| 338 | * This solver is used for several purposes: |
| 339 | * + to generate filled grids as the basis for new puzzles (by |
| 340 | * supplying no clue squares at all) |
| 341 | * + to check solubility of a grid as we gradually remove numbers |
| 342 | * from it |
| 343 | * + to solve an externally generated puzzle when the user selects |
| 344 | * `Solve'. |
| 345 | * |
| 346 | * It supports a variety of specific modes of reasoning. By |
| 347 | * enabling or disabling subsets of these modes we can arrange a |
| 348 | * range of difficulty levels. |
| 349 | */ |
| 350 | |
| 351 | /* |
| 352 | * Modes of reasoning currently supported: |
| 353 | * |
| 354 | * - Positional elimination: a number must go in a particular |
| 355 | * square because all the other empty squares in a given |
| 356 | * row/col/blk are ruled out. |
| 357 | * |
| 358 | * - Numeric elimination: a square must have a particular number |
| 359 | * in because all the other numbers that could go in it are |
| 360 | * ruled out. |
| 361 | * |
| 362 | * - Intersectional analysis: given two domains which overlap |
| 363 | * (hence one must be a block, and the other can be a row or |
| 364 | * col), if the possible locations for a particular number in |
| 365 | * one of the domains can be narrowed down to the overlap, then |
| 366 | * that number can be ruled out everywhere but the overlap in |
| 367 | * the other domain too. |
| 368 | * |
| 369 | * - Set elimination: if there is a subset of the empty squares |
| 370 | * within a domain such that the union of the possible numbers |
| 371 | * in that subset has the same size as the subset itself, then |
| 372 | * those numbers can be ruled out everywhere else in the domain. |
| 373 | * (For example, if there are five empty squares and the |
| 374 | * possible numbers in each are 12, 23, 13, 134 and 1345, then |
| 375 | * the first three empty squares form such a subset: the numbers |
| 376 | * 1, 2 and 3 _must_ be in those three squares in some |
| 377 | * permutation, and hence we can deduce none of them can be in |
| 378 | * the fourth or fifth squares.) |
| 379 | * + You can also see this the other way round, concentrating |
| 380 | * on numbers rather than squares: if there is a subset of |
| 381 | * the unplaced numbers within a domain such that the union |
| 382 | * of all their possible positions has the same size as the |
| 383 | * subset itself, then all other numbers can be ruled out for |
| 384 | * those positions. However, it turns out that this is |
| 385 | * exactly equivalent to the first formulation at all times: |
| 386 | * there is a 1-1 correspondence between suitable subsets of |
| 387 | * the unplaced numbers and suitable subsets of the unfilled |
| 388 | * places, found by taking the _complement_ of the union of |
| 389 | * the numbers' possible positions (or the spaces' possible |
| 390 | * contents). |
| 391 | * |
| 392 | * - Recursion. If all else fails, we pick one of the currently |
| 393 | * most constrained empty squares and take a random guess at its |
| 394 | * contents, then continue solving on that basis and see if we |
| 395 | * get any further. |
| 396 | */ |
| 397 | |
| 398 | /* |
| 399 | * Within this solver, I'm going to transform all y-coordinates by |
| 400 | * inverting the significance of the block number and the position |
| 401 | * within the block. That is, we will start with the top row of |
| 402 | * each block in order, then the second row of each block in order, |
| 403 | * etc. |
| 404 | * |
| 405 | * This transformation has the enormous advantage that it means |
| 406 | * every row, column _and_ block is described by an arithmetic |
| 407 | * progression of coordinates within the cubic array, so that I can |
| 408 | * use the same very simple function to do blockwise, row-wise and |
| 409 | * column-wise elimination. |
| 410 | */ |
| 411 | #define YTRANS(y) (((y)%c)*r+(y)/c) |
| 412 | #define YUNTRANS(y) (((y)%r)*c+(y)/r) |
| 413 | |
| 414 | struct solver_usage { |
| 415 | int c, r, cr; |
| 416 | /* |
| 417 | * We set up a cubic array, indexed by x, y and digit; each |
| 418 | * element of this array is TRUE or FALSE according to whether |
| 419 | * or not that digit _could_ in principle go in that position. |
| 420 | * |
| 421 | * The way to index this array is cube[(x*cr+y)*cr+n-1]. |
| 422 | * y-coordinates in here are transformed. |
| 423 | */ |
| 424 | unsigned char *cube; |
| 425 | /* |
| 426 | * This is the grid in which we write down our final |
| 427 | * deductions. y-coordinates in here are _not_ transformed. |
| 428 | */ |
| 429 | digit *grid; |
| 430 | /* |
| 431 | * Now we keep track, at a slightly higher level, of what we |
| 432 | * have yet to work out, to prevent doing the same deduction |
| 433 | * many times. |
| 434 | */ |
| 435 | /* row[y*cr+n-1] TRUE if digit n has been placed in row y */ |
| 436 | unsigned char *row; |
| 437 | /* col[x*cr+n-1] TRUE if digit n has been placed in row x */ |
| 438 | unsigned char *col; |
| 439 | /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */ |
| 440 | unsigned char *blk; |
| 441 | }; |
| 442 | #define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1) |
| 443 | #define cube(x,y,n) (usage->cube[cubepos(x,y,n)]) |
| 444 | |
| 445 | /* |
| 446 | * Function called when we are certain that a particular square has |
| 447 | * a particular number in it. The y-coordinate passed in here is |
| 448 | * transformed. |
| 449 | */ |
| 450 | static void solver_place(struct solver_usage *usage, int x, int y, int n) |
| 451 | { |
| 452 | int c = usage->c, r = usage->r, cr = usage->cr; |
| 453 | int i, j, bx, by; |
| 454 | |
| 455 | assert(cube(x,y,n)); |
| 456 | |
| 457 | /* |
| 458 | * Rule out all other numbers in this square. |
| 459 | */ |
| 460 | for (i = 1; i <= cr; i++) |
| 461 | if (i != n) |
| 462 | cube(x,y,i) = FALSE; |
| 463 | |
| 464 | /* |
| 465 | * Rule out this number in all other positions in the row. |
| 466 | */ |
| 467 | for (i = 0; i < cr; i++) |
| 468 | if (i != y) |
| 469 | cube(x,i,n) = FALSE; |
| 470 | |
| 471 | /* |
| 472 | * Rule out this number in all other positions in the column. |
| 473 | */ |
| 474 | for (i = 0; i < cr; i++) |
| 475 | if (i != x) |
| 476 | cube(i,y,n) = FALSE; |
| 477 | |
| 478 | /* |
| 479 | * Rule out this number in all other positions in the block. |
| 480 | */ |
| 481 | bx = (x/r)*r; |
| 482 | by = y % r; |
| 483 | for (i = 0; i < r; i++) |
| 484 | for (j = 0; j < c; j++) |
| 485 | if (bx+i != x || by+j*r != y) |
| 486 | cube(bx+i,by+j*r,n) = FALSE; |
| 487 | |
| 488 | /* |
| 489 | * Enter the number in the result grid. |
| 490 | */ |
| 491 | usage->grid[YUNTRANS(y)*cr+x] = n; |
| 492 | |
| 493 | /* |
| 494 | * Cross out this number from the list of numbers left to place |
| 495 | * in its row, its column and its block. |
| 496 | */ |
| 497 | usage->row[y*cr+n-1] = usage->col[x*cr+n-1] = |
| 498 | usage->blk[((y%r)*c+(x/r))*cr+n-1] = TRUE; |
| 499 | } |
| 500 | |
| 501 | static int solver_elim(struct solver_usage *usage, int start, int step |
| 502 | #ifdef STANDALONE_SOLVER |
| 503 | , char *fmt, ... |
| 504 | #endif |
| 505 | ) |
| 506 | { |
| 507 | int c = usage->c, r = usage->r, cr = c*r; |
| 508 | int fpos, m, i; |
| 509 | |
| 510 | /* |
| 511 | * Count the number of set bits within this section of the |
| 512 | * cube. |
| 513 | */ |
| 514 | m = 0; |
| 515 | fpos = -1; |
| 516 | for (i = 0; i < cr; i++) |
| 517 | if (usage->cube[start+i*step]) { |
| 518 | fpos = start+i*step; |
| 519 | m++; |
| 520 | } |
| 521 | |
| 522 | if (m == 1) { |
| 523 | int x, y, n; |
| 524 | assert(fpos >= 0); |
| 525 | |
| 526 | n = 1 + fpos % cr; |
| 527 | y = fpos / cr; |
| 528 | x = y / cr; |
| 529 | y %= cr; |
| 530 | |
| 531 | if (!usage->grid[YUNTRANS(y)*cr+x]) { |
| 532 | #ifdef STANDALONE_SOLVER |
| 533 | if (solver_show_working) { |
| 534 | va_list ap; |
| 535 | printf("%*s", solver_recurse_depth*4, ""); |
| 536 | va_start(ap, fmt); |
| 537 | vprintf(fmt, ap); |
| 538 | va_end(ap); |
| 539 | printf(":\n%*s placing %d at (%d,%d)\n", |
| 540 | solver_recurse_depth*4, "", n, 1+x, 1+YUNTRANS(y)); |
| 541 | } |
| 542 | #endif |
| 543 | solver_place(usage, x, y, n); |
| 544 | return +1; |
| 545 | } |
| 546 | } else if (m == 0) { |
| 547 | #ifdef STANDALONE_SOLVER |
| 548 | if (solver_show_working) { |
| 549 | va_list ap; |
| 550 | printf("%*s", solver_recurse_depth*4, ""); |
| 551 | va_start(ap, fmt); |
| 552 | vprintf(fmt, ap); |
| 553 | va_end(ap); |
| 554 | printf(":\n%*s no possibilities available\n", |
| 555 | solver_recurse_depth*4, ""); |
| 556 | } |
| 557 | #endif |
| 558 | return -1; |
| 559 | } |
| 560 | |
| 561 | return 0; |
| 562 | } |
| 563 | |
| 564 | static int solver_intersect(struct solver_usage *usage, |
| 565 | int start1, int step1, int start2, int step2 |
| 566 | #ifdef STANDALONE_SOLVER |
| 567 | , char *fmt, ... |
| 568 | #endif |
| 569 | ) |
| 570 | { |
| 571 | int c = usage->c, r = usage->r, cr = c*r; |
| 572 | int ret, i; |
| 573 | |
| 574 | /* |
| 575 | * Loop over the first domain and see if there's any set bit |
| 576 | * not also in the second. |
| 577 | */ |
| 578 | for (i = 0; i < cr; i++) { |
| 579 | int p = start1+i*step1; |
| 580 | if (usage->cube[p] && |
| 581 | !(p >= start2 && p < start2+cr*step2 && |
| 582 | (p - start2) % step2 == 0)) |
| 583 | return 0; /* there is, so we can't deduce */ |
| 584 | } |
| 585 | |
| 586 | /* |
| 587 | * We have determined that all set bits in the first domain are |
| 588 | * within its overlap with the second. So loop over the second |
| 589 | * domain and remove all set bits that aren't also in that |
| 590 | * overlap; return +1 iff we actually _did_ anything. |
