X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/puzzles/blobdiff_plain/e3f21163e0737b17412f5bd8c184b26715c396fa..cccb7f09e28f348e9273467cc8e410ad13283165:/solo.c diff --git a/solo.c b/solo.c index 3272a56..a2f40eb 100644 --- a/solo.c +++ b/solo.c @@ -91,13 +91,11 @@ #ifdef STANDALONE_SOLVER #include -int solver_show_working; +int solver_show_working, solver_recurse_depth; #endif #include "puzzles.h" -#define max(x,y) ((x)>(y)?(x):(y)) - /* * To save space, I store digits internally as unsigned char. This * imposes a hard limit of 255 on the order of the puzzle. Since @@ -109,15 +107,17 @@ int solver_show_working; typedef unsigned char digit; #define ORDER_MAX 255 -#define TILE_SIZE 32 -#define BORDER 18 +#define PREFERRED_TILE_SIZE 32 +#define TILE_SIZE (ds->tilesize) +#define BORDER (TILE_SIZE / 2) #define FLASH_TIME 0.4F -enum { SYMM_NONE, SYMM_ROT2, SYMM_ROT4, SYMM_REF4 }; +enum { SYMM_NONE, SYMM_ROT2, SYMM_ROT4, SYMM_REF2, SYMM_REF2D, SYMM_REF4, + SYMM_REF4D, SYMM_REF8 }; -enum { DIFF_BLOCK, DIFF_SIMPLE, DIFF_INTERSECT, - DIFF_SET, DIFF_RECURSIVE, DIFF_AMBIGUOUS, DIFF_IMPOSSIBLE }; +enum { DIFF_BLOCK, DIFF_SIMPLE, DIFF_INTERSECT, DIFF_SET, DIFF_EXTREME, + DIFF_RECURSIVE, DIFF_AMBIGUOUS, DIFF_IMPOSSIBLE }; enum { COL_BACKGROUND, @@ -125,6 +125,7 @@ enum { COL_CLUE, COL_USER, COL_HIGHLIGHT, + COL_ERROR, COL_PENCIL, NCOLOURS }; @@ -176,9 +177,12 @@ static int game_fetch_preset(int i, char **name, game_params **params) { "3x3 Basic", { 3, 3, SYMM_ROT2, DIFF_SIMPLE } }, { "3x3 Intermediate", { 3, 3, SYMM_ROT2, DIFF_INTERSECT } }, { "3x3 Advanced", { 3, 3, SYMM_ROT2, DIFF_SET } }, + { "3x3 Extreme", { 3, 3, SYMM_ROT2, DIFF_EXTREME } }, { "3x3 Unreasonable", { 3, 3, SYMM_ROT2, DIFF_RECURSIVE } }, +#ifndef SLOW_SYSTEM { "3x4 Basic", { 3, 4, SYMM_ROT2, DIFF_SIMPLE } }, { "4x4 Basic", { 4, 4, SYMM_ROT2, DIFF_SIMPLE } }, +#endif }; if (i < 0 || i >= lenof(presets)) @@ -201,12 +205,22 @@ static void decode_params(game_params *ret, char const *string) } while (*string) { if (*string == 'r' || *string == 'm' || *string == 'a') { - int sn, sc; + int sn, sc, sd; sc = *string++; + if (*string == 'd') { + sd = TRUE; + string++; + } else { + sd = FALSE; + } sn = atoi(string); while (*string && isdigit((unsigned char)*string)) string++; + if (sc == 'm' && sn == 8) + ret->symm = SYMM_REF8; if (sc == 'm' && sn == 4) - ret->symm = SYMM_REF4; + ret->symm = sd ? SYMM_REF4D : SYMM_REF4; + if (sc == 'm' && sn == 2) + ret->symm = sd ? SYMM_REF2D : SYMM_REF2; if (sc == 'r' && sn == 4) ret->symm = SYMM_ROT4; if (sc == 'r' && sn == 2) @@ -223,6 +237,8 @@ static void decode_params(game_params *ret, char const *string) string++, ret->diff = DIFF_INTERSECT; else if (*string == 'a') /* advanced */ string++, ret->diff = DIFF_SET; + else if (*string == 'e') /* extreme */ + string++, ret->diff = DIFF_EXTREME; else if (*string == 'u') /* unreasonable */ string++, ret->diff = DIFF_RECURSIVE; } else @@ -237,7 +253,11 @@ static char *encode_params(game_params *params, int full) sprintf(str, "%dx%d", params->c, params->r); if (full) { switch (params->symm) { + case SYMM_REF8: strcat(str, "m8"); break; case SYMM_REF4: strcat(str, "m4"); break; + case SYMM_REF4D: strcat(str, "md4"); break; + case SYMM_REF2: strcat(str, "m2"); break; + case SYMM_REF2D: strcat(str, "md2"); break; case SYMM_ROT4: strcat(str, "r4"); break; /* case SYMM_ROT2: strcat(str, "r2"); break; [default] */ case SYMM_NONE: strcat(str, "a"); break; @@ -247,6 +267,7 @@ static char *encode_params(game_params *params, int full) case DIFF_SIMPLE: strcat(str, "db"); break; case DIFF_INTERSECT: strcat(str, "di"); break; case DIFF_SET: strcat(str, "da"); break; + case DIFF_EXTREME: strcat(str, "de"); break; case DIFF_RECURSIVE: strcat(str, "du"); break; } } @@ -274,12 +295,14 @@ static config_item *game_configure(game_params *params) ret[2].name = "Symmetry"; ret[2].type = C_CHOICES; - ret[2].sval = ":None:2-way rotation:4-way rotation:4-way mirror"; + ret[2].sval = ":None:2-way rotation:4-way rotation:2-way mirror:" + "2-way diagonal mirror:4-way mirror:4-way diagonal mirror:" + "8-way mirror"; ret[2].ival = params->symm; ret[3].name = "Difficulty"; ret[3].type = C_CHOICES; - ret[3].sval = ":Trivial:Basic:Intermediate:Advanced:Unreasonable"; + ret[3].sval = ":Trivial:Basic:Intermediate:Advanced:Extreme:Unreasonable"; ret[3].ival = params->diff; ret[4].name = NULL; @@ -302,286 +325,26 @@ static game_params *custom_params(config_item *cfg) return ret; } -static char *validate_params(game_params *params) +static char *validate_params(game_params *params, int full) { if (params->c < 2 || params->r < 2) return "Both dimensions must be at least 2"; if (params->c > ORDER_MAX || params->r > ORDER_MAX) return "Dimensions greater than "STR(ORDER_MAX)" are not supported"; + if ((params->c * params->r) > 36) + return "Unable to support more than 36 distinct symbols in a puzzle"; return NULL; } /* ---------------------------------------------------------------------- - * Full recursive Solo solver. - * - * The algorithm for this solver is shamelessly copied from a - * Python solver written by Andrew Wilkinson (which is GPLed, but - * I've reused only ideas and no code). It mostly just does the - * obvious recursive thing: pick an empty square, put one of the - * possible digits in it, recurse until all squares are filled, - * backtrack and change some choices if necessary. - * - * The clever bit is that every time it chooses which square to - * fill in next, it does so by counting the number of _possible_ - * numbers that can go in each square, and it prioritises so that - * it picks a square with the _lowest_ number of possibilities. The - * idea is that filling in lots of the obvious bits (particularly - * any squares with only one possibility) will cut down on the list - * of possibilities for other squares and hence reduce the enormous - * search space as much as possible as early as possible. - * - * In practice the algorithm appeared to work very well; run on - * sample problems from the Times it completed in well under a - * second on my G5 even when written in Python, and given an empty - * grid (so that in principle it would enumerate _all_ solved - * grids!) it found the first valid solution just as quickly. So - * with a bit more randomisation I see no reason not to use this as - * my grid generator. - */ - -/* - * Internal data structure used in solver to keep track of - * progress. - */ -struct rsolve_coord { int x, y, r; }; -struct rsolve_usage { - int c, r, cr; /* cr == c*r */ - /* grid is a copy of the input grid, modified as we go along */ - digit *grid; - /* row[y*cr+n-1] TRUE if digit n has been placed in row y */ - unsigned char *row; - /* col[x*cr+n-1] TRUE if digit n has been placed in row x */ - unsigned char *col; - /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */ - unsigned char *blk; - /* This lists all the empty spaces remaining in the grid. */ - struct rsolve_coord *spaces; - int nspaces; - /* If we need randomisation in the solve, this is our random state. */ - random_state *rs; - /* Number of solutions so far found, and maximum number we care about. */ - int solns, maxsolns; -}; - -/* - * The real recursive step in the solving function. - */ -static void rsolve_real(struct rsolve_usage *usage, digit *grid) -{ - int c = usage->c, r = usage->r, cr = usage->cr; - int i, j, n, sx, sy, bestm, bestr; - int *digits; - - /* - * Firstly, check for completion! If there are no spaces left - * in the grid, we have a solution. - */ - if (usage->nspaces == 0) { - if (!usage->solns) { - /* - * This is our first solution, so fill in the output grid. - */ - memcpy(grid, usage->grid, cr * cr); - } - usage->solns++; - return; - } - - /* - * Otherwise, there must be at least one space. Find the most - * constrained space, using the `r' field as a tie-breaker. - */ - bestm = cr+1; /* so that any space will beat it */ - bestr = 0; - i = sx = sy = -1; - for (j = 0; j < usage->nspaces; j++) { - int x = usage->spaces[j].x, y = usage->spaces[j].y; - int m; - - /* - * Find the number of digits that could go in this space. - */ - m = 0; - for (n = 0; n < cr; n++) - if (!usage->row[y*cr+n] && !usage->col[x*cr+n] && - !usage->blk[((y/c)*c+(x/r))*cr+n]) - m++; - - if (m < bestm || (m == bestm && usage->spaces[j].r < bestr)) { - bestm = m; - bestr = usage->spaces[j].r; - sx = x; - sy = y; - i = j; - } - } - - /* - * Swap that square into the final place in the spaces array, - * so that decrementing nspaces will remove it from the list. - */ - if (i != usage->nspaces-1) { - struct rsolve_coord t; - t = usage->spaces[usage->nspaces-1]; - usage->spaces[usage->nspaces-1] = usage->spaces[i]; - usage->spaces[i] = t; - } - - /* - * Now we've decided which square to start our recursion at, - * simply go through all possible values, shuffling them - * randomly first if necessary. - */ - digits = snewn(bestm, int); - j = 0; - for (n = 0; n < cr; n++) - if (!usage->row[sy*cr+n] && !usage->col[sx*cr+n] && - !usage->blk[((sy/c)*c+(sx/r))*cr+n]) { - digits[j++] = n+1; - } - - if (usage->rs) { - /* shuffle */ - for (i = j; i > 1; i--) { - int p = random_upto(usage->rs, i); - if (p != i-1) { - int t = digits[p]; - digits[p] = digits[i-1]; - digits[i-1] = t; - } - } - } - - /* And finally, go through the digit list and actually recurse. */ - for (i = 0; i < j; i++) { - n = digits[i]; - - /* Update the usage structure to reflect the placing of this digit. */ - usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = - usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = TRUE; - usage->grid[sy*cr+sx] = n; - usage->nspaces--; - - /* Call the solver recursively. */ - rsolve_real(usage, grid); - - /* - * If we have seen as many solutions as we need, terminate - * all processing immediately. - */ - if (usage->solns >= usage->maxsolns) - break; - - /* Revert the usage structure. */ - usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = - usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = FALSE; - usage->grid[sy*cr+sx] = 0; - usage->nspaces++; - } - - sfree(digits); -} - -/* - * Entry point to solver. You give it dimensions and a