| 591 | */ |
| 592 | ret = 0; |
| 593 | for (i = 0; i < cr; i++) { |
| 594 | int p = start2+i*step2; |
| 595 | if (usage->cube[p] && |
| 596 | !(p >= start1 && p < start1+cr*step1 && (p - start1) % step1 == 0)) |
| 597 | { |
| 598 | #ifdef STANDALONE_SOLVER |
| 599 | if (solver_show_working) { |
| 600 | int px, py, pn; |
| 601 | |
| 602 | if (!ret) { |
| 603 | va_list ap; |
| 604 | printf("%*s", solver_recurse_depth*4, ""); |
| 605 | va_start(ap, fmt); |
| 606 | vprintf(fmt, ap); |
| 607 | va_end(ap); |
| 608 | printf(":\n"); |
| 609 | } |
| 610 | |
| 611 | pn = 1 + p % cr; |
| 612 | py = p / cr; |
| 613 | px = py / cr; |
| 614 | py %= cr; |
| 615 | |
| 616 | printf("%*s ruling out %d at (%d,%d)\n", |
| 617 | solver_recurse_depth*4, "", pn, 1+px, 1+YUNTRANS(py)); |
| 618 | } |
| 619 | #endif |
| 620 | ret = +1; /* we did something */ |
| 621 | usage->cube[p] = 0; |
| 622 | } |
| 623 | } |
| 624 | |
| 625 | return ret; |
| 626 | } |
| 627 | |
| 628 | struct solver_scratch { |
| 629 | unsigned char *grid, *rowidx, *colidx, *set; |
| 630 | }; |
| 631 | |
| 632 | static int solver_set(struct solver_usage *usage, |
| 633 | struct solver_scratch *scratch, |
| 634 | int start, int step1, int step2 |
| 635 | #ifdef STANDALONE_SOLVER |
| 636 | , char *fmt, ... |
| 637 | #endif |
| 638 | ) |
| 639 | { |
| 640 | int c = usage->c, r = usage->r, cr = c*r; |
| 641 | int i, j, n, count; |
| 642 | unsigned char *grid = scratch->grid; |
| 643 | unsigned char *rowidx = scratch->rowidx; |
| 644 | unsigned char *colidx = scratch->colidx; |
| 645 | unsigned char *set = scratch->set; |
| 646 | |
| 647 | /* |
| 648 | * We are passed a cr-by-cr matrix of booleans. Our first job |
| 649 | * is to winnow it by finding any definite placements - i.e. |
| 650 | * any row with a solitary 1 - and discarding that row and the |
| 651 | * column containing the 1. |
| 652 | */ |
| 653 | memset(rowidx, TRUE, cr); |
| 654 | memset(colidx, TRUE, cr); |
| 655 | for (i = 0; i < cr; i++) { |
| 656 | int count = 0, first = -1; |
| 657 | for (j = 0; j < cr; j++) |
| 658 | if (usage->cube[start+i*step1+j*step2]) |
| 659 | first = j, count++; |
| 660 | |
| 661 | /* |
| 662 | * If count == 0, then there's a row with no 1s at all and |
| 663 | * the puzzle is internally inconsistent. However, we ought |
| 664 | * to have caught this already during the simpler reasoning |
| 665 | * methods, so we can safely fail an assertion if we reach |
| 666 | * this point here. |
| 667 | */ |
| 668 | assert(count > 0); |
| 669 | if (count == 1) |
| 670 | rowidx[i] = colidx[first] = FALSE; |
| 671 | } |
| 672 | |
| 673 | /* |
| 674 | * Convert each of rowidx/colidx from a list of 0s and 1s to a |
| 675 | * list of the indices of the 1s. |
| 676 | */ |
| 677 | for (i = j = 0; i < cr; i++) |
| 678 | if (rowidx[i]) |
| 679 | rowidx[j++] = i; |
| 680 | n = j; |
| 681 | for (i = j = 0; i < cr; i++) |
| 682 | if (colidx[i]) |
| 683 | colidx[j++] = i; |
| 684 | assert(n == j); |
| 685 | |
| 686 | /* |
| 687 | * And create the smaller matrix. |
| 688 | */ |
| 689 | for (i = 0; i < n; i++) |
| 690 | for (j = 0; j < n; j++) |
| 691 | grid[i*cr+j] = usage->cube[start+rowidx[i]*step1+colidx[j]*step2]; |
| 692 | |
| 693 | /* |
| 694 | * Having done that, we now have a matrix in which every row |
| 695 | * has at least two 1s in. Now we search to see if we can find |
| 696 | * a rectangle of zeroes (in the set-theoretic sense of |
| 697 | * `rectangle', i.e. a subset of rows crossed with a subset of |
| 698 | * columns) whose width and height add up to n. |
| 699 | */ |
| 700 | |
| 701 | memset(set, 0, n); |
| 702 | count = 0; |
| 703 | while (1) { |
| 704 | /* |
| 705 | * We have a candidate set. If its size is <=1 or >=n-1 |
| 706 | * then we move on immediately. |
| 707 | */ |
| 708 | if (count > 1 && count < n-1) { |
| 709 | /* |
| 710 | * The number of rows we need is n-count. See if we can |
| 711 | * find that many rows which each have a zero in all |
| 712 | * the positions listed in `set'. |
| 713 | */ |
| 714 | int rows = 0; |
| 715 | for (i = 0; i < n; i++) { |
| 716 | int ok = TRUE; |
| 717 | for (j = 0; j < n; j++) |
| 718 | if (set[j] && grid[i*cr+j]) { |
| 719 | ok = FALSE; |
| 720 | break; |
| 721 | } |
| 722 | if (ok) |
| 723 | rows++; |
| 724 | } |
| 725 | |
| 726 | /* |
| 727 | * We expect never to be able to get _more_ than |
| 728 | * n-count suitable rows: this would imply that (for |
| 729 | * example) there are four numbers which between them |
| 730 | * have at most three possible positions, and hence it |
| 731 | * indicates a faulty deduction before this point or |
| 732 | * even a bogus clue. |
| 733 | */ |
| 734 | if (rows > n - count) { |
| 735 | #ifdef STANDALONE_SOLVER |
| 736 | if (solver_show_working) { |
| 737 | va_list ap; |
| 738 | printf("%*s", solver_recurse_depth*4, |
| 739 | ""); |
| 740 | va_start(ap, fmt); |
| 741 | vprintf(fmt, ap); |
| 742 | va_end(ap); |
| 743 | printf(":\n%*s contradiction reached\n", |
| 744 | solver_recurse_depth*4, ""); |
| 745 | } |
| 746 | #endif |
| 747 | return -1; |
| 748 | } |
| 749 | |
| 750 | if (rows >= n - count) { |
| 751 | int progress = FALSE; |
| 752 | |
| 753 | /* |
| 754 | * We've got one! Now, for each row which _doesn't_ |
| 755 | * satisfy the criterion, eliminate all its set |
| 756 | * bits in the positions _not_ listed in `set'. |
| 757 | * Return +1 (meaning progress has been made) if we |
| 758 | * successfully eliminated anything at all. |
| 759 | * |
| 760 | * This involves referring back through |
| 761 | * rowidx/colidx in order to work out which actual |
| 762 | * positions in the cube to meddle with. |
| 763 | */ |
| 764 | for (i = 0; i < n; i++) { |
| 765 | int ok = TRUE; |
| 766 | for (j = 0; j < n; j++) |
| 767 | if (set[j] && grid[i*cr+j]) { |
| 768 | ok = FALSE; |
| 769 | break; |
| 770 | } |
| 771 | if (!ok) { |
| 772 | for (j = 0; j < n; j++) |
| 773 | if (!set[j] && grid[i*cr+j]) { |
| 774 | int fpos = (start+rowidx[i]*step1+ |
| 775 | colidx[j]*step2); |
| 776 | #ifdef STANDALONE_SOLVER |
| 777 | if (solver_show_working) { |
| 778 | int px, py, pn; |
| 779 | |
| 780 | if (!progress) { |
| 781 | va_list ap; |
| 782 | printf("%*s", solver_recurse_depth*4, |
| 783 | ""); |
| 784 | va_start(ap, fmt); |
| 785 | vprintf(fmt, ap); |
| 786 | va_end(ap); |
| 787 | printf(":\n"); |
| 788 | } |
| 789 | |
| 790 | pn = 1 + fpos % cr; |
| 791 | py = fpos / cr; |
| 792 | px = py / cr; |
| 793 | py %= cr; |
| 794 | |
| 795 | printf("%*s ruling out %d at (%d,%d)\n", |
| 796 | solver_recurse_depth*4, "", |
| 797 | pn, 1+px, 1+YUNTRANS(py)); |
| 798 | } |
| 799 | #endif |
| 800 | progress = TRUE; |
| 801 | usage->cube[fpos] = FALSE; |
| 802 | } |
| 803 | } |
| 804 | } |
| 805 | |
| 806 | if (progress) { |
| 807 | return +1; |
| 808 | } |
| 809 | } |
| 810 | } |
| 811 | |
| 812 | /* |
| 813 | * Binary increment: change the rightmost 0 to a 1, and |
| 814 | * change all 1s to the right of it to 0s. |
| 815 | */ |
| 816 | i = n; |
| 817 | while (i > 0 && set[i-1]) |
| 818 | set[--i] = 0, count--; |
| 819 | if (i > 0) |
| 820 | set[--i] = 1, count++; |
| 821 | else |
| 822 | break; /* done */ |
| 823 | } |
| 824 | |
| 825 | return 0; |
| 826 | } |
| 827 | |
| 828 | static struct solver_scratch *solver_new_scratch(struct solver_usage *usage) |
| 829 | { |
| 830 | struct solver_scratch *scratch = snew(struct solver_scratch); |
| 831 | int cr = usage->cr; |
| 832 | scratch->grid = snewn(cr*cr, unsigned char); |
| 833 | scratch->rowidx = snewn(cr, unsigned char); |
| 834 | scratch->colidx = snewn(cr, unsigned char); |
| 835 | scratch->set = snewn(cr, unsigned char); |
| 836 | return scratch; |
| 837 | } |
| 838 | |
| 839 | static void solver_free_scratch(struct solver_scratch *scratch) |
| 840 | { |
| 841 | sfree(scratch->set); |
| 842 | sfree(scratch->colidx); |
| 843 | sfree(scratch->rowidx); |
| 844 | sfree(scratch->grid); |
| 845 | sfree(scratch); |
| 846 | } |
| 847 | |
| 848 | static int solver(int c, int r, digit *grid, int maxdiff) |
| 849 | { |
| 850 | struct solver_usage *usage; |
| 851 | struct solver_scratch *scratch; |
| 852 | int cr = c*r; |
| 853 | int x, y, n, ret; |
| 854 | int diff = DIFF_BLOCK; |
| 855 | |
| 856 | /* |
| 857 | * Set up a usage structure as a clean slate (everything |
| 858 | * possible). |
| 859 | */ |
| 860 | usage = snew(struct solver_usage); |
| 861 | usage->c = c; |
| 862 | usage->r = r; |
| 863 | usage->cr = cr; |
| 864 | usage->cube = snewn(cr*cr*cr, unsigned char); |
| 865 | usage->grid = grid; /* write straight back to the input */ |
| 866 | memset(usage->cube, TRUE, cr*cr*cr); |
| 867 | |
| 868 | usage->row = snewn(cr * cr, unsigned char); |
| 869 | usage->col = snewn(cr * cr, unsigned char); |
| 870 | usage->blk = snewn(cr * cr, unsigned char); |
| 871 | memset(usage->row, FALSE, cr * cr); |
| 872 | memset(usage->col, FALSE, cr * cr); |
| 873 | memset(usage->blk, FALSE, cr * cr); |
| 874 | |
| 875 | scratch = solver_new_scratch(usage); |
| 876 | |
| 877 | /* |
| 878 | * Place all the clue numbers we are given. |
| 879 | */ |
| 880 | for (x = 0; x < cr; x++) |
| 881 | for (y = 0; y < cr; y++) |
| 882 | if (grid[y*cr+x]) |
| 883 | solver_place(usage, x, YTRANS(y), grid[y*cr+x]); |
| 884 | |
| 885 | /* |
| 886 | * Now loop over the grid repeatedly trying all permitted modes |
| 887 | * of reasoning. The loop terminates if we complete an |
| 888 | * iteration without making any progress; we then return |
| 889 | * failure or success depending on whether the grid is full or |
| 890 | * not. |
| 891 | */ |
| 892 | while (1) { |
| 893 | /* |
| 894 | * I'd like to write `continue;' inside each of the |
| 895 | * following loops, so that the solver returns here after |
| 896 | * making some progress. However, I can't specify that I |
| 897 | * want to continue an outer loop rather than the innermost |
| 898 | * one, so I'm apologetically resorting to a goto. |
| 899 | */ |
| 900 | cont: |
| 901 | |
| 902 | /* |
| 903 | * Blockwise positional elimination. |
| 904 | */ |
| 905 | for (x = 0; x < cr; x += r) |
| 906 | for (y = 0; y < r; y++) |
| 907 | for (n = 1; n <= cr; n++) |
| 908 | if (!usage->blk[(y*c+(x/r))*cr+n-1]) { |
| 909 | ret = solver_elim(usage, cubepos(x,y,n), r*cr |
| 910 | #ifdef STANDALONE_SOLVER |
| 911 | , "positional elimination," |
| 912 | " %d in block (%d,%d)", n, 1+x/r, 1+y |
| 913 | #endif |
| 914 | ); |
| 915 | if (ret < 0) { |
| 916 | diff = DIFF_IMPOSSIBLE; |
| 917 | goto got_result; |
| 918 | } else if (ret > 0) { |
| 919 | diff = max(diff, DIFF_BLOCK); |
| 920 | goto cont; |
| 921 | } |
| 922 | } |
| 923 | |
| 924 | if (maxdiff <= DIFF_BLOCK) |
| 925 | break; |
| 926 | |
| 927 | /* |
| 928 | * Row-wise positional elimination. |
| 929 | */ |
| 930 | for (y = 0; y < cr; y++) |
| 931 | for (n = 1; n <= cr; n++) |
| 932 | if (!usage->row[y*cr+n-1]) { |
| 933 | ret = solver_elim(usage, cubepos(0,y,n), cr*cr |
| 934 | #ifdef STANDALONE_SOLVER |
| 935 | , "positional elimination," |
| 936 | " %d in row %d", n, 1+YUNTRANS(y) |
| 937 | #endif |
| 938 | ); |
| 939 | if (ret < 0) { |
| 940 | diff = DIFF_IMPOSSIBLE; |
| 941 | goto got_result; |
| 942 | } else if (ret > 0) { |
| 943 | diff = max(diff, DIFF_SIMPLE); |
| 944 | goto cont; |
| 945 | } |
| 946 | } |
| 947 | /* |
| 948 | * Column-wise positional elimination. |
| 949 | */ |
| 950 | for (x = 0; x < cr; x++) |
| 951 | for (n = 1; n <= cr; n++) |
| 952 | if (!usage->col[x*cr+n-1]) { |
| 953 | ret = solver_elim(usage, cubepos(x,0,n), cr |
| 954 | #ifdef STANDALONE_SOLVER |
| 955 | , "positional elimination," |
| 956 | " %d in column %d", n, 1+x |
| 957 | #endif |
| 958 | ); |
| 959 | if (ret < 0) { |
| 960 | diff = DIFF_IMPOSSIBLE; |
| 961 | goto got_result; |
| 962 | } else if (ret > 0) { |
| 963 | diff = max(diff, DIFF_SIMPLE); |
| 964 | goto cont; |
| 965 | } |
| 966 | } |
| 967 | |
| 968 | /* |
| 969 | * Numeric elimination. |
| 970 | */ |
| 971 | for (x = 0; x < cr; x++) |
| 972 | for (y = 0; y < cr; y++) |
| 973 | if (!usage->grid[YUNTRANS(y)*cr+x]) { |
| 974 | ret = solver_elim(usage, cubepos(x,y,1), 1 |
| 975 | #ifdef STANDALONE_SOLVER |
| 976 | , "numeric elimination at (%d,%d)", 1+x, |
| 977 | 1+YUNTRANS(y) |
| 978 | #endif |
| 979 | ); |
| 980 | if (ret < 0) { |
| 981 | diff = DIFF_IMPOSSIBLE; |
| 982 | goto got_result; |
| 983 | } else if (ret > 0) { |
| 984 | diff = max(diff, DIFF_SIMPLE); |
| 985 | goto cont; |
| 986 | } |
| 987 | } |
| 988 | |
| 989 | if (maxdiff <= DIFF_SIMPLE) |
| 990 | break; |
| 991 | |
| 992 | /* |
| 993 | * Intersectional analysis, rows vs blocks. |
| 994 | */ |
| 995 | for (y = 0; y < cr; y++) |
| 996 | for (x = 0; x < cr; x += r) |
| 997 | for (n = 1; n <= cr; n++) |
| 998 | /* |
| 999 | * solver_intersect() never returns -1. |
| 1000 | */ |
| 1001 | if (!usage->row[y*cr+n-1] && |
| 1002 | !usage->blk[((y%r)*c+(x/r))*cr+n-1] && |
| 1003 | (solver_intersect(usage, cubepos(0,y,n), cr*cr, |
| 1004 | cubepos(x,y%r,n), r*cr |
| 1005 | #ifdef STANDALONE_SOLVER |
| 1006 | , "intersectional analysis," |
| 1007 | " %d in row %d vs block (%d,%d)", |
| 1008 | n, 1+YUNTRANS(y), 1+x/r, 1+y%r |
| 1009 | #endif |
| 1010 | ) || |
| 1011 | solver_intersect(usage, cubepos(x,y%r,n), r*cr, |
| 1012 | cubepos(0,y,n), cr*cr |
| 1013 | #ifdef STANDALONE_SOLVER |
| 1014 | , "intersectional analysis," |
| 1015 | " %d in block (%d,%d) vs row %d", |
| 1016 | n, 1+x/r, 1+y%r, 1+YUNTRANS(y) |
| 1017 | #endif |
| 1018 | ))) { |
| 1019 | diff = max(diff, DIFF_INTERSECT); |
| 1020 | goto cont; |
| 1021 | } |
| 1022 | |
| 1023 | /* |
| 1024 | * Intersectional analysis, columns vs blocks. |
| 1025 | */ |
| 1026 | for (x = 0; x < cr; x++) |
| 1027 | for (y = 0; y < r; y++) |
| 1028 | for (n = 1; n <= cr; n++) |
| 1029 | if (!usage->col[x*cr+n-1] && |
| 1030 | !usage->blk[(y*c+(x/r))*cr+n-1] && |
| 1031 | (solver_intersect(usage, cubepos(x,0,n), cr, |
| 1032 | cubepos((x/r)*r,y,n), r*cr |
| 1033 | #ifdef STANDALONE_SOLVER |
| 1034 | , "intersectional analysis," |
| 1035 | " %d in column %d vs block (%d,%d)", |
| 1036 | n, 1+x, 1+x/r, 1+y |
| 1037 | #endif |
| 1038 | ) || |
| 1039 | solver_intersect(usage, cubepos((x/r)*r,y,n), r*cr, |
| 1040 | cubepos(x,0,n), cr |
| 1041 | #ifdef STANDALONE_SOLVER |
| 1042 | , "intersectional analysis," |
| 1043 | " %d in block (%d,%d) vs column %d", |
| 1044 | n, 1+x/r, 1+y, 1+x |
| 1045 | #endif |
| 1046 | ))) { |
| 1047 | diff = max(diff, DIFF_INTERSECT); |
| 1048 | goto cont; |
| 1049 | } |
| 1050 | |
| 1051 | if (maxdiff <= DIFF_INTERSECT) |
| 1052 | break; |
| 1053 | |
| 1054 | /* |
| 1055 | * Blockwise set elimination. |
| 1056 | */ |
| 1057 | for (x = 0; x < cr; x += r) |
| 1058 | for (y = 0; y < r; y++) { |
| 1059 | ret = solver_set(usage, scratch, cubepos(x,y,1), r*cr, 1 |
| 1060 | #ifdef STANDALONE_SOLVER |
| 1061 | , "set elimination, block (%d,%d)", 1+x/r, 1+y |
| 1062 | #endif |
| 1063 | ); |
| 1064 | if (ret < 0) { |
| 1065 | diff = DIFF_IMPOSSIBLE; |
| 1066 | goto got_result; |
| 1067 | } else if (ret > 0) { |
| 1068 | diff = max(diff, DIFF_SET); |
| 1069 | goto cont; |
| 1070 | } |
| 1071 | } |
| 1072 | |
| 1073 | /* |
| 1074 | * Row-wise set elimination. |
| 1075 | */ |
| 1076 | for (y = 0; y < cr; y++) { |
| 1077 | ret = solver_set(usage, scratch, cubepos(0,y,1), cr*cr, 1 |
| 1078 | #ifdef STANDALONE_SOLVER |
| 1079 | , "set elimination, row %d", 1+YUNTRANS(y) |
| 1080 | #endif |
| 1081 | ); |
| 1082 | if (ret < 0) { |
| 1083 | diff = DIFF_IMPOSSIBLE; |
| 1084 | goto got_result; |
| 1085 | } else if (ret > 0) { |
| 1086 | diff = max(diff, DIFF_SET); |
| 1087 | goto cont; |
| 1088 | } |
| 1089 | } |
| 1090 | |
| 1091 | /* |
| 1092 | * Column-wise set elimination. |
| 1093 | */ |
| 1094 | for (x = 0; x < cr; x++) { |
| 1095 | ret = solver_set(usage, scratch, cubepos(x,0,1), cr, 1 |
| 1096 | #ifdef STANDALONE_SOLVER |
| 1097 | , "set elimination, column %d", 1+x |
| 1098 | #endif |
| 1099 | ); |
| 1100 | if (ret < 0) { |
| 1101 | diff = DIFF_IMPOSSIBLE; |
| 1102 | goto got_result; |
| 1103 | } else if (ret > 0) { |
| 1104 | diff = max(diff, DIFF_SET); |
| 1105 | goto cont; |
| 1106 | } |
| 1107 | } |
| 1108 | |
| 1109 | /* |
| 1110 | * If we reach here, we have made no deductions in this |
| 1111 | * iteration, so the algorithm terminates. |
| 1112 | */ |
| 1113 | break; |
| 1114 | } |
| 1115 | |
| 1116 | /* |
| 1117 | * Last chance: if we haven't fully solved the puzzle yet, try |
| 1118 | * recursing based on guesses for a particular square. We pick |
| 1119 | * one of the most constrained empty squares we can find, which |
| 1120 | * has the effect of pruning the search tree as much as |
| 1121 | * possible. |
| 1122 | */ |
| 1123 | if (maxdiff >= DIFF_RECURSIVE) { |
| 1124 | int best, bestcount; |
| 1125 | |
| 1126 | best = -1; |
| 1127 | bestcount = cr+1; |
| 1128 | |
| 1129 | for (y = 0; y < cr; y++) |
| 1130 | for (x = 0; x < cr; x++) |
| 1131 | if (!grid[y*cr+x]) { |
| 1132 | int count; |
| 1133 | |
| 1134 | /* |
| 1135 | * An unfilled square. Count the number of |
| 1136 | * possible digits in it. |
| 1137 | */ |
| 1138 | count = 0; |
| 1139 | for (n = 1; n <= cr; n++) |
| 1140 | if (cube(x,YTRANS(y),n)) |
| 1141 | count++; |
| 1142 | |
| 1143 | /* |
| 1144 | * We should have found any impossibilities |
| 1145 | * already, so this can safely be an assert. |
| 1146 | */ |
| 1147 | assert(count > 1); |
| 1148 | |
| 1149 | if (count < bestcount) { |
| 1150 | bestcount = count; |
| 1151 | best = y*cr+x; |
| 1152 | } |
| 1153 | } |
| 1154 | |
| 1155 | if (best != -1) { |
| 1156 | int i, j; |
| 1157 | digit *list, *ingrid, *outgrid; |
| 1158 | |
| 1159 | diff = DIFF_IMPOSSIBLE; /* no solution found yet */ |
| 1160 | |
| 1161 | /* |
| 1162 | * Attempt recursion. |
| 1163 | */ |
| 1164 | y = best / cr; |
| 1165 | x = best % cr; |
| 1166 | |
| 1167 | list = snewn(cr, digit); |
| 1168 | ingrid = snewn(cr * cr, digit); |
| 1169 | outgrid = snewn(cr * cr, digit); |
| 1170 | memcpy(ingrid, grid, cr * cr); |
| 1171 | |
| 1172 | /* Make a list of the possible digits. */ |
| 1173 | for (j = 0, n = 1; n <= cr; n++) |
| 1174 | if (cube(x,YTRANS(y),n)) |
| 1175 | list[j++] = n; |
| 1176 | |
| 1177 | #ifdef STANDALONE_SOLVER |
| 1178 | if (solver_show_working) { |
| 1179 | char *sep = ""; |
| 1180 | printf("%*srecursing on (%d,%d) [", |
| 1181 | solver_recurse_depth*4, "", x, y); |
| 1182 | for (i = 0; i < j; i++) { |
| 1183 | printf("%s%d", sep, list[i]); |
| 1184 | sep = " or "; |
| 1185 | } |
| 1186 | printf("]\n"); |
| 1187 | } |
| 1188 | #endif |
| 1189 | |
| 1190 | /* |
| 1191 | * And step along the list, recursing back into the |
| 1192 | * main solver at every stage. |
| 1193 | */ |
| 1194 | for (i = 0; i < j; i++) { |
| 1195 | int ret; |
| 1196 | |
| 1197 | memcpy(outgrid, ingrid, cr * cr); |
| 1198 | outgrid[y*cr+x] = list[i]; |
| 1199 | |
| 1200 | #ifdef STANDALONE_SOLVER |
| 1201 | if (solver_show_working) |
| 1202 | printf("%*sguessing %d at (%d,%d)\n", |
| 1203 | solver_recurse_depth*4, "", list[i], x, y); |
| 1204 | solver_recurse_depth++; |
| 1205 | #endif |
| 1206 | |
| 1207 | ret = solver(c, r, outgrid, maxdiff); |
| 1208 | |
| 1209 | #ifdef STANDALONE_SOLVER |
| 1210 | solver_recurse_depth--; |
| 1211 | if (solver_show_working) { |
| 1212 | printf("%*sretracting %d at (%d,%d)\n", |
| 1213 | solver_recurse_depth*4, "", list[i], x, y); |
| 1214 | } |
| 1215 | #endif |
| 1216 | |
| 1217 | /* |