starting - * grid, which is simply an array of N^4 digits. In that array, 0 - * means an empty square, and 1..N mean a clue square. - * - * Return value is the number of solutions found; searching will - * stop after the provided `max'. (Thus, you can pass max==1 to - * indicate that you only care about finding _one_ solution, or - * max==2 to indicate that you want to know the difference between - * a unique and non-unique solution.) The input parameter `grid' is - * also filled in with the _first_ (or only) solution found by the - * solver. - */ -static int rsolve(int c, int r, digit *grid, random_state *rs, int max) -{ - struct rsolve_usage *usage; - int x, y, cr = c*r; - int ret; - - /* - * Create an rsolve_usage structure. - */ - usage = snew(struct rsolve_usage); - - usage->c = c; - usage->r = r; - usage->cr = cr; - - usage->grid = snewn(cr * cr, digit); - memcpy(usage->grid, grid, cr * cr); - - usage->row = snewn(cr * cr, unsigned char); - usage->col = snewn(cr * cr, unsigned char); - usage->blk = snewn(cr * cr, unsigned char); - memset(usage->row, FALSE, cr * cr); - memset(usage->col, FALSE, cr * cr); - memset(usage->blk, FALSE, cr * cr); - - usage->spaces = snewn(cr * cr, struct rsolve_coord); - usage->nspaces = 0; - - usage->solns = 0; - usage->maxsolns = max; - - usage->rs = rs; - - /* - * Now fill it in with data from the input grid. - */ - for (y = 0; y < cr; y++) { - for (x = 0; x < cr; x++) { - int v = grid[y*cr+x]; - if (v == 0) { - usage->spaces[usage->nspaces].x = x; - usage->spaces[usage->nspaces].y = y; - if (rs) - usage->spaces[usage->nspaces].r = random_bits(rs, 31); - else - usage->spaces[usage->nspaces].r = usage->nspaces; - usage->nspaces++; - } else { - usage->row[y*cr+v-1] = TRUE; - usage->col[x*cr+v-1] = TRUE; - usage->blk[((y/c)*c+(x/r))*cr+v-1] = TRUE; - } - } - } - - /* - * Run the real recursive solving function. - */ - rsolve_real(usage, grid); - ret = usage->solns; - - /* - * Clean up the usage structure now we have our answer. - */ - sfree(usage->spaces); - sfree(usage->blk); - sfree(usage->col); - sfree(usage->row); - sfree(usage->grid); - sfree(usage); - - /* - * And return. - */ - return ret; -} - -/* ---------------------------------------------------------------------- - * End of recursive solver code. - */ - -/* ---------------------------------------------------------------------- - * Less capable non-recursive solver. This one is used to check - * solubility of a grid as we gradually remove numbers from it: by - * verifying a grid using this solver we can ensure it isn't _too_ - * hard (e.g. does not actually require guessing and backtracking). - * + * Solver. + * + * This solver is used for two purposes: + * + to check solubility of a grid as we gradually remove numbers + * from it + * + to solve an externally generated puzzle when the user selects + * `Solve'. + * * It supports a variety of specific modes of reasoning. By * enabling or disabling subsets of these modes we can arrange a * range of difficulty levels. @@ -627,6 +390,34 @@ static int rsolve(int c, int r, digit *grid, random_state *rs, int max) * places, found by taking the _complement_ of the union of * the numbers' possible positions (or the spaces' possible * contents). + * + * - Mutual neighbour elimination: find two squares A,B and a + * number N in the possible set of A, such that putting N in A + * would rule out enough possibilities from the mutual + * neighbours of A and B that there would be no possibilities + * left for B. Thereby rule out N in A. + * + The simplest case of this is if B has two possibilities + * (wlog {1,2}), and there are two mutual neighbours of A and + * B which have possibilities {1,3} and {2,3}. Thus, if A + * were to be 3, then those neighbours would contain 1 and 2, + * and hence there would be nothing left which could go in B. + * + There can be more complex cases of it too: if A and B are + * in the same column of large blocks, then they can have + * more than two mutual neighbours, some of which can also be + * neighbours of one another. Suppose, for example, that B + * has possibilities {1,2,3}; there's one square P in the + * same column as B and the same block as A, with + * possibilities {1,4}; and there are _two_ squares Q,R in + * the same column as A and the same block as B with + * possibilities {2,3,4}. Then if A contained 4, P would + * contain 1, and Q and R would have to contain 2 and 3 in + * _some_ order; therefore, once again, B would have no + * remaining possibilities. + * + * - Recursion. If all else fails, we pick one of the currently + * most constrained empty squares and take a random guess at its + * contents, then continue solving on that basis and see if we + * get any further. */ /* @@ -645,7 +436,7 @@ static int rsolve(int c, int r, digit *grid, random_state *rs, int max) #define YTRANS(y) (((y)%c)*r+(y)/c) #define YUNTRANS(y) (((y)%r)*c+(y)/r) -struct nsolve_usage { +struct solver_usage { int c, r, cr; /* * We set up a cubic array, indexed by x, y and digit; each @@ -681,7 +472,7 @@ struct nsolve_usage { * a particular number in it. The y-coordinate passed in here is * transformed. */ -static void nsolve_place(struct nsolve_usage *usage, int x, int y, int n) +static void solver_place(struct solver_usage *usage, int x, int y, int n) { int c = usage->c, r = usage->r, cr = usage->cr; int i, j, bx, by; @@ -732,7 +523,7 @@ static void nsolve_place(struct nsolve_usage *usage, int x, int y, int n) usage->blk[((y%r)*c+(x/r))*cr+n-1] = TRUE; } -static int nsolve_elim(struct nsolve_usage *usage, int start, int step +static int solver_elim(struct solver_usage *usage, int start, int step #ifdef STANDALONE_SOLVER , char *fmt, ... #endif @@ -766,22 +557,36 @@ static int nsolve_elim(struct nsolve_usage *usage, int start, int step #ifdef STANDALONE_SOLVER if (solver_show_working) { va_list ap; + printf("%*s", solver_recurse_depth*4, ""); va_start(ap, fmt); vprintf(fmt, ap); va_end(ap); - printf(":\n placing %d at (%d,%d)\n", - n, 1+x, 1+YUNTRANS(y)); + printf(":\n%*s placing %d at (%d,%d)\n", + solver_recurse_depth*4, "", n, 1+x, 1+YUNTRANS(y)); } #endif - nsolve_place(usage, x, y, n); - return TRUE; + solver_place(usage, x, y, n); + return +1; } + } else if (m == 0) { +#ifdef STANDALONE_SOLVER + if (solver_show_working) { + va_list ap; + printf("%*s", solver_recurse_depth*4, ""); + va_start(ap, fmt); + vprintf(fmt, ap); + va_end(ap); + printf(":\n%*s no possibilities available\n", + solver_recurse_depth*4, ""); + } +#endif + return -1; } - return FALSE; + return 0; } -static int nsolve_intersect(struct nsolve_usage *usage, +static int solver_intersect(struct solver_usage *usage, int start1, int step1, int start2, int step2 #ifdef STANDALONE_SOLVER , char *fmt, ... @@ -800,16 +605,16 @@ static int nsolve_intersect(struct nsolve_usage *usage, if (usage->cube[p] && !(p >= start2 && p < start2+cr*step2 && (p - start2) % step2 == 0)) - return FALSE; /* there is, so we can't deduce */ + return 0; /* there is, so we can't deduce */ } /* * We have determined that all set bits in the first domain are * within its overlap with the second. So loop over the second * domain and remove all set bits that aren't also in that - * overlap; return TRUE iff we actually _did_ anything. + * overlap; return +1 iff we actually _did_ anything. */ - ret = FALSE; + ret = 0; for (i = 0; i < cr; i++) { int p = start2+i*step2; if (usage->cube[p] && @@ -821,6 +626,7 @@ static int nsolve_intersect(struct nsolve_usage *usage, if (!ret) { va_list ap; + printf("%*s", solver_recurse_depth*4, ""); va_start(ap, fmt); vprintf(fmt, ap); va_end(ap); @@ -832,11 +638,11 @@ static int nsolve_intersect(struct nsolve_usage *usage, px = py / cr; py %= cr; - printf(" ruling out %d at (%d,%d)\n", - pn, 1+px, 1+YUNTRANS(py)); + printf("%*s ruling out %d at (%d,%d)\n", + solver_recurse_depth*4, "", pn, 1+px, 1+YUNTRANS(py)); } #endif - ret = TRUE; /* we did something */ + ret = +1; /* we did something */ usage->cube[p] = 0; } } @@ -844,7 +650,16 @@ static int nsolve_intersect(struct nsolve_usage *usage, return ret; } -static int nsolve_set(struct nsolve_usage *usage, +struct solver_scratch { + unsigned char *grid, *rowidx, *colidx, *set; + int *neighbours, *bfsqueue; +#ifdef STANDALONE_SOLVER + int *bfsprev; +#endif +}; + +static int solver_set(struct solver_usage *usage, + struct solver_scratch *scratch, int start, int step1, int step2 #ifdef STANDALONE_SOLVER , char *fmt, ... @@ -853,10 +668,10 @@ static int nsolve_set(struct nsolve_usage *usage, { int c = usage->c, r = usage->r, cr = c*r; int i, j, n, count; - unsigned char *grid = snewn(cr*cr, unsigned char); - unsigned char *rowidx = snewn(cr, unsigned char); - unsigned char *colidx = snewn(cr, unsigned char); - unsigned char *set = snewn(cr, unsigned char); + unsigned char *grid = scratch->grid; + unsigned char *rowidx = scratch->rowidx; + unsigned char *colidx = scratch->colidx; + unsigned char *set = scratch->set; /* * We are passed a cr-by-cr matrix of booleans. Our first job @@ -871,14 +686,15 @@ static int nsolve_set(struct nsolve_usage *usage, for (j = 0; j < cr; j++) if (usage->cube[start+i*step1+j*step2]) first = j, count++; - if (count == 0) { - /* - * This condition actually marks a completely insoluble - * (i.e. internally inconsistent) puzzle. We return and - * report no progress made. - */ - return FALSE; - } + + /* + * If count == 0, then there's a row with no 1s at all and + * the puzzle is internally inconsistent. However, we ought + * to have caught this already during the simpler reasoning + * methods, so we can safely fail an assertion if we reach + * this point here. + */ + assert(count > 0); if (count == 1) rowidx[i] = colidx[first] = FALSE; } @@ -944,7 +760,22 @@ static int nsolve_set(struct nsolve_usage *usage, * indicates a faulty deduction before this point or * even a bogus clue. */ - assert(rows <= n - count); + if (rows > n - count) { +#ifdef STANDALONE_SOLVER + if (solver_show_working) { + va_list ap; + printf("%*s", solver_recurse_depth*4, + ""); + va_start(ap, fmt); + vprintf(fmt, ap); + va_end(ap); + printf(":\n%*s contradiction reached\n", + solver_recurse_depth*4, ""); + } +#endif + return -1; + } + if (rows >= n - count) { int progress = FALSE; @@ -952,8 +783,8 @@ static int nsolve_set(struct nsolve_usage *usage, * We've got one! Now, for each row which _doesn't_ * satisfy the criterion, eliminate all its set * bits in the positions _not_ listed in `set'. - * Return TRUE (meaning progress has been made) if - * we successfully eliminated anything at all. + * Return +1 (meaning progress has been made) if we + * successfully eliminated anything at all. * * This involves referring back through * rowidx/colidx in order to work out which actual @@ -974,9 +805,11 @@ static int nsolve_set(struct nsolve_usage *usage, #ifdef STANDALONE_SOLVER if (solver_show_working) { int px, py, pn; - + if (!progress) { va_list ap; + printf("%*s", solver_recurse_depth*4, + ""); va_start(ap, fmt); vprintf(fmt, ap); va_end(ap); @@ -988,7 +821,8 @@ static int nsolve_set(struct nsolve_usage *usage, px = py / cr; py %= cr; - printf(" ruling out %d at (%d,%d)\n", + printf("%*s ruling out %d at (%d,%d)\n", + solver_recurse_depth*4, "", pn, 1+px, 1+YUNTRANS(py)); } #endif @@ -999,11 +833,7 @@ static int nsolve_set(struct nsolve_usage *usage, } if (progress) { - sfree(set); - sfree(colidx); - sfree(rowidx); - sfree(grid); - return TRUE; + return +1; } } } @@ -1021,56 +851,431 @@ static int nsolve_set(struct nsolve_usage *usage, break; /* done */ } - sfree(set); - sfree(colidx); - sfree(rowidx); - sfree(grid); - - return FALSE; + return 0; } -static int nsolve(int c, int r, digit *grid) +/* + * Try to find a number in the possible set of (x1,y1) which can be + * ruled out because it would leave no possibilities for (x2,y2). + */ +static int solver_mne(struct solver_usage *usage, + struct solver_scratch *scratch, + int x1, int y1, int x2, int y2) { - struct nsolve_usage *usage; - int cr = c*r; - int x, y, n; - int diff = DIFF_BLOCK; + int c = usage->c, r = usage->r, cr = c*r; + int *nb[2]; + unsigned char *set = scratch->set; + unsigned char *numbers = scratch->rowidx; + unsigned char *numbersleft = scratch->colidx; + int nnb, count; + int i, j, n, nbi; + + nb[0] = scratch->neighbours; + nb[1] = scratch->neighbours + cr; /* - * Set up a usage structure as a clean slate (everything - * possible). + * First, work out the mutual neighbour squares of the two. We + * can assert that they're not actually in the same block, + * which leaves two possibilities: they're in different block + * rows _and_ different block columns (thus their mutual + * neighbours are precisely the other two corners of the + * rectangle), or they're in the same row (WLOG) and different + * columns, in which case their mutual neighbours are the + * column of each block aligned with the other square. + * + * We divide the mutual neighbours into two separate subsets + * nb[0] and nb[1]; squares in the same subset are not only + * adjacent to both our key squares, but are also always + * adjacent to one another. */ - usage = snew(struct nsolve_usage); - usage->c = c; - usage->r = r; - usage->cr = cr; - usage->cube = snewn(cr*cr*cr, unsigned char); - usage->grid = grid; /* write straight back to the input */ - memset(usage->cube, TRUE, cr*cr*cr); + if (x1 / r != x2 / r && y1 % r != y2 % r) { + /* Corners of the rectangle. */ + nnb = 1; + nb[0][0] = cubepos(x2, y1, 1); + nb[1][0] = cubepos(x1, y2, 1); + } else if (x1 / r != x2 / r) { + /* Same row of blocks; different blocks within that row. */ + int x1b = x1 - (x1 % r); + int x2b = x2 - (x2 % r); + + nnb = r; + for (i = 0; i < r; i++) { + nb[0][i] = cubepos(x2b+i, y1, 1); + nb[1][i] = cubepos(x1b+i, y2, 1); + } + } else { + /* Same column of blocks; different blocks within that column. */ + int y1b = y1 % r; + int y2b = y2 % r; - usage->row = snewn(cr * cr, unsigned char); - usage->col = snewn(cr * cr, unsigned char); - usage->blk = snewn(cr * cr, unsigned char); - memset(usage->row, FALSE, cr * cr); - memset(usage->col, FALSE, cr * cr); - memset(usage->blk, FALSE, cr * cr); + assert(y1 % r != y2 % r); - /* - * Place all the clue numbers we are given. - */ - for (x = 0; x < cr; x++) - for (y = 0; y < cr; y++) - if (grid[y*cr+x]) - nsolve_place(usage, x, YTRANS(y), grid[y*cr+x]); + nnb = c; + for (i = 0; i < c; i++) { + nb[0][i] = cubepos(x2, y1b+i*r, 1); + nb[1][i] = cubepos(x1, y2b+i*r, 1); + } + } /* - * Now loop over the grid repeatedly trying all permitted modes - * of reasoning. The loop terminates if we complete an - * iteration without making any progress; we then return - * failure or success depending on whether the grid is full or - * not. + * Right. Now loop over each possible number. */ - while (1) { + for (n = 1; n <= cr; n++) { + if (!cube(x1, y1, n)) + continue; + for (j = 0; j < cr; j++) + numbersleft[j] = cube(x2, y2, j+1); + + /* + * Go over every possible subset of each neighbour list, + * and see if its union of possible numbers minus n has the + * same size as the subset. If so, add the numbers in that + * subset to the set of things which would be ruled out + * from (x2,y2) if n were placed at (x1,y1). + */ + memset(set, 0, nnb); + count = 0; + while (1) { + /* + * Binary increment: change the rightmost 0 to a 1, and + * change all 1s to the right of it to 0s. + */ + i = nnb; + while (i > 0 && set[i-1]) + set[--i] = 0, count--; + if (i > 0) + set[--i] = 1, count++; + else + break; /* done */ + + /* + * Examine this subset of each neighbour set. + */ + for (nbi = 0; nbi < 2; nbi++) { + int *nbs = nb[nbi]; + + memset(numbers, 0, cr); + + for (i = 0; i < nnb; i++) + if (set[i]) + for (j = 0; j < cr; j++) + if (j != n-1 && usage->cube[nbs[i] + j]) + numbers[j] = 1; + + for (i = j = 0; j < cr; j++) + i += numbers[j]; + + if (i == count) { + /* + * Got one. This subset of nbs, in the absence + * of n, would definitely contain all the + * numbers listed in `numbers'. Rule them out + * of `numbersleft'. + */ + for (j = 0; j < cr; j++) + if (numbers[j]) + numbersleft[j] = 0; + } + } + } + + /* + * If we've got nothing left in `numbersleft', we have a + * successful mutual neighbour elimination. + */ + for (j = 0; j < cr; j++) + if (numbersleft[j]) + break; + + if (j == cr) { +#ifdef STANDALONE_SOLVER + if (solver_show_working) { + printf("%*smutual neighbour elimination, (%d,%d) vs (%d,%d):\n", + solver_recurse_depth*4, "", + 1+x1, 1+YUNTRANS(y1), 1+x2, 1+YUNTRANS(y2)); + printf("%*s ruling out %d at (%d,%d)\n", + solver_recurse_depth*4, "", + n, 1+x1, 1+YUNTRANS(y1)); + } +#endif + cube(x1, y1, n) = FALSE; + return +1; + } + } + + return 0; /* nothing found */ +} + +/* + * Look for forcing chains. A forcing chain is a path of + * pairwise-exclusive squares (i.e. each pair of adjacent squares + * in the path are in the same row, column or block) with the + * following properties: + * + * (a) Each square on the path has precisely two possible numbers. + * + * (b) Each pair of squares which are adjacent on the path share + * at least one possible number in common. + * + * (c) Each square in the middle of the path shares _both_ of its + * numbers with at least one of its neighbours (not the same + * one with both neighbours). + * + * These together imply that at least one of the possible number + * choices at one end of the path forces _all_ the rest of the + * numbers along the path. In order to make real use of this, we + * need further properties: + * + * (c) Ruling out some number N from the square at one end + * of the path forces the square at the other end to + * take number N. + * + * (d) The two end squares are both in line with some third + * square. + * + * (e) That third square currently has N as a possibility. + * + * If we can find all of that lot, we can deduce that at least one + * of the two ends of the forcing chain has number N, and that + * therefore the mutually adjacent third square does not. + * + * To find forcing chains, we're going to start a bfs at each + * suitable square, once for each of its two possible numbers. + */ +static int solver_forcing(struct solver_usage *usage, + struct solver_scratch *scratch) +{ + int c = usage->c, r = usage->r, cr = c*r; + int *bfsqueue = scratch->bfsqueue; +#ifdef STANDALONE_SOLVER + int *bfsprev = scratch->bfsprev; +#endif + unsigned char *number = scratch->grid; + int *neighbours = scratch->neighbours; + int x, y; + + for (y = 0; y < cr; y++) + for (x = 0; x < cr; x++) { + int count, t, n; + + /* + * If this square doesn't have exactly two candidate + * numbers, don't try it. + * + * In this loop we also sum the candidate numbers, + * which is a nasty hack to allow us to quickly find + * `the other one' (since we will shortly know there + * are exactly two). + */ + for (count = t = 0, n = 1; n <= cr; n++) + if (cube(x, y, n)) + count++, t += n; + if (count != 2) + continue; + + /* + * Now attempt a bfs for each candidate. + */ + for (n = 1; n <= cr; n++) + if (cube(x, y, n)) { + int orign, currn, head, tail; + + /* + * Begin a bfs. + */ + orign = n; + + memset(number, cr+1, cr*cr); + head = tail = 0; + bfsqueue[tail++] = y*cr+x; +#ifdef STANDALONE_SOLVER + bfsprev[y*cr+x] = -1; +#endif + number[y*cr+x] = t - n; + + while (head < tail) { + int xx, yy, nneighbours, xt, yt, xblk, i; + + xx = bfsqueue[head++]; + yy = xx / cr; + xx %= cr; + + currn = number[yy*cr+xx]; + + /* + * Find neighbours of yy,xx. + */ + nneighbours = 0; + for (yt = 0; yt < cr; yt++) + neighbours[nneighbours++] = yt*cr+xx; + for (xt = 0; xt < cr; xt++) + neighbours[nneighbours++] = yy*cr+xt; + xblk = xx - (xx % r); + for (yt = yy % r; yt < cr; yt += r) + for (xt = xblk; xt < xblk+r; xt++) + neighbours[nneighbours++] = yt*cr+xt; + + /* + * Try visiting each of those neighbours. + */ + for (i = 0; i < nneighbours; i++) { + int cc, tt, nn; + + xt = neighbours[i] % cr; + yt = neighbours[i] / cr; + + /* + * We need this square to not be + * already visited, and to include + * currn as a possible number. + */ + if (number[yt*cr+xt] <= cr) + continue; + if (!cube(xt, yt, currn)) + continue; + + /* + * Don't visit _this_ square a second + * time! + */ + if (xt == xx && yt == yy) + continue; + + /* + * To continue with the bfs, we need + * this square to have exactly two + * possible