| 1218 | * If we have our first solution, copy it into the |
| 1219 | * grid we will return. |
| 1220 | */ |
| 1221 | if (diff == DIFF_IMPOSSIBLE && ret != DIFF_IMPOSSIBLE) |
| 1222 | memcpy(grid, outgrid, cr*cr); |
| 1223 | |
| 1224 | if (ret == DIFF_AMBIGUOUS) |
| 1225 | diff = DIFF_AMBIGUOUS; |
| 1226 | else if (ret == DIFF_IMPOSSIBLE) |
| 1227 | /* do not change our return value */; |
| 1228 | else { |
| 1229 | /* the recursion turned up exactly one solution */ |
| 1230 | if (diff == DIFF_IMPOSSIBLE) |
| 1231 | diff = DIFF_RECURSIVE; |
| 1232 | else |
| 1233 | diff = DIFF_AMBIGUOUS; |
| 1234 | } |
| 1235 | |
| 1236 | /* |
| 1237 | * As soon as we've found more than one solution, |
| 1238 | * give up immediately. |
| 1239 | */ |
| 1240 | if (diff == DIFF_AMBIGUOUS) |
| 1241 | break; |
| 1242 | } |
| 1243 | |
| 1244 | sfree(outgrid); |
| 1245 | sfree(ingrid); |
| 1246 | sfree(list); |
| 1247 | } |
| 1248 | |
| 1249 | } else { |
| 1250 | /* |
| 1251 | * We're forbidden to use recursion, so we just see whether |
| 1252 | * our grid is fully solved, and return DIFF_IMPOSSIBLE |
| 1253 | * otherwise. |
| 1254 | */ |
| 1255 | for (y = 0; y < cr; y++) |
| 1256 | for (x = 0; x < cr; x++) |
| 1257 | if (!grid[y*cr+x]) |
| 1258 | diff = DIFF_IMPOSSIBLE; |
| 1259 | } |
| 1260 | |
| 1261 | got_result:; |
| 1262 | |
| 1263 | #ifdef STANDALONE_SOLVER |
| 1264 | if (solver_show_working) |
| 1265 | printf("%*s%s found\n", |
| 1266 | solver_recurse_depth*4, "", |
| 1267 | diff == DIFF_IMPOSSIBLE ? "no solution" : |
| 1268 | diff == DIFF_AMBIGUOUS ? "multiple solutions" : |
| 1269 | "one solution"); |
| 1270 | #endif |
| 1271 | |
| 1272 | sfree(usage->cube); |
| 1273 | sfree(usage->row); |
| 1274 | sfree(usage->col); |
| 1275 | sfree(usage->blk); |
| 1276 | sfree(usage); |
| 1277 | |
| 1278 | solver_free_scratch(scratch); |
| 1279 | |
| 1280 | return diff; |
| 1281 | } |
| 1282 | |
| 1283 | /* ---------------------------------------------------------------------- |
| 1284 | * End of solver code. |
| 1285 | */ |
| 1286 | |
| 1287 | /* ---------------------------------------------------------------------- |
| 1288 | * Solo filled-grid generator. |
| 1289 | * |
| 1290 | * This grid generator works by essentially trying to solve a grid |
| 1291 | * starting from no clues, and not worrying that there's more than |
| 1292 | * one possible solution. Unfortunately, it isn't computationally |
| 1293 | * feasible to do this by calling the above solver with an empty |
| 1294 | * grid, because that one needs to allocate a lot of scratch space |
| 1295 | * at every recursion level. Instead, I have a much simpler |
| 1296 | * algorithm which I shamelessly copied from a Python solver |
| 1297 | * written by Andrew Wilkinson (which is GPLed, but I've reused |
| 1298 | * only ideas and no code). It mostly just does the obvious |
| 1299 | * recursive thing: pick an empty square, put one of the possible |
| 1300 | * digits in it, recurse until all squares are filled, backtrack |
| 1301 | * and change some choices if necessary. |
| 1302 | * |
| 1303 | * The clever bit is that every time it chooses which square to |
| 1304 | * fill in next, it does so by counting the number of _possible_ |
| 1305 | * numbers that can go in each square, and it prioritises so that |
| 1306 | * it picks a square with the _lowest_ number of possibilities. The |
| 1307 | * idea is that filling in lots of the obvious bits (particularly |
| 1308 | * any squares with only one possibility) will cut down on the list |
| 1309 | * of possibilities for other squares and hence reduce the enormous |
| 1310 | * search space as much as possible as early as possible. |
| 1311 | */ |
| 1312 | |
| 1313 | /* |
| 1314 | * Internal data structure used in gridgen to keep track of |
| 1315 | * progress. |
| 1316 | */ |
| 1317 | struct gridgen_coord { int x, y, r; }; |
| 1318 | struct gridgen_usage { |
| 1319 | int c, r, cr; /* cr == c*r */ |
| 1320 | /* grid is a copy of the input grid, modified as we go along */ |
| 1321 | digit *grid; |
| 1322 | /* row[y*cr+n-1] TRUE if digit n has been placed in row y */ |
| 1323 | unsigned char *row; |
| 1324 | /* col[x*cr+n-1] TRUE if digit n has been placed in row x */ |
| 1325 | unsigned char *col; |
| 1326 | /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */ |
| 1327 | unsigned char *blk; |
| 1328 | /* This lists all the empty spaces remaining in the grid. */ |
| 1329 | struct gridgen_coord *spaces; |
| 1330 | int nspaces; |
| 1331 | /* If we need randomisation in the solve, this is our random state. */ |
| 1332 | random_state *rs; |
| 1333 | }; |
| 1334 | |
| 1335 | /* |
| 1336 | * The real recursive step in the generating function. |
| 1337 | */ |
| 1338 | static int gridgen_real(struct gridgen_usage *usage, digit *grid) |
| 1339 | { |
| 1340 | int c = usage->c, r = usage->r, cr = usage->cr; |
| 1341 | int i, j, n, sx, sy, bestm, bestr, ret; |
| 1342 | int *digits; |
| 1343 | |
| 1344 | /* |
| 1345 | * Firstly, check for completion! If there are no spaces left |
| 1346 | * in the grid, we have a solution. |
| 1347 | */ |
| 1348 | if (usage->nspaces == 0) { |
| 1349 | memcpy(grid, usage->grid, cr * cr); |
| 1350 | return TRUE; |
| 1351 | } |
| 1352 | |
| 1353 | /* |
| 1354 | * Otherwise, there must be at least one space. Find the most |
| 1355 | * constrained space, using the `r' field as a tie-breaker. |
| 1356 | */ |
| 1357 | bestm = cr+1; /* so that any space will beat it */ |
| 1358 | bestr = 0; |
| 1359 | i = sx = sy = -1; |
| 1360 | for (j = 0; j < usage->nspaces; j++) { |
| 1361 | int x = usage->spaces[j].x, y = usage->spaces[j].y; |
| 1362 | int m; |
| 1363 | |
| 1364 | /* |
| 1365 | * Find the number of digits that could go in this space. |
| 1366 | */ |
| 1367 | m = 0; |
| 1368 | for (n = 0; n < cr; n++) |
| 1369 | if (!usage->row[y*cr+n] && !usage->col[x*cr+n] && |
| 1370 | !usage->blk[((y/c)*c+(x/r))*cr+n]) |
| 1371 | m++; |
| 1372 | |
| 1373 | if (m < bestm || (m == bestm && usage->spaces[j].r < bestr)) { |
| 1374 | bestm = m; |
| 1375 | bestr = usage->spaces[j].r; |
| 1376 | sx = x; |
| 1377 | sy = y; |
| 1378 | i = j; |
| 1379 | } |
| 1380 | } |
| 1381 | |
| 1382 | /* |
| 1383 | * Swap that square into the final place in the spaces array, |
| 1384 | * so that decrementing nspaces will remove it from the list. |
| 1385 | */ |
| 1386 | if (i != usage->nspaces-1) { |
| 1387 | struct gridgen_coord t; |
| 1388 | t = usage->spaces[usage->nspaces-1]; |
| 1389 | usage->spaces[usage->nspaces-1] = usage->spaces[i]; |
| 1390 | usage->spaces[i] = t; |
| 1391 | } |
| 1392 | |
| 1393 | /* |
| 1394 | * Now we've decided which square to start our recursion at, |
| 1395 | * simply go through all possible values, shuffling them |
| 1396 | * randomly first if necessary. |
| 1397 | */ |
| 1398 | digits = snewn(bestm, int); |
| 1399 | j = 0; |
| 1400 | for (n = 0; n < cr; n++) |
| 1401 | if (!usage->row[sy*cr+n] && !usage->col[sx*cr+n] && |
| 1402 | !usage->blk[((sy/c)*c+(sx/r))*cr+n]) { |
| 1403 | digits[j++] = n+1; |
| 1404 | } |
| 1405 | |
| 1406 | if (usage->rs) |
| 1407 | shuffle(digits, j, sizeof(*digits), usage->rs); |
| 1408 | |
| 1409 | /* And finally, go through the digit list and actually recurse. */ |
| 1410 | ret = FALSE; |
| 1411 | for (i = 0; i < j; i++) { |
| 1412 | n = digits[i]; |
| 1413 | |
| 1414 | /* Update the usage structure to reflect the placing of this digit. */ |
| 1415 | usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = |
| 1416 | usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = TRUE; |
| 1417 | usage->grid[sy*cr+sx] = n; |
| 1418 | usage->nspaces--; |
| 1419 | |
| 1420 | /* Call the solver recursively. Stop when we find a solution. */ |
| 1421 | if (gridgen_real(usage, grid)) |
| 1422 | ret = TRUE; |
| 1423 | |
| 1424 | /* Revert the usage structure. */ |
| 1425 | usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = |
| 1426 | usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = FALSE; |
| 1427 | usage->grid[sy*cr+sx] = 0; |
| 1428 | usage->nspaces++; |
| 1429 | |
| 1430 | if (ret) |
| 1431 | break; |
| 1432 | } |
| 1433 | |
| 1434 | sfree(digits); |
| 1435 | return ret; |
| 1436 | } |
| 1437 | |
| 1438 | /* |
| 1439 | * Entry point to generator. You give it dimensions and a starting |
| 1440 | * grid, which is simply an array of cr*cr digits. |
| 1441 | */ |
| 1442 | static void gridgen(int c, int r, digit *grid, random_state *rs) |
| 1443 | { |
| 1444 | struct gridgen_usage *usage; |
| 1445 | int x, y, cr = c*r; |
| 1446 | |
| 1447 | /* |
| 1448 | * Clear the grid to start with. |
| 1449 | */ |
| 1450 | memset(grid, 0, cr*cr); |
| 1451 | |
| 1452 | /* |
| 1453 | * Create a gridgen_usage structure. |
| 1454 | */ |
| 1455 | usage = snew(struct gridgen_usage); |
| 1456 | |
| 1457 | usage->c = c; |
| 1458 | usage->r = r; |
| 1459 | usage->cr = cr; |
| 1460 | |
| 1461 | usage->grid = snewn(cr * cr, digit); |
| 1462 | memcpy(usage->grid, grid, cr * cr); |
| 1463 | |
| 1464 | usage->row = snewn(cr * cr, unsigned char); |
| 1465 | usage->col = snewn(cr * cr, unsigned char); |
| 1466 | usage->blk = snewn(cr * cr, unsigned char); |
| 1467 | memset(usage->row, FALSE, cr * cr); |
| 1468 | memset(usage->col, FALSE, cr * cr); |
| 1469 | memset(usage->blk, FALSE, cr * cr); |
| 1470 | |
| 1471 | usage->spaces = snewn(cr * cr, struct gridgen_coord); |
| 1472 | usage->nspaces = 0; |
| 1473 | |
| 1474 | usage->rs = rs; |
| 1475 | |
| 1476 | /* |
| 1477 | * Initialise the list of grid spaces. |
| 1478 | */ |
| 1479 | for (y = 0; y < cr; y++) { |
| 1480 | for (x = 0; x < cr; x++) { |
| 1481 | usage->spaces[usage->nspaces].x = x; |
| 1482 | usage->spaces[usage->nspaces].y = y; |