numbers. + */ + for (cc = tt = 0, nn = 1; nn <= cr; nn++) + if (cube(xt, yt, nn)) + cc++, tt += nn; + if (cc == 2) { + bfsqueue[tail++] = yt*cr+xt; +#ifdef STANDALONE_SOLVER + bfsprev[yt*cr+xt] = yy*cr+xx; +#endif + number[yt*cr+xt] = tt - currn; + } + + /* + * One other possibility is that this + * might be the square in which we can + * make a real deduction: if it's + * adjacent to x,y, and currn is equal + * to the original number we ruled out. + */ + if (currn == orign && + (xt == x || yt == y || + (xt / r == x / r && yt % r == y % r))) { +#ifdef STANDALONE_SOLVER + if (solver_show_working) { + char *sep = ""; + int xl, yl; + printf("%*sforcing chain, %d at ends of ", + solver_recurse_depth*4, "", orign); + xl = xx; + yl = yy; + while (1) { + printf("%s(%d,%d)", sep, 1+xl, + 1+YUNTRANS(yl)); + xl = bfsprev[yl*cr+xl]; + if (xl < 0) + break; + yl = xl / cr; + xl %= cr; + sep = "-"; + } + printf("\n%*s ruling out %d at (%d,%d)\n", + solver_recurse_depth*4, "", + orign, 1+xt, 1+YUNTRANS(yt)); + } +#endif + cube(xt, yt, orign) = FALSE; + return 1; + } + } + } + } + } + + return 0; +} + +static struct solver_scratch *solver_new_scratch(struct solver_usage *usage) +{ + struct solver_scratch *scratch = snew(struct solver_scratch); + int cr = usage->cr; + scratch->grid = snewn(cr*cr, unsigned char); + scratch->rowidx = snewn(cr, unsigned char); + scratch->colidx = snewn(cr, unsigned char); + scratch->set = snewn(cr, unsigned char); + scratch->neighbours = snewn(3*cr, int); + scratch->bfsqueue = snewn(cr*cr, int); +#ifdef STANDALONE_SOLVER + scratch->bfsprev = snewn(cr*cr, int); +#endif + return scratch; +} + +static void solver_free_scratch(struct solver_scratch *scratch) +{ +#ifdef STANDALONE_SOLVER + sfree(scratch->bfsprev); +#endif + sfree(scratch->bfsqueue); + sfree(scratch->neighbours); + sfree(scratch->set); + sfree(scratch->colidx); + sfree(scratch->rowidx); + sfree(scratch->grid); + sfree(scratch); +} + +static int solver(int c, int r, digit *grid, int maxdiff) +{ + struct solver_usage *usage; + struct solver_scratch *scratch; + int cr = c*r; + int x, y, x2, y2, n, ret; + int diff = DIFF_BLOCK; + + /* + * Set up a usage structure as a clean slate (everything + * possible). + */ + usage = snew(struct solver_usage); + usage->c = c; + usage->r = r; + usage->cr = cr; + usage->cube = snewn(cr*cr*cr, unsigned char); + usage->grid = grid; /* write straight back to the input */ + memset(usage->cube, TRUE, cr*cr*cr); + + usage->row = snewn(cr * cr, unsigned char); + usage->col = snewn(cr * cr, unsigned char); + usage->blk = snewn(cr * cr, unsigned char); + memset(usage->row, FALSE, cr * cr); + memset(usage->col, FALSE, cr * cr); + memset(usage->blk, FALSE, cr * cr); + + scratch = solver_new_scratch(usage); + + /* + * Place all the clue numbers we are given. + */ + for (x = 0; x < cr; x++) + for (y = 0; y < cr; y++) + if (grid[y*cr+x]) + solver_place(usage, x, YTRANS(y), grid[y*cr+x]); + + /* + * Now loop over the grid repeatedly trying all permitted modes + * of reasoning. The loop terminates if we complete an + * iteration without making any progress; we then return + * failure or success depending on whether the grid is full or + * not. + */ + while (1) { /* * I'd like to write `continue;' inside each of the * following loops, so that the solver returns here after @@ -1086,45 +1291,64 @@ static int nsolve(int c, int r, digit *grid) for (x = 0; x < cr; x += r) for (y = 0; y < r; y++) for (n = 1; n <= cr; n++) - if (!usage->blk[(y*c+(x/r))*cr+n-1] && - nsolve_elim(usage, cubepos(x,y,n), r*cr + if (!usage->blk[(y*c+(x/r))*cr+n-1]) { + ret = solver_elim(usage, cubepos(x,y,n), r*cr #ifdef STANDALONE_SOLVER - , "positional elimination," - " block (%d,%d)", 1+x/r, 1+y + , "positional elimination," + " %d in block (%d,%d)", n, 1+x/r, 1+y #endif - )) { - diff = max(diff, DIFF_BLOCK); - goto cont; + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_BLOCK); + goto cont; + } } + if (maxdiff <= DIFF_BLOCK) + break; + /* * Row-wise positional elimination. */ for (y = 0; y < cr; y++) for (n = 1; n <= cr; n++) - if (!usage->row[y*cr+n-1] && - nsolve_elim(usage, cubepos(0,y,n), cr*cr + if (!usage->row[y*cr+n-1]) { + ret = solver_elim(usage, cubepos(0,y,n), cr*cr #ifdef STANDALONE_SOLVER - , "positional elimination," - " row %d", 1+YUNTRANS(y) + , "positional elimination," + " %d in row %d", n, 1+YUNTRANS(y) #endif - )) { - diff = max(diff, DIFF_SIMPLE); - goto cont; + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_SIMPLE); + goto cont; + } } /* * Column-wise positional elimination. */ for (x = 0; x < cr; x++) for (n = 1; n <= cr; n++) - if (!usage->col[x*cr+n-1] && - nsolve_elim(usage, cubepos(x,0,n), cr + if (!usage->col[x*cr+n-1]) { + ret = solver_elim(usage, cubepos(x,0,n), cr #ifdef STANDALONE_SOLVER - , "positional elimination," " column %d", 1+x + , "positional elimination," + " %d in column %d", n, 1+x #endif - )) { - diff = max(diff, DIFF_SIMPLE); - goto cont; + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_SIMPLE); + goto cont; + } } /* @@ -1132,39 +1356,50 @@ static int nsolve(int c, int r, digit *grid) */ for (x = 0; x < cr; x++) for (y = 0; y < cr; y++) - if (!usage->grid[YUNTRANS(y)*cr+x] && - nsolve_elim(usage, cubepos(x,y,1), 1 + if (!usage->grid[YUNTRANS(y)*cr+x]) { + ret = solver_elim(usage, cubepos(x,y,1), 1 #ifdef STANDALONE_SOLVER - , "numeric elimination at (%d,%d)", 1+x, - 1+YUNTRANS(y) + , "numeric elimination at (%d,%d)", 1+x, + 1+YUNTRANS(y) #endif - )) { - diff = max(diff, DIFF_SIMPLE); - goto cont; + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_SIMPLE); + goto cont; + } } + if (maxdiff <= DIFF_SIMPLE) + break; + /* * Intersectional analysis, rows vs blocks. */ for (y = 0; y < cr; y++) for (x = 0; x < cr; x += r) for (n = 1; n <= cr; n++) + /* + * solver_intersect() never returns -1. + */ if (!usage->row[y*cr+n-1] && !usage->blk[((y%r)*c+(x/r))*cr+n-1] && - (nsolve_intersect(usage, cubepos(0,y,n), cr*cr, + (solver_intersect(usage, cubepos(0,y,n), cr*cr, cubepos(x,y%r,n), r*cr #ifdef STANDALONE_SOLVER , "intersectional analysis," - " row %d vs block (%d,%d)", - 1+YUNTRANS(y), 1+x/r, 1+y%r + " %d in row %d vs block (%d,%d)", + n, 1+YUNTRANS(y), 1+x/r, 1+y%r #endif ) || - nsolve_intersect(usage, cubepos(x,y%r,n), r*cr, + solver_intersect(usage, cubepos(x,y%r,n), r*cr, cubepos(0,y,n), cr*cr #ifdef STANDALONE_SOLVER , "intersectional analysis," - " block (%d,%d) vs row %d", - 1+x/r, 1+y%r, 1+YUNTRANS(y) + " %d in block (%d,%d) vs row %d", + n, 1+x/r, 1+y%r, 1+YUNTRANS(y) #endif ))) { diff = max(diff, DIFF_INTERSECT); @@ -1179,88 +1414,546 @@ static int nsolve(int c, int r, digit *grid) for (n = 1; n <= cr; n++) if (!usage->col[x*cr+n-1] && !usage->blk[(y*c+(x/r))*cr+n-1] && - (nsolve_intersect(usage, cubepos(x,0,n), cr, + (solver_intersect(usage, cubepos(x,0,n), cr, cubepos((x/r)*r,y,n), r*cr #ifdef STANDALONE_SOLVER , "intersectional analysis," - " column %d vs block (%d,%d)", - 1+x, 1+x/r, 1+y + " %d in column %d vs block (%d,%d)", + n, 1+x, 1+x/r, 1+y #endif ) || - nsolve_intersect(usage, cubepos((x/r)*r,y,n), r*cr, + solver_intersect(usage, cubepos((x/r)*r,y,n), r*cr, cubepos(x,0,n), cr #ifdef STANDALONE_SOLVER , "intersectional analysis," - " block (%d,%d) vs column %d", - 1+x/r, 1+y, 1+x + " %d in block (%d,%d) vs column %d", + n, 1+x/r, 1+y, 1+x #endif ))) { diff = max(diff, DIFF_INTERSECT); goto cont; } + if (maxdiff <= DIFF_INTERSECT) + break; + /* * Blockwise set elimination. */ for (x = 0; x < cr; x += r) - for (y = 0; y < r; y++) - if (nsolve_set(usage, cubepos(x,y,1), r*cr, 1 + for (y = 0; y < r; y++) { + ret = solver_set(usage, scratch, cubepos(x,y,1), r*cr, 1 #ifdef STANDALONE_SOLVER - , "set elimination, block (%d,%d)", 1+x/r, 1+y + , "set elimination, block (%d,%d)", 1+x/r, 1+y #endif - )) { - diff = max(diff, DIFF_SET); - goto cont; - } + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_SET); + goto cont; + } + } /* * Row-wise set elimination. */ - for (y = 0; y < cr; y++) - if (nsolve_set(usage, cubepos(0,y,1), cr*cr, 1 + for (y = 0; y < cr; y++) { + ret = solver_set(usage, scratch, cubepos(0,y,1), cr*cr, 1 #ifdef STANDALONE_SOLVER - , "set elimination, row %d", 1+YUNTRANS(y) + , "set elimination, row %d", 1+YUNTRANS(y) #endif - )) { - diff = max(diff, DIFF_SET); - goto cont; - } + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_SET); + goto cont; + } + } /* * Column-wise set elimination. */ - for (x = 0; x < cr; x++) - if (nsolve_set(usage, cubepos(x,0,1), cr, 1 + for (x = 0; x < cr; x++) { + ret = solver_set(usage, scratch, cubepos(x,0,1), cr, 1 #ifdef STANDALONE_SOLVER - , "set elimination, column %d", 1+x + , "set elimination, column %d", 1+x #endif - )) { - diff = max(diff, DIFF_SET); - goto cont; - } + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_SET); + goto cont; + } + } + + /* + * Row-vs-column set elimination on a single number. + */ + for (n = 1; n <= cr; n++) { + ret = solver_set(usage, scratch, cubepos(0,0,n), cr*cr, cr +#ifdef STANDALONE_SOLVER + , "positional set elimination, number %d", n +#endif + ); + if (ret < 0) { + diff = DIFF_IMPOSSIBLE; + goto got_result; + } else if (ret > 0) { + diff = max(diff, DIFF_EXTREME); + goto cont; + } + } + + /* + * Mutual neighbour elimination. + */ + for (y = 0; y+1 < cr; y++) { + for (x = 0; x+1 < cr; x++) { + for (y2 = y+1; y2 < cr; y2++) { + for (x2 = x+1; x2 < cr; x2++) { + /* + * Can't do mutual neighbour elimination + * between elements of the same actual + * block. + */ + if (x/r == x2/r && y%r == y2%r) + continue; + + /* + * Otherwise, try (x,y) vs (x2,y2) in both + * directions, and likewise (x2,y) vs + * (x,y2). + */ + if (!usage->grid[YUNTRANS(y)*cr+x] && + !usage->grid[YUNTRANS(y2)*cr+x2] && + (solver_mne(usage, scratch, x, y, x2, y2) || + solver_mne(usage, scratch, x2, y2, x, y))) { + diff = max(diff, DIFF_EXTREME); + goto cont; + } + if (!usage->grid[YUNTRANS(y)*cr+x2] && + !usage->grid[YUNTRANS(y2)*cr+x] && + (solver_mne(usage, scratch, x2, y, x, y2) || + solver_mne(usage, scratch, x, y2, x2, y))) { + diff = max(diff, DIFF_EXTREME); + goto cont; + } + } + } + } + } + + /* + * Forcing chains. + */ + if (solver_forcing(usage, scratch)) { + diff = max(diff, DIFF_EXTREME); + goto cont; + } + + /* + * If we reach here, we have made no deductions in this + * iteration, so the algorithm terminates. + */ + break; + } + + /* + * Last chance: if we haven't fully solved the puzzle yet, try + * recursing based on guesses for a particular square. We pick + * one of the most constrained empty squares we can find, which + * has the effect of pruning the search tree as much as + * possible. + */ + if (maxdiff >= DIFF_RECURSIVE) { + int best, bestcount; + + best = -1; + bestcount = cr+1; + + for (y = 0; y < cr; y++) + for (x = 0; x < cr; x++) + if (!grid[y*cr+x]) { + int count; + + /* + * An unfilled square. Count the number of + * possible digits in it. + */ + count = 0; + for (n = 1; n <= cr; n++) + if (cube(x,YTRANS(y),n)) + count++; + + /* + * We should have found any impossibilities + * already, so this can safely be an assert. + */ + assert(count > 1); + + if (count < bestcount) { + bestcount = count; + best = y*cr+x; + } + } + + if (best != -1) { + int i, j; + digit *list, *ingrid, *outgrid; + + diff = DIFF_IMPOSSIBLE; /* no solution found yet */ + + /* + * Attempt recursion. + */ + y = best / cr; + x = best % cr; + + list = snewn(cr, digit); + ingrid = snewn(cr * cr, digit); + outgrid = snewn(cr * cr, digit); + memcpy(ingrid, grid, cr * cr); + + /* Make a list of the possible digits. */ + for (j = 0, n = 1; n <= cr; n++) + if (cube(x,YTRANS(y),n)) + list[j++] = n; + +#ifdef STANDALONE_SOLVER + if (solver_show_working) { + char *sep = ""; + printf("%*srecursing on (%d,%d) [", + solver_recurse_depth*4, "", x, y); + for (i = 0; i < j; i++) { + printf("%s%d", sep, list[i]); + sep = " or "; + } + printf("]\n"); + } +#endif + + /* + * And step along the list, recursing back into the + * main solver at every stage. + */ + for (i = 0; i < j; i++) { + int ret; + + memcpy(outgrid, ingrid, cr * cr); + outgrid[y*cr+x] = list[i]; + +#ifdef STANDALONE_SOLVER + if (solver_show_working) + printf("%*sguessing %d at (%d,%d)\n", + solver_recurse_depth*4, "", list[i], x, y); + solver_recurse_depth++; +#endif + + ret = solver(c, r, outgrid, maxdiff); + +#ifdef STANDALONE_SOLVER + solver_recurse_depth--; + if (solver_show_working) { + printf("%*sretracting %d at (%d,%d)\n", + solver_recurse_depth*4, "", list[i], x, y); + } +#endif + + /* + * If we have our first solution, copy it into the + * grid we will return. + */ + if (diff == DIFF_IMPOSSIBLE && ret != DIFF_IMPOSSIBLE) + memcpy(grid, outgrid, cr*cr); + + if (ret == DIFF_AMBIGUOUS) + diff = DIFF_AMBIGUOUS; + else if (ret == DIFF_IMPOSSIBLE) + /* do not change our return value */; + else { + /* the recursion turned up exactly one solution */ + if (diff == DIFF_IMPOSSIBLE) + diff = DIFF_RECURSIVE; + else + diff = DIFF_AMBIGUOUS; + } + + /* + * As soon as we've found more than one solution, + * give up immediately. + */ + if (diff == DIFF_AMBIGUOUS) + break; + } + + sfree(outgrid); + sfree(ingrid); + sfree(list); + } + + } else { + /* + * We're forbidden to use recursion, so we just see whether + * our grid is fully solved, and return DIFF_IMPOSSIBLE + * otherwise. + */ + for (y = 0; y < cr; y++) + for (x = 0; x < cr; x++) + if (!grid[y*cr+x]) + diff = DIFF_IMPOSSIBLE; + } + + got_result:; + +#ifdef STANDALONE_SOLVER + if (solver_show_working) + printf("%*s%s found\n", + solver_recurse_depth*4, "", + diff == DIFF_IMPOSSIBLE ? "no solution" : + diff == DIFF_AMBIGUOUS ? "multiple solutions" : + "one solution"); +#endif + + sfree(usage->cube); + sfree(usage->row); + sfree(usage->col); + sfree(usage->blk); + sfree(usage); + + solver_free_scratch(scratch); + + return diff; +} + +/* ---------------------------------------------------------------------- + * End of solver code. + */ + +/* ---------------------------------------------------------------------- + * Solo filled-grid generator. + * + * This grid generator works by essentially trying to solve a grid + * starting from no clues, and not worrying that there's more than + * one possible solution. Unfortunately, it isn't computationally + * feasible to do this by calling the above solver with an empty + * grid, because that one needs to allocate a lot of scratch space + * at every recursion level. Instead, I have a much simpler + * algorithm which I shamelessly copied from a Python solver + * written by Andrew Wilkinson (which is GPLed, but I've reused + * only ideas and no code). It mostly just does the obvious + * recursive thing: pick an empty square, put one of the possible + * digits in it, recurse until all squares are filled, backtrack + * and change some choices if necessary. + * + * The clever bit is that every time it chooses which square to + * fill in next, it does so by counting the number of _possible_ + * numbers that can go in each square, and it prioritises so that + * it picks a square with the _lowest_ number of possibilities. The + * idea is that filling in lots of the obvious bits (particularly + * any squares with only one possibility) will cut down on the list + * of possibilities for other squares and hence reduce the enormous + * search space as much as possible as early as possible. + */ + +/* + * Internal data structure used in gridgen to keep track of + * progress. + */ +struct gridgen_coord { int x, y, r; }; +struct gridgen_usage { + int c, r, cr; /* cr == c*r */ + /* grid is a copy of the input grid, modified as we go along */ + digit *grid; + /* row[y*cr+n-1] TRUE if digit n has been placed in row y */ + unsigned char *row; + /* col[x*cr+n-1] TRUE if digit n has been placed in row x */ + unsigned char *col; + /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */ + unsigned char *blk; + /* This lists all the empty spaces remaining in the grid. */ + struct gridgen_coord *spaces; + int nspaces; + /* If we need randomisation in the solve, this is our random state. */ + random_state *rs; +}; + +/* + * The real recursive step in the generating function. + */ +static int gridgen_real(struct gridgen_usage *usage, digit *grid) +{ + int c = usage->c, r = usage->r, cr = usage->cr; + int i, j, n, sx, sy, bestm, bestr, ret; + int *digits; + + /* + * Firstly, check for completion! If there are no spaces left + * in the grid, we have a solution. + */ + if (usage->nspaces == 0) { + memcpy(grid, usage->grid, cr * cr); + return TRUE; + } + + /* + * Otherwise, there must be at least one space. Find the most + * constrained space, using the `r' field as a tie-breaker. + */ + bestm = cr+1; /* so that any space will beat it */ + bestr = 0; + i = sx = sy = -1; + for (j = 0; j < usage->nspaces; j++) { + int x = usage->spaces[j].x, y = usage->spaces[j].y; + int m; + + /* + * Find the number of digits that could go in this space. + */ + m = 0; + for (n = 0; n < cr; n++) + if (!usage->row[y*cr+n] && !usage->col[x*cr+n] && + !usage->blk[((y/c)*c+(x/r))*cr+n]) + m++; + + if (m < bestm || (m == bestm && usage->spaces[j].r < bestr)) { + bestm = m; + bestr = usage->spaces[j].r; + sx = x; + sy = y; + i = j; + } + } + + /* + * Swap that square into the final place in the spaces array, + * so that decrementing nspaces will remove it from the list. + */ + if (i != usage->nspaces-1) { + struct gridgen_coord t; + t = usage->spaces[usage->nspaces-1]; + usage->spaces[usage->nspaces-1] = usage->spaces[i]; + usage->spaces[i] = t; + } + + /* + * Now we've decided which square to start our recursion at, + * simply go through all possible values, shuffling them + * randomly first if necessary. + */ + digits = snewn(bestm, int); + j = 0; + for (n = 0; n < cr; n++) + if (!usage->row[sy*cr+n] && !usage->col[sx*cr+n] && + !usage->blk[((sy/c)*c+(sx/r))*cr+n]) { + digits[j++] = n+1; + } + + if (usage->rs) + shuffle(digits, j, sizeof(*digits), usage->rs); + + /* And finally, go through the digit list and actually recurse. */ + ret = FALSE; + for (i = 0; i < j; i++) { + n = digits[i]; + + /* Update the usage structure to reflect the placing of this digit. */ + usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = + usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = TRUE; + usage->grid[sy*cr+sx] = n; + usage->nspaces--; + + /* Call the solver recursively. Stop when we find a solution. */ + if (gridgen_real(usage, grid)) + ret = TRUE; + + /* Revert the usage structure. */ + usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] = + usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = FALSE; + usage->grid[sy*cr+sx] = 0; + usage->nspaces++; + + if (ret) + break; + } + + sfree(digits); + return ret; +} + +/* + * Entry point to generator. You give it dimensions and a starting + * grid, which is simply an array of cr*cr digits. + */ +static void gridgen(int c, int r, digit *grid, random_state *rs) +{ + struct gridgen_usage *usage; + int x, y, cr = c*r; + + /* + * Clear the grid to start with. + */ + memset(grid, 0, cr*cr); + + /* + * Create a gridgen_usage structure. + */ + usage = snew(struct gridgen_usage); + + usage->c = c; + usage->r = r; + usage->cr = cr; + + usage->grid = snewn(cr * cr, digit); + memcpy(usage->grid, grid, cr * cr); + + usage->row = snewn(cr * cr, unsigned char); + usage->col = snewn(cr * cr, unsigned char); + usage->blk = snewn(cr * cr, unsigned char); + memset(usage->row, FALSE, cr * cr); + memset(usage->col, FALSE, cr * cr); + memset(usage->blk, FALSE, cr * cr); + + usage->spaces = snewn(cr * cr, struct gridgen_coord); + usage->nspaces = 0; + + usage->rs = rs; - /* - * If we reach here, we have made no deductions in this - * iteration, so the algorithm terminates. - */ - break; + /* + * Initialise the list of grid spaces. + */ + for (y = 0; y < cr; y++) { + for (x = 0; x < cr; x++) { + usage->spaces[usage->nspaces].x = x; + usage->spaces[usage->nspaces].y = y; + usage->spaces[usage->nspaces].r = random_bits(rs, 31); + usage->nspaces++; + } } - sfree(usage->cube); - sfree(usage->row); - sfree(usage->col); + /* + * Run the real generator function. + */ + gridgen_real(usage, grid); + + /* + * Clean up the usage structure now we have our answer. + */ + sfree(usage->spaces); sfree(usage->blk); + sfree(usage->col); + sfree(usage->row); + sfree(usage->grid); sfree(usage); - - for (x = 0; x < cr; x++) - for (y = 0; y < cr; y++) - if (!grid[y*cr+x]) - return DIFF_IMPOSSIBLE; - return diff; } /* ---------------------------------------------------------------------- - * End of non-recursive solver code. + * End of grid generator code. */ /* @@ -1327,88 +2020,113 @@ static int check_valid(int c, int r, digit *grid) return TRUE; } -static void symmetry_limit(game_params *params, int *xlim, int *ylim, int s) +static int symmetries(game_params *params, int x, int y, int *output, int s) { int c = params->c, r = params->r, cr = c*r; + int i = 0; + +#define ADD(x,y) (*output++ = (x), *output++ = (y), i++) + + ADD(x, y); switch (s) { case SYMM_NONE: - *xlim = *ylim = cr; - break; + break; /* just x,y is all we need */ case SYMM_ROT2: - *xlim = (cr+1) / 2; - *ylim = cr; - break; - case SYMM_REF4: + ADD(cr - 1 - x, cr - 1 - y); + break; case SYMM_ROT4: - *xlim = *ylim = (cr+1) / 2; - break; + ADD(cr - 1 - y, x); + ADD(y, cr - 1 - x); + ADD(cr - 1 - x, cr - 1 - y); + break; + case SYMM_REF2: + ADD(cr - 1 - x, y); + break; + case SYMM_REF2D: + ADD(y, x); + break; + case SYMM_REF4: + ADD(cr - 1 - x, y); + ADD(x, cr - 1 - y); + ADD(cr - 1 - x, cr - 1 - y); + break; + case SYMM_REF4D: + ADD(y, x); + ADD(cr - 1 - x, cr - 1 - y); + ADD(cr - 1 - y, cr - 1 - x); + break; + case SYMM_REF8: + ADD(cr - 1 - x, y); + ADD(x, cr - 1 - y); + ADD(cr - 1 - x, cr - 1 - y); + ADD(y, x); + ADD(y, cr - 1 - x); + ADD(cr - 1 - y, x); + ADD(cr - 1 - y, cr - 1 - x); + break; } + +#undef ADD + + return i; } -static int symmetries(game_params *params, int x, int y, int *output, int s) +static char *encode_solve_move(int cr, digit *grid) { - int c = params->c, r = params->r, cr = c*r; - int i = 0; + int i, len; + char *ret, *p, *sep; - *output++ = x; - *output++ = y; - i++; + /* + * It's surprisingly easy to work out _exactly_ how long this + * string needs to be. To decimal-encode all the numbers from 1 + * to n: + * + * - every number has a units digit; total is n. + * - all numbers above 9 have a tens digit; total is max(n-9,0). + * - all numbers above 99 have a hundreds digit; total is max(n-99,0). + * - and so on. + */ + len = 0; + for (i = 1; i <= cr; i *= 10) + len += max(cr - i + 1, 0); + len += cr; /* don't forget the commas */ + len *= cr; /* there are cr rows of these */ - switch (s) { - case SYMM_NONE: - break; /* just x,y is all we need */ - case SYMM_REF4: - case SYMM_ROT4: - switch (s) { - case SYMM_REF4: - *output++ = cr - 1 - x; - *output++ = y; - i++; - - *output++ = x; - *output++ = cr - 1 - y; - i++; - break; - case SYMM_ROT4: - *output++ = cr - 1 - y; - *output++ = x; - i++; - - *output++ = y; - *output++ = cr - 1 - x; - i++; - break; - } - /* fall through */ - case SYMM_ROT2: - *output++ = cr - 1 - x; - *output++ = cr - 1 - y; - i++; - break; + /* + * Now len is one bigger than the total size of the + * comma-separated numbers (because we counted an + * additional leading comma). We need to have a leading S + * and a trailing NUL, so we're off by one in total. + */ + len++; + + ret = snewn(len, char); + p = ret; + *p++ = 'S'; + sep = ""; + for (i = 0; i < cr*cr; i++) { + p += sprintf(p, "%s%d", sep, grid[i]); + sep = ","; } + *p++ = '\0'; + assert(p - ret == len); - return i; + return ret; } -struct game_aux_info { - int c, r; - digit *grid; -}; - static char *new_game_desc(game_params *params, random_state *rs, - game_aux_info **aux) + char **aux, int interactive) { int c = params->c, r = params->r, cr = c*r; int area = cr*cr; digit *grid, *grid2; struct xy { int x, y; } *locs; int nlocs; - int ret; char *desc; int coords[16], ncoords; - int xlim, ylim; - int maxdiff, recursing; + int maxdiff; + int x, y, i, j; /* * Adjust the maximum difficulty level to be consistent with @@ -1431,108 +2149,85 @@ static char *new_game_desc(game_params *params, random_state *rs, */ do { /* - * Start the recursive solver with an empty grid to generate a - * random solved state. + * Generate a random solved state. */ - memset(grid, 0, area); - ret = rsolve(c, r, grid, rs, 1); - assert(ret == 1); + gridgen(c, r, grid, rs); assert(check_valid(c, r, grid)); /* - * Save the solved grid in the aux_info. + * Save the solved grid in aux. */ { - game_aux_info *ai = snew(game_aux_info); - ai->c = c; - ai->r = r; - ai->grid = snewn(cr * cr, digit); - memcpy(ai->grid, grid, cr * cr * sizeof(digit)); - *aux = ai; + /* + * We might already have written *aux the last time we + * went round this loop, in which case we should free + * the old aux before overwriting it with the new one. + */ + if (*aux) { + sfree(*aux); + } + + *aux = encode_solve_move(cr, grid); } /* * Now we have a solved grid, start removing things from it * while preserving solubility. */ - symmetry_limit(params, &xlim, &ylim, params->symm); - recursing = FALSE; - while (1) { - int x, y, i, j; - /* - * Iterate over the grid and enumerate all the filled - * squares we could empty. - */ - nlocs = 0; - - for (x = 0; x < xlim; x++) - for (y = 0; y < ylim; y++) - if (grid[y*cr+x]) { - locs[nlocs].x = x; - locs[nlocs].y = y; - nlocs++; - } + /* + * Find the set of equivalence classes of squares permitted + * by the selected symmetry. We do this by enumerating all + * the grid squares which have no symmetric companion + * sorting lower than themselves. + */ + nlocs = 0; + for (y = 0; y < cr; y++) + for (x = 0; x < cr; x++) { + int i = y*cr+x; + int j; - /* - * Now shuffle that list. - */ - for (i = nlocs; i > 1; i--) { - int p = random_upto(rs, i); - if (p != i-1) { - struct xy t = locs[p]; - locs[p] = locs[i-1]; - locs[i-1] = t; + ncoords = symmetries(params, x, y, coords, params->symm); + for (j = 0; j < ncoords; j++) + if (coords[2*j+1]*cr+coords[2*j] < i) + break; + if (j == ncoords) { + locs[nlocs].x = x; + locs[nlocs].y = y; + nlocs++; } } - /* - * Now loop over the shuffled list and, for each element, - * see whether removing that element (and its reflections) - * from the grid will still leave the grid soluble by - * nsolve. - */ - for (i = 0; i < nlocs; i++) { - int ret; - - x = locs[i].x; - y = locs[i].y; + /* + * Now shuffle that list. + */ + shuffle(locs, nlocs, sizeof(*locs), rs); - memcpy(grid2, grid, area); - ncoords = symmetries(params, x, y, coords, params->symm); - for (j = 0; j < ncoords; j++) - grid2[coords[2*j+1]*cr+coords[2*j]] = 0; + /* + * Now loop over the shuffled list and, for each element, + * see whether removing that element (and its reflections) + * from the grid will still leave the grid soluble. + */ + for (i = 0; i < nlocs; i++) { + int ret; - if (recursing) - ret = (rsolve(c, r, grid2, NULL, 2) == 1); - else - ret = (nsolve(c, r, grid2) <= maxdiff); + x = locs[i].x; + y = locs[i].y; - if (ret) { - for (j = 0; j < ncoords; j++) - grid[coords[2*j+1]*cr+coords[2*j]] = 0; - break; - } - } + memcpy(grid2, grid, area); + ncoords = symmetries(params, x, y, coords, params->symm); + for (j = 0; j < ncoords; j++) + grid2[coords[2*j+1]*cr+coords[2*j]] = 0; - if (i == nlocs) { - /* - * There was nothing we could remove without - * destroying solvability. If we're trying to - * generate a recursion-only grid and haven't - * switched over to rsolve yet, we now do; - * otherwise we give up. - */ - if (maxdiff == DIFF_RECURSIVE && !recursing) { - recursing = TRUE; - } else { - break; - } + ret = solver(c, r, grid2, maxdiff); + if (ret <= maxdiff) { + for (j = 0; j < ncoords; j++) + grid[coords[2*j+1]*cr+coords[2*j]] = 0; } } memcpy(grid2, grid, area); - } while (nsolve(c, r, grid2) < maxdiff); + } while (solver(c, r, grid2, maxdiff) < maxdiff); sfree(grid2); sfree(locs); @@ -1586,12 +2281,6 @@ static char *new_game_desc(game_params *params, random_state *rs, return desc; } -static void game_free_aux_info(game_aux_info *aux) -{ - sfree(aux->grid); - sfree(aux); -} - static char *validate_desc(game_params *params, char *desc) { int area = params->r * params->r * params->c * params->c; @@ -1604,6 +2293,9 @@ static char *validate_desc(game_params *params, char *desc) } else if (n == '_') { /* do nothing */; } else if (n > '0' && n <= '9') { + int val = atoi(desc-1); + if (val < 1 || val > params->c * params->r) + return "Out-of-range number in game description"; squares++; while (*desc >= '0' && *desc <= '9') desc++; @@ -1620,7 +2312,7 @@ static char *validate_desc(game_params *params, char *desc) return NULL; } -static game_state *new_game(game_params *params, char *desc) +static game_state *new_game(midend *me, game_params *params, char *desc) { game_state *state = snew(game_state); int c = params->c, r = params->r, cr = c*r, area = cr * cr; @@ -1693,39 +2385,41 @@ static void free_game(game_state *state) sfree(state); } -static game_state *solve_game(game_state *state, game_aux_info *ai, - char **error) +static char *solve_game(game_state *state, game_state *currstate, + char *ai, char **error) { - game_state *ret; int c = state->c, r = state->r, cr = c*r; - int rsolve_ret; - - ret = dup_game(state); - ret->completed = ret->cheated = TRUE; + char *ret; + digit *grid; + int solve_ret; /* - * If we already have the solution in the aux_info, save - * ourselves some time. + * If we already have the solution in ai, save ourselves some + * time. */ - if (ai) { + if (ai) + return dupstr(ai); - assert(c == ai->c); - assert(r == ai->r); - memcpy(ret->grid, ai->grid, cr * cr * sizeof(digit)); + grid = snewn(cr*cr, digit); + memcpy(grid, state->grid, cr*cr); + solve_ret = solver(c, r, grid, DIFF_RECURSIVE); - } else { - rsolve_ret = rsolve(c, r, ret->grid, NULL, 2); + *error = NULL; - if (rsolve_ret != 1) { - free_game(ret); - if (rsolve_ret == 0) - *error = "No solution exists for this puzzle"; - else - *error = "Multiple solutions exist for this puzzle"; - return NULL; - } + if (solve_ret == DIFF_IMPOSSIBLE) + *error = "No solution exists for this puzzle"; + else if (solve_ret == DIFF_AMBIGUOUS) + *error = "Multiple solutions exist for this puzzle"; + + if (*error) { + sfree(grid); + return NULL; } + ret = encode_solve_move(cr, grid); + + sfree(grid); + return ret; } @@ -1751,7 +2445,7 @@ static char *grid_text_format(int c, int r, digit *grid) for (x = 0; x < cr; x++) { int ch = grid[y * cr + x]; if (ch == 