| 1483 | usage->spaces[usage->nspaces].r = random_bits(rs, 31); |
| 1484 | usage->nspaces++; |
| 1485 | } |
| 1486 | } |
| 1487 | |
| 1488 | /* |
| 1489 | * Run the real generator function. |
| 1490 | */ |
| 1491 | gridgen_real(usage, grid); |
| 1492 | |
| 1493 | /* |
| 1494 | * Clean up the usage structure now we have our answer. |
| 1495 | */ |
| 1496 | sfree(usage->spaces); |
| 1497 | sfree(usage->blk); |
| 1498 | sfree(usage->col); |
| 1499 | sfree(usage->row); |
| 1500 | sfree(usage->grid); |
| 1501 | sfree(usage); |
| 1502 | } |
| 1503 | |
| 1504 | /* ---------------------------------------------------------------------- |
| 1505 | * End of grid generator code. |
| 1506 | */ |
| 1507 | |
| 1508 | /* |
| 1509 | * Check whether a grid contains a valid complete puzzle. |
| 1510 | */ |
| 1511 | static int check_valid(int c, int r, digit *grid) |
| 1512 | { |
| 1513 | int cr = c*r; |
| 1514 | unsigned char *used; |
| 1515 | int x, y, n; |
| 1516 | |
| 1517 | used = snewn(cr, unsigned char); |
| 1518 | |
| 1519 | /* |
| 1520 | * Check that each row contains precisely one of everything. |
| 1521 | */ |
| 1522 | for (y = 0; y < cr; y++) { |
| 1523 | memset(used, FALSE, cr); |
| 1524 | for (x = 0; x < cr; x++) |
| 1525 | if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr) |
| 1526 | used[grid[y*cr+x]-1] = TRUE; |
| 1527 | for (n = 0; n < cr; n++) |
| 1528 | if (!used[n]) { |
| 1529 | sfree(used); |
| 1530 | return FALSE; |
| 1531 | } |
| 1532 | } |
| 1533 | |
| 1534 | /* |
| 1535 | * Check that each column contains precisely one of everything. |
| 1536 | */ |
| 1537 | for (x = 0; x < cr; x++) { |
| 1538 | memset(used, FALSE, cr); |
| 1539 | for (y = 0; y < cr; y++) |
| 1540 | if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr) |
| 1541 | used[grid[y*cr+x]-1] = TRUE; |
| 1542 | for (n = 0; n < cr; n++) |
| 1543 | if (!used[n]) { |
| 1544 | sfree(used); |
| 1545 | return FALSE; |
| 1546 | } |
| 1547 | } |
| 1548 | |
| 1549 | /* |
| 1550 | * Check that each block contains precisely one of everything. |
| 1551 | */ |
| 1552 | for (x = 0; x < cr; x += r) { |
| 1553 | for (y = 0; y < cr; y += c) { |
| 1554 | int xx, yy; |
| 1555 | memset(used, FALSE, cr); |
| 1556 | for (xx = x; xx < x+r; xx++) |
| 1557 | for (yy = 0; yy < y+c; yy++) |
| 1558 | if (grid[yy*cr+xx] > 0 && grid[yy*cr+xx] <= cr) |
| 1559 | used[grid[yy*cr+xx]-1] = TRUE; |
| 1560 | for (n = 0; n < cr; n++) |
| 1561 | if (!used[n]) { |
| 1562 | sfree(used); |
| 1563 | return FALSE; |
| 1564 | } |
| 1565 | } |
| 1566 | } |
| 1567 | |
| 1568 | sfree(used); |
| 1569 | return TRUE; |
| 1570 | } |
| 1571 | |
| 1572 | static int symmetries(game_params *params, int x, int y, int *output, int s) |
| 1573 | { |
| 1574 | int c = params->c, r = params->r, cr = c*r; |
| 1575 | int i = 0; |
| 1576 | |
| 1577 | #define ADD(x,y) (*output++ = (x), *output++ = (y), i++) |
| 1578 | |
| 1579 | ADD(x, y); |
| 1580 | |
| 1581 | switch (s) { |
| 1582 | case SYMM_NONE: |
| 1583 | break; /* just x,y is all we need */ |
| 1584 | case SYMM_ROT2: |
| 1585 | ADD(cr - 1 - x, cr - 1 - y); |
| 1586 | break; |
| 1587 | case SYMM_ROT4: |
| 1588 | ADD(cr - 1 - y, x); |
| 1589 | ADD(y, cr - 1 - x); |
| 1590 | ADD(cr - 1 - x, cr - 1 - y); |
| 1591 | break; |
| 1592 | case SYMM_REF2: |
| 1593 | ADD(cr - 1 - x, y); |
| 1594 | break; |
| 1595 | case SYMM_REF2D: |
| 1596 | ADD(y, x); |
| 1597 | break; |
| 1598 | case SYMM_REF4: |
| 1599 | ADD(cr - 1 - x, y); |
| 1600 | ADD(x, cr - 1 - y); |
| 1601 | ADD(cr - 1 - x, cr - 1 - y); |
| 1602 | break; |
| 1603 | case SYMM_REF4D: |
| 1604 | ADD(y, x); |
| 1605 | ADD(cr - 1 - x, cr - 1 - y); |
| 1606 | ADD(cr - 1 - y, cr - 1 - x); |
| 1607 | break; |
| 1608 | case SYMM_REF8: |
| 1609 | ADD(cr - 1 - x, y); |
| 1610 | ADD(x, cr - 1 - y); |
| 1611 | ADD(cr - 1 - x, cr - 1 - y); |
| 1612 | ADD(y, x); |
| 1613 | ADD(y, cr - 1 - x); |
| 1614 | ADD(cr - 1 - y, x); |
| 1615 | ADD(cr - 1 - y, cr - 1 - x); |
| 1616 | break; |
| 1617 | } |
| 1618 | |
| 1619 | #undef ADD |
| 1620 | |
| 1621 | return i; |
| 1622 | } |
| 1623 | |
| 1624 | static char *encode_solve_move(int cr, digit *grid) |
| 1625 | { |
| 1626 | int i, len; |
| 1627 | char *ret, *p, *sep; |
| 1628 | |
| 1629 | /* |
| 1630 | * It's surprisingly easy to work out _exactly_ how long this |
| 1631 | * string needs to be. To decimal-encode all the numbers from 1 |
| 1632 | * to n: |
| 1633 | * |
| 1634 | * - every number has a units digit; total is n. |
| 1635 | * - all numbers above 9 have a tens digit; total is max(n-9,0). |
| 1636 | * - all numbers above 99 have a hundreds digit; total is max(n-99,0). |
| 1637 | * - and so on. |
| 1638 | */ |
| 1639 | len = 0; |
| 1640 | for (i = 1; i <= cr; i *= 10) |
| 1641 | len += max(cr - i + 1, 0); |
| 1642 | len += cr; /* don't forget the commas */ |
| 1643 | len *= cr; /* there are cr rows of these */ |
| 1644 | |
| 1645 | /* |
| 1646 | * Now len is one bigger than the total size of the |
| 1647 | * comma-separated numbers (because we counted an |
| 1648 | * additional leading comma). We need to have a leading S |
| 1649 | * and a trailing NUL, so we're off by one in total. |
| 1650 | */ |
| 1651 | len++; |
| 1652 | |
| 1653 | ret = snewn(len, char); |
| 1654 | p = ret; |
| 1655 | *p++ = 'S'; |
| 1656 | sep = ""; |
| 1657 | for (i = 0; i < cr*cr; i++) { |
| 1658 | p += sprintf(p, "%s%d", sep, grid[i]); |
| 1659 | sep = ","; |
| 1660 | } |
| 1661 | *p++ = '\0'; |
| 1662 | assert(p - ret == len); |
| 1663 | |
| 1664 | return ret; |
| 1665 | } |
| 1666 | |
| 1667 | static char *new_game_desc(game_params *params, random_state *rs, |
| 1668 | char **aux, int interactive) |
| 1669 | { |
| 1670 | int c = params->c, r = params->r, cr = c*r; |
| 1671 | int area = cr*cr; |
| 1672 | digit *grid, *grid2; |
| 1673 | struct xy { int x, y; } *locs; |
| 1674 | int nlocs; |
| 1675 | char *desc; |
| 1676 | int coords[16], ncoords; |
| 1677 | int maxdiff; |
| 1678 | int x, y, i, j; |
| 1679 | |
| 1680 | /* |
| 1681 | * Adjust the maximum difficulty level to be consistent with |
| 1682 | * the puzzle size: all 2x2 puzzles appear to be Trivial |
| 1683 | * (DIFF_BLOCK) so we cannot hold out for even a Basic |
| 1684 | * (DIFF_SIMPLE) one. |
| 1685 | */ |
| 1686 | maxdiff = params->diff; |
| 1687 | if (c == 2 && r == 2) |
| 1688 | maxdiff = DIFF_BLOCK; |
| 1689 | |
| 1690 | grid = snewn(area, digit); |
| 1691 | locs = snewn(area, struct xy); |
| 1692 | grid2 = snewn(area, digit); |
| 1693 | |
| 1694 | /* |
| 1695 | * Loop until we get a grid of the required difficulty. This is |
| 1696 | * nasty, but it seems to be unpleasantly hard to generate |
| 1697 | * difficult grids otherwise. |
| 1698 | */ |
| 1699 | do { |
| 1700 | /* |
| 1701 | * Generate a random solved state. |
| 1702 | */ |
| 1703 | gridgen(c, r, grid, rs); |
| 1704 | assert(check_valid(c, r, grid)); |
| 1705 | |
| 1706 | /* |
| 1707 | * Save the solved grid in aux. |
| 1708 | */ |
| 1709 | { |
| 1710 | /* |
| 1711 | * We might already have written *aux the last time we |
| 1712 | * went round this loop, in which case we should free |
| 1713 | * the old aux before overwriting it with the new one. |
| 1714 | */ |
| 1715 | if (*aux) { |
| 1716 | sfree(*aux); |
| 1717 | } |
| 1718 | |
| 1719 | *aux = encode_solve_move(cr, grid); |
| 1720 | } |
| 1721 | |
| 1722 | /* |
| 1723 | * Now we have a solved grid, start removing things from it |
| 1724 | * while preserving solubility. |
| 1725 | */ |
| 1726 | |
| 1727 | /* |
| 1728 | * Find the set of equivalence classes of squares permitted |
| 1729 | * by the selected symmetry. We do this by enumerating all |
| 1730 | * the grid squares which have no symmetric companion |
| 1731 | * sorting lower than themselves. |
| 1732 | */ |
| 1733 | nlocs = 0; |
| 1734 | for (y = 0; y < cr; y++) |
| 1735 | for (x = 0; x < cr; x++) { |
| 1736 | int i = y*cr+x; |
| 1737 | int j; |
| 1738 | |
| 1739 | ncoords = symmetries(params, x, y, coords, params->symm); |
| 1740 | for (j = 0; j < ncoords; j++) |
| 1741 | if (coords[2*j+1]*cr+coords[2*j] < i) |
| 1742 | break; |
| 1743 | if (j == ncoords) { |
| 1744 | locs[nlocs].x = x; |
| 1745 | locs[nlocs].y = y; |
| 1746 | nlocs++; |
| 1747 | } |
| 1748 | } |
| 1749 | |
| 1750 | /* |
| 1751 | * Now shuffle that list. |
| 1752 | */ |
| 1753 | shuffle(locs, nlocs, sizeof(*locs), rs); |
| 1754 | |
| 1755 | /* |
| 1756 | * Now loop over the shuffled list and, for each element, |
| 1757 | * see whether removing that element (and its reflections) |
| 1758 | * from the grid will still leave the grid soluble. |
| 1759 | */ |
| 1760 | for (i = 0; i < nlocs; i++) { |
| 1761 | int ret; |
| 1762 | |
| 1763 | x = locs[i].x; |
| 1764 | y = locs[i].y; |
| 1765 | |
| 1766 | memcpy(grid2, grid, area); |
| 1767 | ncoords = symmetries(params, x, y, coords, params->symm); |
| 1768 | for (j = 0; j < ncoords; j++) |
| 1769 | grid2[coords[2*j+1]*cr+coords[2*j]] = 0; |
| 1770 | |
| 1771 | ret = solver(c, r, grid2, maxdiff); |
| 1772 | if (ret != DIFF_IMPOSSIBLE && ret != DIFF_AMBIGUOUS) { |
| 1773 | for (j = 0; j < ncoords; j++) |
| 1774 | grid[coords[2*j+1]*cr+coords[2*j]] = 0; |
| 1775 | } |
| 1776 | } |
| 1777 | |
| 1778 | memcpy(grid2, grid, area); |
| 1779 | } while (solver(c, r, grid2, maxdiff) < maxdiff); |
| 1780 | |
| 1781 | sfree(grid2); |
| 1782 | sfree(locs); |
| 1783 | |
| 1784 | /* |
| 1785 | * Now we have the grid as it will be presented to the user. |
| 1786 | * Encode it in a game desc. |
| 1787 | */ |
| 1788 | { |
| 1789 | char *p; |
| 1790 | int run, i; |
| 1791 | |
| 1792 | desc = snewn(5 * area, char); |
| 1793 | p = desc; |
| 1794 | run = 0; |
| 1795 | for (i = 0; i <= area; i++) { |
| 1796 | int n = (i < area ? grid[i] : -1); |
| 1797 | |
| 1798 | if (!n) |
| 1799 | run++; |
| 1800 | else { |
| 1801 | if (run) { |
| 1802 | while (run > 0) { |
| 1803 | int c = 'a' - 1 + run; |
| 1804 | if (run > 26) |
| 1805 | c = 'z'; |
| 1806 | *p++ = c; |
| 1807 | run -= c - ('a' - 1); |
| 1808 | } |
| 1809 | } else { |
| 1810 | /* |
| 1811 | * If there's a number in the very top left or |
| 1812 | * bottom right, there's no point putting an |
| 1813 | * unnecessary _ before or after it. |
| 1814 | */ |
| 1815 | if (p > desc && n > 0) |
| 1816 | *p++ = '_'; |
| 1817 | } |
| 1818 | if (n > 0) |
| 1819 | p += sprintf(p, "%d", n); |
| 1820 | run = 0; |
| 1821 | } |
| 1822 | } |
| 1823 | assert(p - desc < 5 * area); |
| 1824 | *p++ = '\0'; |
| 1825 | desc = sresize(desc, p - desc, char); |
| 1826 | } |
| 1827 | |
| 1828 | sfree(grid); |
| 1829 | |
| 1830 | return desc; |
| 1831 | } |
| 1832 | |
| 1833 | static char *validate_desc(game_params *params, char *desc) |
| 1834 | { |
| 1835 | int area = params->r * params->r * params->c * params->c; |
| 1836 | int squares = 0; |
| 1837 | |
| 1838 | while (*desc) { |
| 1839 | int n = *desc++; |
| 1840 | if (n >= 'a' && n <= 'z') { |
| 1841 | squares += n - 'a' + 1; |
| 1842 | } else if (n == '_') { |
| 1843 | /* do nothing */; |
| 1844 | } else if (n > '0' && n <= '9') { |
| 1845 | squares++; |
| 1846 | while (*desc >= '0' && *desc <= '9') |
| 1847 | desc++; |
| 1848 | } else |
| 1849 | return "Invalid character in game description"; |
| 1850 | } |
| 1851 | |
| 1852 | if (squares < area) |
| 1853 | return "Not enough data to fill grid"; |
| 1854 | |
| 1855 | if (squares > area) |
| 1856 | return "Too much data to fit in grid"; |
| 1857 | |
| 1858 | return NULL; |
| 1859 | } |
| 1860 | |
| 1861 | static game_state *new_game(midend_data *me, game_params *params, char *desc) |
| 1862 | { |
| 1863 | game_state *state = snew(game_state); |
| 1864 | int c = params->c, r = params->r, cr = c*r, area = cr * cr; |
| 1865 | int i; |
| 1866 | |
| 1867 | state->c = params->c; |
| 1868 | state->r = params->r; |
| 1869 | |
| 1870 | state->grid = snewn(area, digit); |
| 1871 | state->pencil = snewn(area * cr, unsigned char); |
| 1872 | memset(state->pencil, 0, area * cr); |
| 1873 | state->immutable = snewn(area, unsigned char); |
| 1874 | memset(state->immutable, FALSE, area); |
| 1875 | |
| 1876 | state->completed = state->cheated = FALSE; |
| 1877 | |
| 1878 | i = 0; |
| 1879 | while (*desc) { |
| 1880 | int n = *desc++; |
| 1881 | if (n >= 'a' && n <= 'z') { |
| 1882 | int run = n - 'a' + 1; |
| 1883 | assert(i + run <= area); |
| 1884 | while (run-- > 0) |
| 1885 | state->grid[i++] = 0; |
| 1886 | } else if (n == '_') { |
| 1887 | /* do nothing */; |
| 1888 | } else if (n > '0' && n <= '9') { |
| 1889 | assert(i < area); |
| 1890 | state->immutable[i] = TRUE; |
| 1891 | state->grid[i++] = atoi(desc-1); |
| 1892 | while (*desc >= '0' && *desc <= '9') |
| 1893 | desc++; |
| 1894 | } else { |
| 1895 | assert(!"We can't get here"); |
| 1896 | } |
| 1897 | } |
| 1898 | assert(i == area); |
| 1899 | |
| 1900 | return state; |
| 1901 | } |
| 1902 | |
| 1903 | static game_state *dup_game(game_state *state) |
| 1904 | { |
| 1905 | game_state *ret = snew(game_state); |
| 1906 | int c = state->c, r = state->r, cr = c*r, area = cr * cr; |
| 1907 | |
| 1908 | ret->c = state->c; |
| 1909 | ret->r = state->r; |
| 1910 | |
| 1911 | ret->grid = snewn(area, digit); |
| 1912 | memcpy(ret->grid, state->grid, area); |
| 1913 | |
| 1914 | ret->pencil = snewn(area * cr, unsigned char); |
| 1915 | memcpy(ret->pencil, state->pencil, area * cr); |
| 1916 | |
| 1917 | ret->immutable = snewn(area, unsigned char); |
| 1918 | memcpy(ret->immutable, state->immutable, area); |
| 1919 | |
| 1920 | ret->completed = state->completed; |
| 1921 | ret->cheated = state->cheated; |
| 1922 | |
| 1923 | return ret; |
| 1924 | } |
| 1925 | |
| 1926 | static void free_game(game_state *state) |
| 1927 | { |
| 1928 | sfree(state->immutable); |
| 1929 | sfree(state->pencil); |
| 1930 | sfree(state->grid); |
| 1931 | sfree(state); |
| 1932 | } |
| 1933 | |
| 1934 | static char *solve_game(game_state *state, game_state *currstate, |
| 1935 | char *ai, char **error) |
| 1936 | { |
| 1937 | int c = state->c, r = state->r, cr = c*r; |
| 1938 | char *ret; |
| 1939 | digit *grid; |
| 1940 | int solve_ret; |
| 1941 | |
| 1942 | /* |
| 1943 | * If we already have the solution in ai, save ourselves some |
| 1944 | * time. |
| 1945 | */ |
| 1946 | if (ai) |
| 1947 | return dupstr(ai); |
| 1948 | |
| 1949 | grid = snewn(cr*cr, digit); |
| 1950 | memcpy(grid, state->grid, cr*cr); |
| 1951 | solve_ret = solver(c, r, grid, DIFF_RECURSIVE); |
| 1952 | |
| 1953 | *error = NULL; |
| 1954 | |
| 1955 | if (solve_ret == DIFF_IMPOSSIBLE) |
| 1956 | *error = "No solution exists for this puzzle"; |
| 1957 | else if (solve_ret == DIFF_AMBIGUOUS) |
| 1958 | *error = "Multiple solutions exist for this puzzle"; |
| 1959 | |
| 1960 | if (*error) { |
| 1961 | sfree(grid); |
| 1962 | return NULL; |
| 1963 | } |
| 1964 | |
| 1965 | ret = encode_solve_move(cr, grid); |
| 1966 | |
| 1967 | sfree(grid); |
| 1968 | |
| 1969 | return ret; |
| 1970 | } |
| 1971 | |
| 1972 | static char *grid_text_format(int c, int r, digit *grid) |
| 1973 | { |
| 1974 | int cr = c*r; |
| 1975 | int x, y; |
| 1976 | int maxlen; |
| 1977 | char *ret, *p; |
| 1978 | |
| 1979 | /* |
| 1980 | * There are cr lines of digits, plus r-1 lines of block |
| 1981 | * separators. Each line contains cr digits, cr-1 separating |
| 1982 | * spaces, and c-1 two-character block separators. Thus, the |
| 1983 | * total length of a line is 2*cr+2*c-3 (not counting the |
| 1984 | * newline), and there are cr+r-1 of them. |
| 1985 | */ |
| 1986 | maxlen = (cr+r-1) * (2*cr+2*c-2); |
| 1987 | ret = snewn(maxlen+1, char); |
| 1988 | p = ret; |
| 1989 | |
| 1990 | for (y = 0; y < cr; y++) { |
| 1991 | for (x = 0; x < cr; x++) { |
| 1992 | int ch = grid[y * cr + x]; |
| 1993 | if (ch == 0) |
| 1994 | ch = ' '; |
| 1995 | else if (ch <= 9) |
| 1996 | ch = '0' + ch; |
| 1997 | else |
| 1998 | ch = 'a' + ch-10; |
| 1999 | *p++ = ch; |
| 2000 | if (x+1 < cr) { |
| 2001 | *p++ = ' '; |
| 2002 | if ((x+1) % r == 0) { |
| 2003 | *p++ = '|'; |
| 2004 | *p++ = ' '; |
| 2005 | } |
| 2006 | } |
| 2007 | } |
| 2008 | *p++ = '\n'; |
| 2009 | if (y+1 < cr && (y+1) % c == 0) { |
| 2010 | for (x = 0; x < cr; x++) { |
| 2011 | *p++ = '-'; |
| 2012 | if (x+1 < cr) { |
| 2013 | *p++ = '-'; |
| 2014 | if ((x+1) % r == 0) { |
| 2015 | *p++ = '+'; |
| 2016 | *p++ = '-'; |
| 2017 | } |
| 2018 | } |
| 2019 | } |
| 2020 | *p++ = '\n'; |
| 2021 | } |
| 2022 | } |
| 2023 | |
| 2024 | assert(p - ret == maxlen); |
| 2025 | *p = '\0'; |
| 2026 | return ret; |
| 2027 | } |
| 2028 | |
| 2029 | static char *game_text_format(game_state *state) |
| 2030 | { |
| 2031 | return grid_text_format(state->c, state->r, state->grid); |
| 2032 | } |
| 2033 | |
| 2034 | struct game_ui { |
| 2035 | /* |
| 2036 | * These are the coordinates of the currently highlighted |
| 2037 | * square on the grid, or -1,-1 if there isn't one. When there |
| 2038 | * is, pressing a valid number or letter key or Space will |
| 2039 | * enter that number or letter in the grid. |
| 2040 | */ |
| 2041 | int hx, hy; |
| 2042 | /* |
| 2043 | * This indicates whether the current highlight is a |
| 2044 | * pencil-mark one or a real one. |
| 2045 | */ |
| 2046 | int hpencil; |
| 2047 | }; |
| 2048 | |
| 2049 | static game_ui *new_ui(game_state *state) |
| 2050 | { |
| 2051 | game_ui *ui = snew(game_ui); |
| 2052 | |
| 2053 | ui->hx = ui->hy = -1; |
| 2054 | ui->hpencil = 0; |
| 2055 | |
| 2056 | return ui; |
| 2057 | } |
| 2058 | |
| 2059 | static void free_ui(game_ui *ui) |
| 2060 | { |
| 2061 | sfree(ui); |
| 2062 | } |
| 2063 | |
| 2064 | static char *encode_ui(game_ui *ui) |
| 2065 | { |
| 2066 | return NULL; |
| 2067 | } |
| 2068 | |
| 2069 | static void decode_ui(game_ui *ui, char *encoding) |
| 2070 | { |
| 2071 | } |
| 2072 | |
| 2073 | static void game_changed_state(game_ui *ui, game_state *oldstate, |
| 2074 | game_state *newstate) |
| 2075 | { |
| 2076 | int c = newstate->c, r = newstate->r, cr = c*r; |
| 2077 | /* |
| 2078 | * We prevent pencil-mode highlighting of a filled square. So |
| 2079 | * if the user has just filled in a square which we had a |
| 2080 | * pencil-mode highlight in (by Undo, or by Redo, or by Solve), |
| 2081 | * then we cancel the highlight. |
| 2082 | */ |
| 2083 | if (ui->hx >= 0 && ui->hy >= 0 && ui->hpencil && |
| 2084 | newstate->grid[ui->hy * cr + ui->hx] != 0) { |
| 2085 | ui->hx = ui->hy = -1; |
| 2086 | } |
| 2087 | } |
| 2088 | |
| 2089 | struct game_drawstate { |
| 2090 | int started; |
| 2091 | int c, r, cr; |
| 2092 | int tilesize; |
| 2093 | digit *grid; |
| 2094 | unsigned char *pencil; |
| 2095 | unsigned char *hl; |
| 2096 | /* This is scratch space used within a single call to game_redraw. */ |
| 2097 | int *entered_items; |
| 2098 | }; |
| 2099 | |
| 2100 | static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds, |
| 2101 | int x, int y, int button) |
| 2102 | { |
| 2103 | int c = state->c, r = state->r, cr = c*r; |
| 2104 | int tx, ty; |
| 2105 | char buf[80]; |
| 2106 | |
| 2107 | button &= ~MOD_MASK; |
| 2108 | |
| 2109 | tx = (x + TILE_SIZE - BORDER) / TILE_SIZE - 1; |
| 2110 | ty = (y + TILE_SIZE - BORDER) / TILE_SIZE - 1; |
| 2111 | |
| 2112 | if (tx >= 0 && tx < cr && ty >= 0 && ty < cr) { |
| 2113 | if (button == LEFT_BUTTON) { |
| 2114 | if (state->immutable[ty*cr+tx]) { |
| 2115 | ui->hx = ui->hy = -1; |
| 2116 | } else if (tx == ui->hx && ty == ui->hy && ui->hpencil == 0) { |
| 2117 | ui->hx = ui->hy = -1; |
| 2118 | } else { |
| 2119 | ui->hx = tx; |