0) - ch = ' '; + ch = '.'; else if (ch <= 9) ch = '0' + ch; else @@ -1821,51 +2515,107 @@ static void free_ui(game_ui *ui) sfree(ui); } -static game_state *make_move(game_state *from, game_ui *ui, int x, int y, - int button) +static char *encode_ui(game_ui *ui) { - int c = from->c, r = from->r, cr = c*r; + return NULL; +} + +static void decode_ui(game_ui *ui, char *encoding) +{ +} + +static void game_changed_state(game_ui *ui, game_state *oldstate, + game_state *newstate) +{ + int c = newstate->c, r = newstate->r, cr = c*r; + /* + * We prevent pencil-mode highlighting of a filled square. So + * if the user has just filled in a square which we had a + * pencil-mode highlight in (by Undo, or by Redo, or by Solve), + * then we cancel the highlight. + */ + if (ui->hx >= 0 && ui->hy >= 0 && ui->hpencil && + newstate->grid[ui->hy * cr + ui->hx] != 0) { + ui->hx = ui->hy = -1; + } +} + +struct game_drawstate { + int started; + int c, r, cr; + int tilesize; + digit *grid; + unsigned char *pencil; + unsigned char *hl; + /* This is scratch space used within a single call to game_redraw. */ + int *entered_items; +}; + +static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds, + int x, int y, int button) +{ + int c = state->c, r = state->r, cr = c*r; int tx, ty; - game_state *ret; + char buf[80]; button &= ~MOD_MASK; tx = (x + TILE_SIZE - BORDER) / TILE_SIZE - 1; ty = (y + TILE_SIZE - BORDER) / TILE_SIZE - 1; - if (tx >= 0 && tx < cr && ty >= 0 && ty < cr && - (button == LEFT_BUTTON || button == RIGHT_BUTTON)) { - /* - * Prevent pencil-mode highlighting of a filled square. - */ - if (button == RIGHT_BUTTON && from->grid[ty*cr+tx]) - return NULL; - - if (tx == ui->hx && ty == ui->hy) { - ui->hx = ui->hy = -1; - } else { - ui->hx = tx; - ui->hy = ty; - } - ui->hpencil = (button == RIGHT_BUTTON); - return from; /* UI activity occurred */ + if (tx >= 0 && tx < cr && ty >= 0 && ty < cr) { + if (button == LEFT_BUTTON) { + if (state->immutable[ty*cr+tx]) { + ui->hx = ui->hy = -1; + } else if (tx == ui->hx && ty == ui->hy && ui->hpencil == 0) { + ui->hx = ui->hy = -1; + } else { + ui->hx = tx; + ui->hy = ty; + ui->hpencil = 0; + } + return ""; /* UI activity occurred */ + } + if (button == RIGHT_BUTTON) { + /* + * Pencil-mode highlighting for non filled squares. + */ + if (state->grid[ty*cr+tx] == 0) { + if (tx == ui->hx && ty == ui->hy && ui->hpencil) { + ui->hx = ui->hy = -1; + } else { + ui->hpencil = 1; + ui->hx = tx; + ui->hy = ty; + } + } else { + ui->hx = ui->hy = -1; + } + return ""; /* UI activity occurred */ + } } if (ui->hx != -1 && ui->hy != -1 && ((button >= '1' && button <= '9' && button - '0' <= cr) || (button >= 'a' && button <= 'z' && button - 'a' + 10 <= cr) || (button >= 'A' && button <= 'Z' && button - 'A' + 10 <= cr) || - button == ' ')) { + button == ' ' || button == '\010' || button == '\177')) { int n = button - '0'; if (button >= 'A' && button <= 'Z') n = button - 'A' + 10; if (button >= 'a' && button <= 'z') n = button - 'a' + 10; - if (button == ' ') + if (button == ' ' || button == '\010' || button == '\177') n = 0; - if (from->immutable[ui->hy*cr+ui->hx]) - return NULL; /* can't overwrite this square */ + /* + * Can't overwrite this square. In principle this shouldn't + * happen anyway because we should never have even been + * able to highlight the square, but it never hurts to be + * careful. + */ + if (state->immutable[ui->hy*cr+ui->hx]) + return NULL; /* * Can't make pencil marks in a filled square. In principle @@ -1873,16 +2623,57 @@ static game_state *make_move(game_state *from, game_ui *ui, int x, int y, * have even been able to pencil-highlight the square, but * it never hurts to be careful. */ - if (ui->hpencil && from->grid[ui->hy*cr+ui->hx]) + if (ui->hpencil && state->grid[ui->hy*cr+ui->hx]) return NULL; + sprintf(buf, "%c%d,%d,%d", + (char)(ui->hpencil && n > 0 ? 'P' : 'R'), ui->hx, ui->hy, n); + + ui->hx = ui->hy = -1; + + return dupstr(buf); + } + + return NULL; +} + +static game_state *execute_move(game_state *from, char *move) +{ + int c = from->c, r = from->r, cr = c*r; + game_state *ret; + int x, y, n; + + if (move[0] == 'S') { + char *p; + + ret = dup_game(from); + ret->completed = ret->cheated = TRUE; + + p = move+1; + for (n = 0; n < cr*cr; n++) { + ret->grid[n] = atoi(p); + + if (!*p || ret->grid[n] < 1 || ret->grid[n] > cr) { + free_game(ret); + return NULL; + } + + while (*p && isdigit((unsigned char)*p)) p++; + if (*p == ',') p++; + } + + return ret; + } else if ((move[0] == 'P' || move[0] == 'R') && + sscanf(move+1, "%d,%d,%d", &x, &y, &n) == 3 && + x >= 0 && x < cr && y >= 0 && y < cr && n >= 0 && n <= cr) { + ret = dup_game(from); - if (ui->hpencil && n > 0) { - int index = (ui->hy*cr+ui->hx) * cr + (n-1); + if (move[0] == 'P' && n > 0) { + int index = (y*cr+x) * cr + (n-1); ret->pencil[index] = !ret->pencil[index]; } else { - ret->grid[ui->hy*cr+ui->hx] = n; - memset(ret->pencil + (ui->hy*cr+ui->hx)*cr, 0, cr); + ret->grid[y*cr+x] = n; + memset(ret->pencil + (y*cr+x)*cr, 0, cr); /* * We've made a real change to the grid. Check to see @@ -1892,38 +2683,36 @@ static game_state *make_move(game_state *from, game_ui *ui, int x, int y, ret->completed = TRUE; } } - ui->hx = ui->hy = -1; - - return ret; /* made a valid move */ - } - - return NULL; + return ret; + } else + return NULL; /* couldn't parse move string */ } /* ---------------------------------------------------------------------- * Drawing routines. */ -struct game_drawstate { - int started; - int c, r, cr; - digit *grid; - unsigned char *pencil; - unsigned char *hl; -}; - -#define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1) -#define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1) +#define SIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1) +#define GETTILESIZE(cr, w) ( (double)(w-1) / (double)(cr+1) ) -static void game_size(game_params *params, int *x, int *y) +static void game_compute_size(game_params *params, int tilesize, + int *x, int *y) { - int c = params->c, r = params->r, cr = c*r; + /* Ick: fake up `ds->tilesize' for macro expansion purposes */ + struct { int tilesize; } ads, *ds = &ads; + ads.tilesize = tilesize; - *x = XSIZE(cr); - *y = YSIZE(cr); + *x = SIZE(params->c * params->r); + *y = SIZE(params->c * params->r); } -static float *game_colours(frontend *fe, game_state *state, int *ncolours) +static void game_set_size(drawing *dr, game_drawstate *ds, + game_params *params, int tilesize) +{ + ds->tilesize = tilesize; +} + +static float *game_colours(frontend *fe, int *ncolours) { float *ret = snewn(3 * NCOLOURS, float); @@ -1945,6 +2734,10 @@ static float *game_colours(frontend *fe, game_state *state, int *ncolours) ret[COL_HIGHLIGHT * 3 + 1] = 0.85F * ret[COL_BACKGROUND * 3 + 1]; ret[COL_HIGHLIGHT * 3 + 2] = 0.85F * ret[COL_BACKGROUND * 3 + 2]; + ret[COL_ERROR * 3 + 0] = 1.0F; + ret[COL_ERROR * 3 + 1] = 0.0F; + ret[COL_ERROR * 3 + 2] = 0.0F; + ret[COL_PENCIL * 3 + 0] = 0.5F * ret[COL_BACKGROUND * 3 + 0]; ret[COL_PENCIL * 3 + 1] = 0.5F * ret[COL_BACKGROUND * 3 + 1]; ret[COL_PENCIL * 3 + 2] = ret[COL_BACKGROUND * 3 + 2]; @@ -1953,7 +2746,7 @@ static float *game_colours(frontend *fe, game_state *state, int *ncolours) return ret; } -static game_drawstate *game_new_drawstate(game_state *state) +static game_drawstate *game_new_drawstate(drawing *dr, game_state *state) { struct game_drawstate *ds = snew(struct game_drawstate); int c = state->c, r = state->r, cr = c*r; @@ -1968,19 +2761,21 @@ static game_drawstate *game_new_drawstate(game_state *state) memset(ds->pencil, 0, cr*cr*cr); ds->hl = snewn(cr*cr, unsigned char); memset(ds->hl, 0, cr*cr); - + ds->entered_items = snewn(cr*cr, int); + ds->tilesize = 0; /* not decided yet */ return ds; } -static void game_free_drawstate(game_drawstate *ds) +static void game_free_drawstate(drawing *dr, game_drawstate *ds) { sfree(ds->hl); sfree(ds->pencil); sfree(ds->grid); + sfree(ds->entered_items); sfree(ds); } -static void draw_number(frontend *fe, game_drawstate *ds, game_state *state, +static void draw_number(drawing *dr, game_drawstate *ds, game_state *state, int x, int y, int hl) { int c = state->c, r = state->r, cr = c*r; @@ -2010,13 +2805,13 @@ static void draw_number(frontend *fe, game_drawstate *ds, game_state *state, if ((y+1) % c) ch++; - clip(fe, cx, cy, cw, ch); + clip(dr, cx, cy, cw, ch); /* background needs erasing */ - draw_rect(fe, cx, cy, cw, ch, hl == 1 ? COL_HIGHLIGHT : COL_BACKGROUND); + draw_rect(dr, cx, cy, cw, ch, (hl & 15) == 1 ? COL_HIGHLIGHT : COL_BACKGROUND); /* pencil-mode highlight */ - if (hl == 2) { + if ((hl & 15) == 2) { int coords[6]; coords[0] = cx; coords[1] = cy; @@ -2024,7 +2819,7 @@ static void draw_number(frontend *fe, game_drawstate *ds, game_state *state, coords[3] = cy; coords[4] = cx; coords[5] = cy+ch/2; - draw_polygon(fe, coords, 3, TRUE, COL_HIGHLIGHT); + draw_polygon(dr, coords, 3, COL_HIGHLIGHT, COL_HIGHLIGHT); } /* new number needs drawing? */ @@ -2033,38 +2828,59 @@ static void draw_number(frontend *fe, game_drawstate *ds, game_state *state, str[0] = state->grid[y*cr+x] + '0'; if (str[0] > '9') str[0] += 'a' - ('9'+1); - draw_text(fe, tx + TILE_SIZE/2, ty + TILE_SIZE/2, + draw_text(dr, tx + TILE_SIZE/2, ty + TILE_SIZE/2, FONT_VARIABLE, TILE_SIZE/2, ALIGN_VCENTRE | ALIGN_HCENTRE, - state->immutable[y*cr+x] ? COL_CLUE : COL_USER, str); + state->immutable[y*cr+x] ? COL_CLUE : (hl & 16) ? COL_ERROR : COL_USER, str); } else { - /* pencil marks required? */ - int i, j; + int i, j, npencil; + int pw, ph, pmax, fontsize; + + /* count the pencil marks required */ + for (i = npencil = 0; i < cr; i++) + if (state->pencil[(y*cr+x)*cr+i]) + npencil++; + + /* + * It's not sensible to arrange pencil marks in the same + * layout as the squares within a block, because this leads + * to the font being too small. Instead, we arrange pencil + * marks in the nearest thing we can to a square layout, + * and we adjust the square layout depending on the number + * of pencil marks in the square. + */ + for (pw = 1; pw * pw < npencil; pw++); + if (pw < 3) pw = 3; /* otherwise it just looks _silly_ */ + ph = (npencil + pw - 1) / pw; + if (ph < 2) ph = 2; /* likewise */ + pmax = max(pw, ph); + fontsize = TILE_SIZE/(pmax*(11-pmax)/8); for (i = j = 0; i < cr; i++) if (state->pencil[(y*cr+x)*cr+i]) { - int dx = j % r, dy = j / r, crm = max(c, r); + int dx = j % pw, dy = j / pw; + str[1] = '\0'; str[0] = i + '1'; if (str[0] > '9') str[0] += 'a' - ('9'+1); - draw_text(fe, tx + (4*dx+3) * TILE_SIZE / (4*r+2), - ty + (4*dy+3) * TILE_SIZE / (4*c+2), - FONT_VARIABLE, TILE_SIZE/(crm*5/4), + draw_text(dr, tx + (4*dx+3) * TILE_SIZE / (4*pw+2), + ty + (4*dy+3) * TILE_SIZE / (4*ph+2), + FONT_VARIABLE, fontsize, ALIGN_VCENTRE | ALIGN_HCENTRE, COL_PENCIL, str); j++; } } - unclip(fe); + unclip(dr); - draw_update(fe, cx, cy, cw, ch); + draw_update(dr, cx, cy, cw, ch); ds->grid[y*cr+x] = state->grid[y*cr+x]; memcpy(ds->pencil+(y*cr+x)*cr, state->pencil+(y*cr+x)*cr, cr); ds->hl[y*cr+x] = hl; } -static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate, +static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate, game_state *state, int dir, game_ui *ui, float animtime, float flashtime) { @@ -2078,36 +2894,65 @@ static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate, * all games should start by drawing a big * background-colour rectangle covering the whole window. */ - draw_rect(fe, 0, 0, XSIZE(cr), YSIZE(cr), COL_BACKGROUND); + draw_rect(dr, 0, 0, SIZE(cr), SIZE(cr), COL_BACKGROUND); /* * Draw the grid. */ for (x = 0; x <= cr; x++) { int thick = (x % r ? 