| 2120 | ui->hy = ty; |
| 2121 | ui->hpencil = 0; |
| 2122 | } |
| 2123 | return ""; /* UI activity occurred */ |
| 2124 | } |
| 2125 | if (button == RIGHT_BUTTON) { |
| 2126 | /* |
| 2127 | * Pencil-mode highlighting for non filled squares. |
| 2128 | */ |
| 2129 | if (state->grid[ty*cr+tx] == 0) { |
| 2130 | if (tx == ui->hx && ty == ui->hy && ui->hpencil) { |
| 2131 | ui->hx = ui->hy = -1; |
| 2132 | } else { |
| 2133 | ui->hpencil = 1; |
| 2134 | ui->hx = tx; |
| 2135 | ui->hy = ty; |
| 2136 | } |
| 2137 | } else { |
| 2138 | ui->hx = ui->hy = -1; |
| 2139 | } |
| 2140 | return ""; /* UI activity occurred */ |
| 2141 | } |
| 2142 | } |
| 2143 | |
| 2144 | if (ui->hx != -1 && ui->hy != -1 && |
| 2145 | ((button >= '1' && button <= '9' && button - '0' <= cr) || |
| 2146 | (button >= 'a' && button <= 'z' && button - 'a' + 10 <= cr) || |
| 2147 | (button >= 'A' && button <= 'Z' && button - 'A' + 10 <= cr) || |
| 2148 | button == ' ')) { |
| 2149 | int n = button - '0'; |
| 2150 | if (button >= 'A' && button <= 'Z') |
| 2151 | n = button - 'A' + 10; |
| 2152 | if (button >= 'a' && button <= 'z') |
| 2153 | n = button - 'a' + 10; |
| 2154 | if (button == ' ') |
| 2155 | n = 0; |
| 2156 | |
| 2157 | /* |
| 2158 | * Can't overwrite this square. In principle this shouldn't |
| 2159 | * happen anyway because we should never have even been |
| 2160 | * able to highlight the square, but it never hurts to be |
| 2161 | * careful. |
| 2162 | */ |
| 2163 | if (state->immutable[ui->hy*cr+ui->hx]) |
| 2164 | return NULL; |
| 2165 | |
| 2166 | /* |
| 2167 | * Can't make pencil marks in a filled square. In principle |
| 2168 | * this shouldn't happen anyway because we should never |
| 2169 | * have even been able to pencil-highlight the square, but |
| 2170 | * it never hurts to be careful. |
| 2171 | */ |
| 2172 | if (ui->hpencil && state->grid[ui->hy*cr+ui->hx]) |
| 2173 | return NULL; |
| 2174 | |
| 2175 | sprintf(buf, "%c%d,%d,%d", |
| 2176 | (char)(ui->hpencil && n > 0 ? 'P' : 'R'), ui->hx, ui->hy, n); |
| 2177 | |
| 2178 | ui->hx = ui->hy = -1; |
| 2179 | |
| 2180 | return dupstr(buf); |
| 2181 | } |
| 2182 | |
| 2183 | return NULL; |
| 2184 | } |
| 2185 | |
| 2186 | static game_state *execute_move(game_state *from, char *move) |
| 2187 | { |
| 2188 | int c = from->c, r = from->r, cr = c*r; |
| 2189 | game_state *ret; |
| 2190 | int x, y, n; |
| 2191 | |
| 2192 | if (move[0] == 'S') { |
| 2193 | char *p; |
| 2194 | |
| 2195 | ret = dup_game(from); |
| 2196 | ret->completed = ret->cheated = TRUE; |
| 2197 | |
| 2198 | p = move+1; |
| 2199 | for (n = 0; n < cr*cr; n++) { |
| 2200 | ret->grid[n] = atoi(p); |
| 2201 | |
| 2202 | if (!*p || ret->grid[n] < 1 || ret->grid[n] > cr) { |
| 2203 | free_game(ret); |
| 2204 | return NULL; |
| 2205 | } |
| 2206 | |
| 2207 | while (*p && isdigit((unsigned char)*p)) p++; |
| 2208 | if (*p == ',') p++; |
| 2209 | } |
| 2210 | |
| 2211 | return ret; |
| 2212 | } else if ((move[0] == 'P' || move[0] == 'R') && |
| 2213 | sscanf(move+1, "%d,%d,%d", &x, &y, &n) == 3 && |
| 2214 | x >= 0 && x < cr && y >= 0 && y < cr && n >= 0 && n <= cr) { |
| 2215 | |
| 2216 | ret = dup_game(from); |
| 2217 | if (move[0] == 'P' && n > 0) { |
| 2218 | int index = (y*cr+x) * cr + (n-1); |
| 2219 | ret->pencil[index] = !ret->pencil[index]; |
| 2220 | } else { |
| 2221 | ret->grid[y*cr+x] = n; |
| 2222 | memset(ret->pencil + (y*cr+x)*cr, 0, cr); |
| 2223 | |
| 2224 | /* |
| 2225 | * We've made a real change to the grid. Check to see |
| 2226 | * if the game has been completed. |
| 2227 | */ |
| 2228 | if (!ret->completed && check_valid(c, r, ret->grid)) { |
| 2229 | ret->completed = TRUE; |
| 2230 | } |
| 2231 | } |
| 2232 | return ret; |
| 2233 | } else |
| 2234 | return NULL; /* couldn't parse move string */ |
| 2235 | } |
| 2236 | |
| 2237 | /* ---------------------------------------------------------------------- |
| 2238 | * Drawing routines. |
| 2239 | */ |
| 2240 | |
| 2241 | #define SIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1) |
| 2242 | #define GETTILESIZE(cr, w) ( (double)(w-1) / (double)(cr+1) ) |
| 2243 | |
| 2244 | static void game_compute_size(game_params *params, int tilesize, |
| 2245 | int *x, int *y) |
| 2246 | { |
| 2247 | /* Ick: fake up `ds->tilesize' for macro expansion purposes */ |
| 2248 | struct { int tilesize; } ads, *ds = &ads; |
| 2249 | ads.tilesize = tilesize; |
| 2250 | |
| 2251 | *x = SIZE(params->c * params->r); |
| 2252 | *y = SIZE(params->c * params->r); |
| 2253 | } |
| 2254 | |
| 2255 | static void game_set_size(game_drawstate *ds, game_params *params, |
| 2256 | int tilesize) |
| 2257 | { |
| 2258 | ds->tilesize = tilesize; |
| 2259 | } |
| 2260 | |
| 2261 | static float *game_colours(frontend *fe, game_state *state, int *ncolours) |
| 2262 | { |
| 2263 | float *ret = snewn(3 * NCOLOURS, float); |
| 2264 | |
| 2265 | frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]); |
| 2266 | |
| 2267 | ret[COL_GRID * 3 + 0] = 0.0F; |
| 2268 | ret[COL_GRID * 3 + 1] = 0.0F; |
| 2269 | ret[COL_GRID * 3 + 2] = 0.0F; |
| 2270 | |
| 2271 | ret[COL_CLUE * 3 + 0] = 0.0F; |
| 2272 | ret[COL_CLUE * 3 + 1] = 0.0F; |
| 2273 | ret[COL_CLUE * 3 + 2] = 0.0F; |
| 2274 | |
| 2275 | ret[COL_USER * 3 + 0] = 0.0F; |
| 2276 | ret[COL_USER * 3 + 1] = 0.6F * ret[COL_BACKGROUND * 3 + 1]; |
| 2277 | ret[COL_USER * 3 + 2] = 0.0F; |
| 2278 | |
| 2279 | ret[COL_HIGHLIGHT * 3 + 0] = 0.85F * ret[COL_BACKGROUND * 3 + 0]; |
| 2280 | ret[COL_HIGHLIGHT * 3 + 1] = 0.85F * ret[COL_BACKGROUND * 3 + 1]; |
| 2281 | ret[COL_HIGHLIGHT * 3 + 2] = 0.85F * ret[COL_BACKGROUND * 3 + 2]; |
| 2282 | |
| 2283 | ret[COL_ERROR * 3 + 0] = 1.0F; |
| 2284 | ret[COL_ERROR * 3 + 1] = 0.0F; |
| 2285 | ret[COL_ERROR * 3 + 2] = 0.0F; |
| 2286 | |
| 2287 | ret[COL_PENCIL * 3 + 0] = 0.5F * ret[COL_BACKGROUND * 3 + 0]; |
| 2288 | ret[COL_PENCIL * 3 + 1] = 0.5F * ret[COL_BACKGROUND * 3 + 1]; |
| 2289 | ret[COL_PENCIL * 3 + 2] = ret[COL_BACKGROUND * 3 + 2]; |
| 2290 | |
| 2291 | *ncolours = NCOLOURS; |
| 2292 | return ret; |
| 2293 | } |
| 2294 | |
| 2295 | static game_drawstate *game_new_drawstate(game_state *state) |
| 2296 | { |
| 2297 | struct game_drawstate *ds = snew(struct game_drawstate); |
| 2298 | int c = state->c, r = state->r, cr = c*r; |
| 2299 | |
| 2300 | ds->started = FALSE; |
| 2301 | ds->c = c; |
| 2302 | ds->r = r; |
| 2303 | ds->cr = cr; |
| 2304 | ds->grid = snewn(cr*cr, digit); |
| 2305 | memset(ds->grid, 0, cr*cr); |
| 2306 | ds->pencil = snewn(cr*cr*cr, digit); |
| 2307 | memset(ds->pencil, 0, cr*cr*cr); |
| 2308 | ds->hl = snewn(cr*cr, unsigned char); |
| 2309 | memset(ds->hl, 0, cr*cr); |
| 2310 | ds->entered_items = snewn(cr*cr, int); |
| 2311 | ds->tilesize = 0; /* not decided yet */ |
| 2312 | return ds; |
| 2313 | } |
| 2314 | |
| 2315 | static void game_free_drawstate(game_drawstate *ds) |
| 2316 | { |
| 2317 | sfree(ds->hl); |
| 2318 | sfree(ds->pencil); |
| 2319 | sfree(ds->grid); |
| 2320 | sfree(ds->entered_items); |
| 2321 | sfree(ds); |
| 2322 | } |
| 2323 | |
| 2324 | static void draw_number(frontend *fe, game_drawstate *ds, game_state *state, |
| 2325 | int x, int y, int hl) |
| 2326 | { |
| 2327 | int c = state->c, r = state->r, cr = c*r; |
| 2328 | int tx, ty; |
| 2329 | int cx, cy, cw, ch; |
| 2330 | char str[2]; |
| 2331 | |
| 2332 | if (ds->grid[y*cr+x] == state->grid[y*cr+x] && |
| 2333 | ds->hl[y*cr+x] == hl && |
| 2334 | !memcmp(ds->pencil+(y*cr+x)*cr, state->pencil+(y*cr+x)*cr, cr)) |
| 2335 | return; /* no change required */ |
| 2336 | |
| 2337 | tx = BORDER + x * TILE_SIZE + 2; |
| 2338 | ty = BORDER + y * TILE_SIZE + 2; |
| 2339 | |
| 2340 | cx = tx; |
| 2341 | cy = ty; |
| 2342 | cw = TILE_SIZE-3; |
| 2343 | ch = TILE_SIZE-3; |
| 2344 | |
| 2345 | if (x % r) |
| 2346 | cx--, cw++; |
| 2347 | if ((x+1) % r) |
| 2348 | cw++; |
| 2349 | if (y % c) |
| 2350 | cy--, ch++; |
| 2351 | if ((y+1) % c) |
| 2352 | ch++; |
| 2353 | |
| 2354 | clip(fe, cx, cy, cw, ch); |
| 2355 | |
| 2356 | /* background needs erasing */ |
| 2357 | draw_rect(fe, cx, cy, cw, ch, (hl & 15) == 1 ? COL_HIGHLIGHT : COL_BACKGROUND); |
| 2358 | |
| 2359 | /* pencil-mode highlight */ |
| 2360 | if ((hl & 15) == 2) { |
| 2361 | int coords[6]; |
| 2362 | coords[0] = cx; |
| 2363 | coords[1] = cy; |
| 2364 | coords[2] = cx+cw/2; |
| 2365 | coords[3] = cy; |
| 2366 | coords[4] = cx; |
| 2367 | coords[5] = cy+ch/2; |
| 2368 | draw_polygon(fe, coords, 3, COL_HIGHLIGHT, COL_HIGHLIGHT); |
| 2369 | } |
| 2370 | |
| 2371 | /* new number needs drawing? */ |
| 2372 | if (state->grid[y*cr+x]) { |
| 2373 | str[1] = '\0'; |
| 2374 | str[0] = state->grid[y*cr+x] + '0'; |
| 2375 | if (str[0] > '9') |
| 2376 | str[0] += 'a' - ('9'+1); |
| 2377 | draw_text(fe, tx + TILE_SIZE/2, ty + TILE_SIZE/2, |
| 2378 | FONT_VARIABLE, TILE_SIZE/2, ALIGN_VCENTRE | ALIGN_HCENTRE, |
| 2379 | state->immutable[y*cr+x] ? COL_CLUE : (hl & 16) ? COL_ERROR : COL_USER, str); |
| 2380 | } else { |
| 2381 | int i, j, npencil; |
| 2382 | int pw, ph, pmax, fontsize; |
| 2383 | |
| 2384 | /* count the pencil marks required */ |
| 2385 | for (i = npencil = 0; i < cr; i++) |
| 2386 | if (state->pencil[(y*cr+x)*cr+i]) |
| 2387 | npencil++; |
| 2388 | |
| 2389 | /* |
| 2390 | * It's not sensible to arrange pencil marks in the same |
| 2391 | * layout as the squares within a block, because this leads |
| 2392 | * to the font being too small. Instead, we arrange pencil |
| 2393 | * marks in the nearest thing we can to a square layout, |
| 2394 | * and we adjust the square layout depending on the number |
| 2395 | * of pencil marks in the square. |
| 2396 | */ |
| 2397 | for (pw = 1; pw * pw < npencil; pw++); |