0 : 1); - draw_rect(fe, BORDER + x*TILE_SIZE - thick, BORDER-1, + draw_rect(dr, BORDER + x*TILE_SIZE - thick, BORDER-1, 1+2*thick, cr*TILE_SIZE+3, COL_GRID); } for (y = 0; y <= cr; y++) { int thick = (y % c ? 0 : 1); - draw_rect(fe, BORDER-1, BORDER + y*TILE_SIZE - thick, + draw_rect(dr, BORDER-1, BORDER + y*TILE_SIZE - thick, cr*TILE_SIZE+3, 1+2*thick, COL_GRID); } } /* + * This array is used to keep track of rows, columns and boxes + * which contain a number more than once. + */ + for (x = 0; x < cr * cr; x++) + ds->entered_items[x] = 0; + for (x = 0; x < cr; x++) + for (y = 0; y < cr; y++) { + digit d = state->grid[y*cr+x]; + if (d) { + int box = (x/r)+(y/c)*c; + ds->entered_items[x*cr+d-1] |= ((ds->entered_items[x*cr+d-1] & 1) << 1) | 1; + ds->entered_items[y*cr+d-1] |= ((ds->entered_items[y*cr+d-1] & 4) << 1) | 4; + ds->entered_items[box*cr+d-1] |= ((ds->entered_items[box*cr+d-1] & 16) << 1) | 16; + } + } + + /* * Draw any numbers which need redrawing. */ for (x = 0; x < cr; x++) { for (y = 0; y < cr; y++) { int highlight = 0; + digit d = state->grid[y*cr+x]; + if (flashtime > 0 && (flashtime <= FLASH_TIME/3 || flashtime >= FLASH_TIME*2/3)) highlight = 1; + + /* Highlight active input areas. */ if (x == ui->hx && y == ui->hy) highlight = ui->hpencil ? 2 : 1; - draw_number(fe, ds, state, x, y, highlight); + + /* Mark obvious errors (ie, numbers which occur more than once + * in a single row, column, or box). */ + if (d && ((ds->entered_items[x*cr+d-1] & 2) || + (ds->entered_items[y*cr+d-1] & 8) || + (ds->entered_items[((x/r)+(y/c)*c)*cr+d-1] & 32))) + highlight |= 16; + + draw_number(dr, ds, state, x, y, highlight); } } @@ -2115,7 +2960,7 @@ static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate, * Update the _entire_ grid if necessary. */ if (!ds->started) { - draw_update(fe, 0, 0, XSIZE(cr), YSIZE(cr)); + draw_update(dr, 0, 0, SIZE(cr), SIZE(cr)); ds->started = TRUE; } } @@ -2135,9 +2980,71 @@ static float game_flash_length(game_state *oldstate, game_state *newstate, return 0.0F; } -static int game_wants_statusbar(void) +static int game_timing_state(game_state *state, game_ui *ui) +{ + return TRUE; +} + +static void game_print_size(game_params *params, float *x, float *y) +{ + int pw, ph; + + /* + * I'll use 9mm squares by default. They should be quite big + * for this game, because players will want to jot down no end + * of pencil marks in the squares. + */ + game_compute_size(params, 900, &pw, &ph); + *x = pw / 100.0; + *y = ph / 100.0; +} + +static void game_print(drawing *dr, game_state *state, int tilesize) { - return FALSE; + int c = state->c, r = state->r, cr = c*r; + int ink = print_mono_colour(dr, 0); + int x, y; + + /* Ick: fake up `ds->tilesize' for macro expansion purposes */ + game_drawstate ads, *ds = &ads; + game_set_size(dr, ds, NULL, tilesize); + + /* + * Border. + */ + print_line_width(dr, 3 * TILE_SIZE / 40); + draw_rect_outline(dr, BORDER, BORDER, cr*TILE_SIZE, cr*TILE_SIZE, ink); + + /* + * Grid. + */ + for (x = 1; x < cr; x++) { + print_line_width(dr, (x % r ? 1 : 3) * TILE_SIZE / 40); + draw_line(dr, BORDER+x*TILE_SIZE, BORDER, + BORDER+x*TILE_SIZE, BORDER+cr*TILE_SIZE, ink); + } + for (y = 1; y < cr; y++) { + print_line_width(dr, (y % c ? 1 : 3) * TILE_SIZE / 40); + draw_line(dr, BORDER, BORDER+y*TILE_SIZE, + BORDER+cr*TILE_SIZE, BORDER+y*TILE_SIZE, ink); + } + + /* + * Numbers. + */ + for (y = 0; y < cr; y++) + for (x = 0; x < cr; x++) + if (state->grid[y*cr+x]) { + char str[2]; + str[1] = '\0'; + str[0] = state->grid[y*cr+x] + '0'; + if (str[0] > '9') + str[0] += 'a' - ('9'+1); + draw_text(dr, BORDER + x*TILE_SIZE + TILE_SIZE/2, + BORDER + y*TILE_SIZE + TILE_SIZE/2, + FONT_VARIABLE, TILE_SIZE/2, + ALIGN_VCENTRE | ALIGN_HCENTRE, ink, str); + } } #ifdef COMBINED @@ -2145,7 +3052,7 @@ static int game_wants_statusbar(void) #endif const struct game thegame = { - "Solo", "games.solo", + "Solo", "games.solo", "solo", default_params, game_fetch_preset, decode_params, @@ -2155,7 +3062,6 @@ const struct game thegame = { TRUE, game_configure, custom_params, validate_params, new_game_desc, - game_free_aux_info, validate_desc, new_game, dup_game, @@ -2164,77 +3070,42 @@ const struct game thegame = { TRUE, game_text_format, new_ui, free_ui, - make_move, - game_size, + encode_ui, + decode_ui, + game_changed_state, + interpret_move, + execute_move, + PREFERRED_TILE_SIZE, game_compute_size, game_set_size, game_colours, game_new_drawstate, game_free_drawstate, game_redraw, game_anim_length, game_flash_length, - game_wants_statusbar, + TRUE, FALSE, game_print_size, game_print, + FALSE, /* wants_statusbar */ + FALSE, game_timing_state, + 0, /* flags */ }; #ifdef STANDALONE_SOLVER -/* - * gcc -DSTANDALONE_SOLVER -o solosolver solo.c malloc.c - */ - -void frontend_default_colour(frontend *fe, float *output) {} -void draw_text(frontend *fe, int x, int y, int fonttype, int fontsize, - int align, int colour, char *text) {} -void draw_rect(frontend *fe, int x, int y, int w, int h, int colour) {} -void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour) {} -void draw_polygon(frontend *fe, int *coords, int npoints, - int fill, int colour) {} -void clip(frontend *fe, int x, int y, int w, int h) {} -void unclip(frontend *fe) {} -void start_draw(frontend *fe) {} -void draw_update(frontend *fe, int x, int y, int w, int h) {} -void end_draw(frontend *fe) {} -unsigned long random_bits(random_state *state, int bits) -{ assert(!"Shouldn't get randomness"); return 0; } -unsigned long random_upto(random_state *state, unsigned long limit) -{ assert(!"Shouldn't get randomness"); return 0; } - -void fatal(char *fmt, ...) -{ - va_list ap; - - fprintf(stderr, "fatal error: "); - - va_start(ap, fmt); - vfprintf(stderr, fmt, ap); - va_end(ap); - - fprintf(stderr, "\n"); - exit(1); -} - int main(int argc, char **argv) { game_params *p; game_state *s; - int recurse = TRUE; char *id = NULL, *desc, *err; - int y, x; int grade = FALSE; + int ret; while (--argc > 0) { char *p = *++argv; - if (!strcmp(p, "-r")) { - recurse = TRUE; - } else if (!strcmp(p, "-n")) { - recurse = FALSE; - } else if (!strcmp(p, "-v")) { + if (!strcmp(p, "-v")) { solver_show_working = TRUE; - recurse = FALSE; } else if (!strcmp(p, "-g")) { grade = TRUE; - recurse = FALSE; } else if (*p == '-') { - fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0]); + fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p); return 1; } else { id = p; @@ -2242,7 +3113,7 @@ int main(int argc, char **argv) } if (!id) { - fprintf(stderr, "usage: %s [-n | -r | -g | -v] \n", argv[0]); + fprintf(stderr, "usage: %s [-g | -v] \n", argv[0]); return 1; } @@ -2260,44 +3131,24 @@ int main(int argc, char **argv) fprintf(stderr, "%s: %s\n", argv[0], err); return 1; } - s = new_game(p, desc); - - if (recurse) { - int ret = rsolve(p->c, p->r, s->grid, NULL, 2); - if (ret > 1) { - fprintf(stderr, "%s: rsolve: multiple solutions detected\n", - argv[0]); - } + s = new_game(NULL, p, desc); + + ret = solver(p->c, p->r, s->grid, DIFF_RECURSIVE); + if (grade) { + printf("Difficulty rating: %s\n", + ret==DIFF_BLOCK ? "Trivial (blockwise positional elimination only)": + ret==DIFF_SIMPLE ? "Basic (row/column/number elimination required)": + ret==DIFF_INTERSECT ? "Intermediate (intersectional analysis required)": + ret==DIFF_SET ? "Advanced (set elimination required)": + ret==DIFF_EXTREME ? "Extreme (complex non-recursive techniques required)": + ret==DIFF_RECURSIVE ? "Unreasonable (guesswork and backtracking required)": + ret==DIFF_AMBIGUOUS ? "Ambiguous (multiple solutions exist)": + ret==DIFF_IMPOSSIBLE ? "Impossible (no solution exists)": + "INTERNAL ERROR: unrecognised difficulty code"); } else { - int ret = nsolve(p->c, p->r, s->grid); - if (grade) { - if (ret == DIFF_IMPOSSIBLE) { - /* - * Now resort to rsolve to determine whether it's - * really soluble. - */ - ret = rsolve(p->c, p->r, s->grid, NULL, 2); - if (ret == 0) - ret = DIFF_IMPOSSIBLE; - else if (ret == 1) - ret = DIFF_RECURSIVE; - else - ret = DIFF_AMBIGUOUS; - } - printf("Difficulty rating: %s\n", - ret==DIFF_BLOCK ? "Trivial (blockwise positional elimination only)": - ret==DIFF_SIMPLE ? "Basic (row/column/number elimination required)": - ret==DIFF_INTERSECT ? "Intermediate (intersectional analysis required)": - ret==DIFF_SET ? "Advanced (set elimination required)": - ret==DIFF_RECURSIVE ? "Unreasonable (guesswork and backtracking required)": - ret==DIFF_AMBIGUOUS ? "Ambiguous (multiple solutions exist)": - ret==DIFF_IMPOSSIBLE ? "Impossible (no solution exists)": - "INTERNAL ERROR: unrecognised difficulty code"); - } + printf("%s\n", grid_text_format(p->c, p->r, s->grid)); } - printf("%s\n", grid_text_format(p->c, p->r, s->grid)); - return 0; }