| 2398 | if (pw < 3) pw = 3; /* otherwise it just looks _silly_ */ |
| 2399 | ph = (npencil + pw - 1) / pw; |
| 2400 | if (ph < 2) ph = 2; /* likewise */ |
| 2401 | pmax = max(pw, ph); |
| 2402 | fontsize = TILE_SIZE/(pmax*(11-pmax)/8); |
| 2403 | |
| 2404 | for (i = j = 0; i < cr; i++) |
| 2405 | if (state->pencil[(y*cr+x)*cr+i]) { |
| 2406 | int dx = j % pw, dy = j / pw; |
| 2407 | |
| 2408 | str[1] = '\0'; |
| 2409 | str[0] = i + '1'; |
| 2410 | if (str[0] > '9') |
| 2411 | str[0] += 'a' - ('9'+1); |
| 2412 | draw_text(fe, tx + (4*dx+3) * TILE_SIZE / (4*pw+2), |
| 2413 | ty + (4*dy+3) * TILE_SIZE / (4*ph+2), |
| 2414 | FONT_VARIABLE, fontsize, |
| 2415 | ALIGN_VCENTRE | ALIGN_HCENTRE, COL_PENCIL, str); |
| 2416 | j++; |
| 2417 | } |
| 2418 | } |
| 2419 | |
| 2420 | unclip(fe); |
| 2421 | |
| 2422 | draw_update(fe, cx, cy, cw, ch); |
| 2423 | |
| 2424 | ds->grid[y*cr+x] = state->grid[y*cr+x]; |
| 2425 | memcpy(ds->pencil+(y*cr+x)*cr, state->pencil+(y*cr+x)*cr, cr); |
| 2426 | ds->hl[y*cr+x] = hl; |
| 2427 | } |
| 2428 | |
| 2429 | static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate, |
| 2430 | game_state *state, int dir, game_ui *ui, |
| 2431 | float animtime, float flashtime) |
| 2432 | { |
| 2433 | int c = state->c, r = state->r, cr = c*r; |
| 2434 | int x, y; |
| 2435 | |
| 2436 | if (!ds->started) { |
| 2437 | /* |
| 2438 | * The initial contents of the window are not guaranteed |
| 2439 | * and can vary with front ends. To be on the safe side, |
| 2440 | * all games should start by drawing a big |
| 2441 | * background-colour rectangle covering the whole window. |
| 2442 | */ |
| 2443 | draw_rect(fe, 0, 0, SIZE(cr), SIZE(cr), COL_BACKGROUND); |
| 2444 | |
| 2445 | /* |
| 2446 | * Draw the grid. |
| 2447 | */ |
| 2448 | for (x = 0; x <= cr; x++) { |
| 2449 | int thick = (x % r ? 0 : 1); |
| 2450 | draw_rect(fe, BORDER + x*TILE_SIZE - thick, BORDER-1, |
| 2451 | 1+2*thick, cr*TILE_SIZE+3, COL_GRID); |
| 2452 | } |
| 2453 | for (y = 0; y <= cr; y++) { |
| 2454 | int thick = (y % c ? 0 : 1); |
| 2455 | draw_rect(fe, BORDER-1, BORDER + y*TILE_SIZE - thick, |
| 2456 | cr*TILE_SIZE+3, 1+2*thick, COL_GRID); |
| 2457 | } |
| 2458 | } |
| 2459 | |
| 2460 | /* |
| 2461 | * This array is used to keep track of rows, columns and boxes |
| 2462 | * which contain a number more than once. |
| 2463 | */ |
| 2464 | for (x = 0; x < cr * cr; x++) |
| 2465 | ds->entered_items[x] = 0; |
| 2466 | for (x = 0; x < cr; x++) |
| 2467 | for (y = 0; y < cr; y++) { |
| 2468 | digit d = state->grid[y*cr+x]; |
| 2469 | if (d) { |
| 2470 | int box = (x/r)+(y/c)*c; |
| 2471 | ds->entered_items[x*cr+d-1] |= ((ds->entered_items[x*cr+d-1] & 1) << 1) | 1; |
| 2472 | ds->entered_items[y*cr+d-1] |= ((ds->entered_items[y*cr+d-1] & 4) << 1) | 4; |
| 2473 | ds->entered_items[box*cr+d-1] |= ((ds->entered_items[box*cr+d-1] & 16) << 1) | 16; |
| 2474 | } |
| 2475 | } |
| 2476 | |
| 2477 | /* |
| 2478 | * Draw any numbers which need redrawing. |
| 2479 | */ |
| 2480 | for (x = 0; x < cr; x++) { |
| 2481 | for (y = 0; y < cr; y++) { |
| 2482 | int highlight = 0; |
| 2483 | digit d = state->grid[y*cr+x]; |
| 2484 | |
| 2485 | if (flashtime > 0 && |
| 2486 | (flashtime <= FLASH_TIME/3 || |
| 2487 | flashtime >= FLASH_TIME*2/3)) |
| 2488 | highlight = 1; |
| 2489 | |
| 2490 | /* Highlight active input areas. */ |
| 2491 | if (x == ui->hx && y == ui->hy) |
| 2492 | highlight = ui->hpencil ? 2 : 1; |
| 2493 | |
| 2494 | /* Mark obvious errors (ie, numbers which occur more than once |
| 2495 | * in a single row, column, or box). */ |
| 2496 | if (d && ((ds->entered_items[x*cr+d-1] & 2) || |
| 2497 | (ds->entered_items[y*cr+d-1] & 8) || |
| 2498 | (ds->entered_items[((x/r)+(y/c)*c)*cr+d-1] & 32))) |
| 2499 | highlight |= 16; |
| 2500 | |
| 2501 | draw_number(fe, ds, state, x, y, highlight); |
| 2502 | } |
| 2503 | } |
| 2504 | |
| 2505 | /* |
| 2506 | * Update the _entire_ grid if necessary. |
| 2507 | */ |
| 2508 | if (!ds->started) { |
| 2509 | draw_update(fe, 0, 0, SIZE(cr), SIZE(cr)); |
| 2510 | ds->started = TRUE; |
| 2511 | } |
| 2512 | } |
| 2513 | |
| 2514 | static float game_anim_length(game_state *oldstate, game_state *newstate, |
| 2515 | int dir, game_ui *ui) |
| 2516 | { |
| 2517 | return 0.0F; |
| 2518 | } |
| 2519 | |
| 2520 | static float game_flash_length(game_state *oldstate, game_state *newstate, |
| 2521 | int dir, game_ui *ui) |
| 2522 | { |
| 2523 | if (!oldstate->completed && newstate->completed && |
| 2524 | !oldstate->cheated && !newstate->cheated) |
| 2525 | return FLASH_TIME; |
| 2526 | return 0.0F; |
| 2527 | } |
| 2528 | |
| 2529 | static int game_wants_statusbar(void) |
| 2530 | { |
| 2531 | return FALSE; |
| 2532 | } |
| 2533 | |
| 2534 | static int game_timing_state(game_state *state, game_ui *ui) |
| 2535 | { |
| 2536 | return TRUE; |
| 2537 | } |
| 2538 | |
| 2539 | #ifdef COMBINED |
| 2540 | #define thegame solo |
| 2541 | #endif |
| 2542 | |
| 2543 | const struct game thegame = { |
| 2544 | "Solo", "games.solo", |
| 2545 | default_params, |
| 2546 | game_fetch_preset, |
| 2547 | decode_params, |
| 2548 | encode_params, |
| 2549 | free_params, |
| 2550 | dup_params, |
| 2551 | TRUE, game_configure, custom_params, |
| 2552 | validate_params, |
| 2553 | new_game_desc, |
| 2554 | validate_desc, |
| 2555 | new_game, |
| 2556 | dup_game, |
| 2557 | free_game, |
| 2558 | TRUE, solve_game, |
| 2559 | TRUE, game_text_format, |
| 2560 | new_ui, |
| 2561 | free_ui, |
| 2562 | encode_ui, |
| 2563 | decode_ui, |
| 2564 | game_changed_state, |
| 2565 | interpret_move, |
| 2566 | execute_move, |
| 2567 | PREFERRED_TILE_SIZE, game_compute_size, game_set_size, |
| 2568 | game_colours, |
| 2569 | game_new_drawstate, |
| 2570 | game_free_drawstate, |
| 2571 | game_redraw, |
| 2572 | game_anim_length, |
| 2573 | game_flash_length, |
| 2574 | game_wants_statusbar, |
| 2575 | FALSE, game_timing_state, |
| 2576 | 0, /* mouse_priorities */ |
| 2577 | }; |
| 2578 | |
| 2579 | #ifdef STANDALONE_SOLVER |
| 2580 | |
| 2581 | /* |
| 2582 | * gcc -DSTANDALONE_SOLVER -o solosolver solo.c malloc.c |
| 2583 | */ |
| 2584 | |
| 2585 | void frontend_default_colour(frontend *fe, float *output) {} |
| 2586 | void draw_text(frontend *fe, int x, int y, int fonttype, int fontsize, |
| 2587 | int align, int colour, char *text) {} |
| 2588 | void draw_rect(frontend *fe, int x, int y, int w, int h, int colour) {} |
| 2589 | void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour) {} |
| 2590 | void draw_polygon(frontend *fe, int *coords, int npoints, |
| 2591 | int fillcolour, int outlinecolour) {} |
| 2592 | void clip(frontend *fe, int x, int y, int w, int h) {} |
| 2593 | void unclip(frontend *fe) {} |
| 2594 | void start_draw(frontend *fe) {} |
| 2595 | void draw_update(frontend *fe, int x, int y, int w, int h) {} |
| 2596 | void end_draw(frontend *fe) {} |
| 2597 | unsigned long random_bits(random_state *state, int bits) |
| 2598 | { assert(!"Shouldn't get randomness"); return 0; } |
| 2599 | unsigned long random_upto(random_state *state, unsigned long limit) |
| 2600 | { assert(!"Shouldn't get randomness"); return 0; } |
| 2601 | void shuffle(void *array, int nelts, int eltsize, random_state *rs) |
| 2602 | { assert(!"Shouldn't get randomness"); } |
| 2603 | |
| 2604 | void fatal(char *fmt, ...) |
| 2605 | { |
| 2606 | va_list ap; |
| 2607 | |
| 2608 | fprintf(stderr, "fatal error: "); |
| 2609 | |
| 2610 | va_start(ap, fmt); |
| 2611 | vfprintf(stderr, fmt, ap); |
| 2612 | va_end(ap); |
| 2613 | |
| 2614 | fprintf(stderr, "\n"); |
| 2615 | exit(1); |
| 2616 | } |
| 2617 | |
| 2618 | int main(int argc, char **argv) |
| 2619 | { |
| 2620 | game_params *p; |
| 2621 | game_state *s; |
| 2622 | char *id = NULL, *desc, *err; |
| 2623 | int grade = FALSE; |
| 2624 | int ret; |
| 2625 | |
| 2626 | while (--argc > 0) { |
| 2627 | char *p = *++argv; |
| 2628 | if (!strcmp(p, "-v")) { |
| 2629 | solver_show_working = TRUE; |
| 2630 | } else if (!strcmp(p, "-g")) { |
| 2631 | grade = TRUE; |
| 2632 | } else if (*p == '-') { |
| 2633 | fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p); |
| 2634 | return 1; |
| 2635 | } else { |
| 2636 | id = p; |
| 2637 | } |
| 2638 | } |
| 2639 | |
| 2640 | if (!id) { |
| 2641 | fprintf(stderr, "usage: %s [-g | -v] <game_id>\n", argv[0]); |
| 2642 | return 1; |
| 2643 | } |
| 2644 | |
| 2645 | desc = strchr(id, ':'); |
| 2646 | if (!desc) { |
| 2647 | fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]); |
| 2648 | return 1; |
| 2649 | } |
| 2650 | *desc++ = '\0'; |
| 2651 | |
| 2652 | p = default_params(); |
| 2653 | decode_params(p, id); |
| 2654 | err = validate_desc(p, desc); |
| 2655 | if (err) { |
| 2656 | fprintf(stderr, "%s: %s\n", argv[0], err); |
| 2657 | return 1; |
| 2658 | } |
| 2659 | s = new_game(NULL, p, desc); |
| 2660 | |
| 2661 | ret = solver(p->c, p->r, s->grid, DIFF_RECURSIVE); |
| 2662 | if (grade) { |
| 2663 | printf("Difficulty rating: %s\n", |
| 2664 | ret==DIFF_BLOCK ? "Trivial (blockwise positional elimination only)": |
| 2665 | ret==DIFF_SIMPLE ? "Basic (row/column/number elimination required)": |
| 2666 | ret==DIFF_INTERSECT ? "Intermediate (intersectional analysis required)": |
| 2667 | ret==DIFF_SET ? "Advanced (set elimination required)": |
| 2668 | ret==DIFF_RECURSIVE ? "Unreasonable (guesswork and backtracking required)": |
| 2669 | ret==DIFF_AMBIGUOUS ? "Ambiguous (multiple solutions exist)": |
| 2670 | ret==DIFF_IMPOSSIBLE ? "Impossible (no solution exists)": |
| 2671 | "INTERNAL ERROR: unrecognised difficulty code"); |
| 2672 | } else { |
| 2673 | printf("%s\n", grid_text_format(p->c, p->r, s->grid)); |
| 2674 | } |
| 2675 | |
| 2676 | return 0; |
| 2677 | } |
| 2678 | |
| 2679 | #endif |