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Diffstat (limited to 'apps/plugins/puzzles/loopy.c')
| -rw-r--r-- | apps/plugins/puzzles/loopy.c | 3688 |
1 files changed, 3688 insertions, 0 deletions
diff --git a/apps/plugins/puzzles/loopy.c b/apps/plugins/puzzles/loopy.c new file mode 100644 index 0000000..a931b31 --- /dev/null +++ b/apps/plugins/puzzles/loopy.c @@ -0,0 +1,3688 @@ +/* + * loopy.c: + * + * An implementation of the Nikoli game 'Loop the loop'. + * (c) Mike Pinna, 2005, 2006 + * Substantially rewritten to allowing for more general types of grid. + * (c) Lambros Lambrou 2008 + * + * vim: set shiftwidth=4 :set textwidth=80: + */ + +/* + * Possible future solver enhancements: + * + * - There's an interesting deductive technique which makes use + * of topology rather than just graph theory. Each _face_ in + * the grid is either inside or outside the loop; you can tell + * that two faces are on the same side of the loop if they're + * separated by a LINE_NO (or, more generally, by a path + * crossing no LINE_UNKNOWNs and an even number of LINE_YESes), + * and on the opposite side of the loop if they're separated by + * a LINE_YES (or an odd number of LINE_YESes and no + * LINE_UNKNOWNs). Oh, and any face separated from the outside + * of the grid by a LINE_YES or a LINE_NO is on the inside or + * outside respectively. So if you can track this for all + * faces, you figure out the state of the line between a pair + * once their relative insideness is known. + * + The way I envisage this working is simply to keep an edsf + * of all _faces_, which indicates whether they're on + * opposite sides of the loop from one another. We also + * include a special entry in the edsf for the infinite + * exterior "face". + * + So, the simple way to do this is to just go through the + * edges: every time we see an edge in a state other than + * LINE_UNKNOWN which separates two faces that aren't in the + * same edsf class, we can rectify that by merging the + * classes. Then, conversely, an edge in LINE_UNKNOWN state + * which separates two faces that _are_ in the same edsf + * class can immediately have its state determined. + * + But you can go one better, if you're prepared to loop + * over all _pairs_ of edges. Suppose we have edges A and B, + * which respectively separate faces A1,A2 and B1,B2. + * Suppose that A,B are in the same edge-edsf class and that + * A1,B1 (wlog) are in the same face-edsf class; then we can + * immediately place A2,B2 into the same face-edsf class (as + * each other, not as A1 and A2) one way round or the other. + * And conversely again, if A1,B1 are in the same face-edsf + * class and so are A2,B2, then we can put A,B into the same + * face-edsf class. + * * Of course, this deduction requires a quadratic-time + * loop over all pairs of edges in the grid, so it should + * be reserved until there's nothing easier left to be + * done. + * + * - The generalised grid support has made me (SGT) notice a + * possible extension to the loop-avoidance code. When you have + * a path of connected edges such that no other edges at all + * are incident on any vertex in the middle of the path - or, + * alternatively, such that any such edges are already known to + * be LINE_NO - then you know those edges are either all + * LINE_YES or all LINE_NO. Hence you can mentally merge the + * entire path into a single long curly edge for the purposes + * of loop avoidance, and look directly at whether or not the + * extreme endpoints of the path are connected by some other + * route. I find this coming up fairly often when I play on the + * octagonal grid setting, so it might be worth implementing in + * the solver. + * + * - (Just a speed optimisation.) Consider some todo list queue where every + * time we modify something we mark it for consideration by other bits of + * the solver, to save iteration over things that have already been done. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <stddef.h> +#include <string.h> +#include "rbassert.h" +#include <ctype.h> +#include <math.h> + +#include "puzzles.h" +#include "tree234.h" +#include "grid.h" +#include "loopgen.h" + +/* Debugging options */ + +/* +#define DEBUG_CACHES +#define SHOW_WORKING +#define DEBUG_DLINES +*/ + +/* ---------------------------------------------------------------------- + * Struct, enum and function declarations + */ + +enum { + COL_BACKGROUND, + COL_FOREGROUND, + COL_LINEUNKNOWN, + COL_HIGHLIGHT, + COL_MISTAKE, + COL_SATISFIED, + COL_FAINT, + NCOLOURS +}; + +struct game_state { + grid *game_grid; /* ref-counted (internally) */ + + /* Put -1 in a face that doesn't get a clue */ + signed char *clues; + + /* Array of line states, to store whether each line is + * YES, NO or UNKNOWN */ + char *lines; + + unsigned char *line_errors; + int exactly_one_loop; + + int solved; + int cheated; + + /* Used in game_text_format(), so that it knows what type of + * grid it's trying to render as ASCII text. */ + int grid_type; +}; + +enum solver_status { + SOLVER_SOLVED, /* This is the only solution the solver could find */ + SOLVER_MISTAKE, /* This is definitely not a solution */ + SOLVER_AMBIGUOUS, /* This _might_ be an ambiguous solution */ + SOLVER_INCOMPLETE /* This may be a partial solution */ +}; + +/* ------ Solver state ------ */ +typedef struct solver_state { + game_state *state; + enum solver_status solver_status; + /* NB looplen is the number of dots that are joined together at a point, ie a + * looplen of 1 means there are no lines to a particular dot */ + int *looplen; + + /* Difficulty level of solver. Used by solver functions that want to + * vary their behaviour depending on the requested difficulty level. */ + int diff; + + /* caches */ + char *dot_yes_count; + char *dot_no_count; + char *face_yes_count; + char *face_no_count; + char *dot_solved, *face_solved; + int *dotdsf; + + /* Information for Normal level deductions: + * For each dline, store a bitmask for whether we know: + * (bit 0) at least one is YES + * (bit 1) at most one is YES */ + char *dlines; + + /* Hard level information */ + int *linedsf; +} solver_state; + +/* + * Difficulty levels. I do some macro ickery here to ensure that my + * enum and the various forms of my name list always match up. + */ + +#define DIFFLIST(A) \ + A(EASY,Easy,e) \ + A(NORMAL,Normal,n) \ + A(TRICKY,Tricky,t) \ + A(HARD,Hard,h) +#define ENUM(upper,title,lower) DIFF_ ## upper, +#define TITLE(upper,title,lower) #title, +#define ENCODE(upper,title,lower) #lower +#define CONFIG(upper,title,lower) ":" #title +enum { DIFFLIST(ENUM) DIFF_MAX }; +static char const *const diffnames[] = { DIFFLIST(TITLE) }; +static char const diffchars[] = DIFFLIST(ENCODE); +#define DIFFCONFIG DIFFLIST(CONFIG) + +/* + * Solver routines, sorted roughly in order of computational cost. + * The solver will run the faster deductions first, and slower deductions are + * only invoked when the faster deductions are unable to make progress. + * Each function is associated with a difficulty level, so that the generated + * puzzles are solvable by applying only the functions with the chosen + * difficulty level or lower. + */ +#define SOLVERLIST(A) \ + A(trivial_deductions, DIFF_EASY) \ + A(dline_deductions, DIFF_NORMAL) \ + A(linedsf_deductions, DIFF_HARD) \ + A(loop_deductions, DIFF_EASY) +#define SOLVER_FN_DECL(fn,diff) static int fn(solver_state *); +#define SOLVER_FN(fn,diff) &fn, +#define SOLVER_DIFF(fn,diff) diff, +SOLVERLIST(SOLVER_FN_DECL) +static int (*(solver_fns[]))(solver_state *) = { SOLVERLIST(SOLVER_FN) }; +static int const solver_diffs[] = { SOLVERLIST(SOLVER_DIFF) }; +static const int NUM_SOLVERS = sizeof(solver_diffs)/sizeof(*solver_diffs); + +struct game_params { + int w, h; + int diff; + int type; +}; + +/* line_drawstate is the same as line_state, but with the extra ERROR + * possibility. The drawing code copies line_state to line_drawstate, + * except in the case that the line is an error. */ +enum line_state { LINE_YES, LINE_UNKNOWN, LINE_NO }; +enum line_drawstate { DS_LINE_YES, DS_LINE_UNKNOWN, + DS_LINE_NO, DS_LINE_ERROR }; + +#define OPP(line_state) \ + (2 - line_state) + + +struct game_drawstate { + int started; + int tilesize; + int flashing; + int *textx, *texty; + char *lines; + char *clue_error; + char *clue_satisfied; +}; + +static char *validate_desc(const game_params *params, const char *desc); +static int dot_order(const game_state* state, int i, char line_type); +static int face_order(const game_state* state, int i, char line_type); +static solver_state *solve_game_rec(const solver_state *sstate); + +#ifdef DEBUG_CACHES +static void check_caches(const solver_state* sstate); +#else +#define check_caches(s) +#endif + +/* ------- List of grid generators ------- */ +#define GRIDLIST(A) \ + A(Squares,GRID_SQUARE,3,3) \ + A(Triangular,GRID_TRIANGULAR,3,3) \ + A(Honeycomb,GRID_HONEYCOMB,3,3) \ + A(Snub-Square,GRID_SNUBSQUARE,3,3) \ + A(Cairo,GRID_CAIRO,3,4) \ + A(Great-Hexagonal,GRID_GREATHEXAGONAL,3,3) \ + A(Octagonal,GRID_OCTAGONAL,3,3) \ + A(Kites,GRID_KITE,3,3) \ + A(Floret,GRID_FLORET,1,2) \ + A(Dodecagonal,GRID_DODECAGONAL,2,2) \ + A(Great-Dodecagonal,GRID_GREATDODECAGONAL,2,2) \ + A(Penrose (kite/dart),GRID_PENROSE_P2,3,3) \ + A(Penrose (rhombs),GRID_PENROSE_P3,3,3) + +#define GRID_NAME(title,type,amin,omin) #title, +#define GRID_CONFIG(title,type,amin,omin) ":" #title +#define GRID_TYPE(title,type,amin,omin) type, +#define GRID_SIZES(title,type,amin,omin) \ + {amin, omin, \ + "Width and height for this grid type must both be at least " #amin, \ + "At least one of width and height for this grid type must be at least " #omin,}, +static char const *const gridnames[] = { GRIDLIST(GRID_NAME) }; +#define GRID_CONFIGS GRIDLIST(GRID_CONFIG) +static grid_type grid_types[] = { GRIDLIST(GRID_TYPE) }; +#define NUM_GRID_TYPES (sizeof(grid_types) / sizeof(grid_types[0])) +static const struct { + int amin, omin; + char *aerr, *oerr; +} grid_size_limits[] = { GRIDLIST(GRID_SIZES) }; + +/* Generates a (dynamically allocated) new grid, according to the + * type and size requested in params. Does nothing if the grid is already + * generated. */ +static grid *loopy_generate_grid(const game_params *params, + const char *grid_desc) +{ + return grid_new(grid_types[params->type], params->w, params->h, grid_desc); +} + +/* ---------------------------------------------------------------------- + * Preprocessor magic + */ + +/* General constants */ +#define PREFERRED_TILE_SIZE 32 +#define BORDER(tilesize) ((tilesize) / 2) +#define FLASH_TIME 0.5F + +#define BIT_SET(field, bit) ((field) & (1<<(bit))) + +#define SET_BIT(field, bit) (BIT_SET(field, bit) ? FALSE : \ + ((field) |= (1<<(bit)), TRUE)) + +#define CLEAR_BIT(field, bit) (BIT_SET(field, bit) ? \ + ((field) &= ~(1<<(bit)), TRUE) : FALSE) + +#define CLUE2CHAR(c) \ + ((c < 0) ? ' ' : c < 10 ? c + '0' : c - 10 + 'A') + +/* ---------------------------------------------------------------------- + * General struct manipulation and other straightforward code + */ + +static game_state *dup_game(const game_state *state) +{ + game_state *ret = snew(game_state); + + ret->game_grid = state->game_grid; + ret->game_grid->refcount++; + + ret->solved = state->solved; + ret->cheated = state->cheated; + + ret->clues = snewn(state->game_grid->num_faces, signed char); + memcpy(ret->clues, state->clues, state->game_grid->num_faces); + + ret->lines = snewn(state->game_grid->num_edges, char); + memcpy(ret->lines, state->lines, state->game_grid->num_edges); + + ret->line_errors = snewn(state->game_grid->num_edges, unsigned char); + memcpy(ret->line_errors, state->line_errors, state->game_grid->num_edges); + ret->exactly_one_loop = state->exactly_one_loop; + + ret->grid_type = state->grid_type; + return ret; +} + +static void free_game(game_state *state) +{ + if (state) { + grid_free(state->game_grid); + sfree(state->clues); + sfree(state->lines); + sfree(state->line_errors); + sfree(state); + } +} + +static solver_state *new_solver_state(const game_state *state, int diff) { + int i; + int num_dots = state->game_grid->num_dots; + int num_faces = state->game_grid->num_faces; + int num_edges = state->game_grid->num_edges; + solver_state *ret = snew(solver_state); + + ret->state = dup_game(state); + + ret->solver_status = SOLVER_INCOMPLETE; + ret->diff = diff; + + ret->dotdsf = snew_dsf(num_dots); + ret->looplen = snewn(num_dots, int); + + for (i = 0; i < num_dots; i++) { + ret->looplen[i] = 1; + } + + ret->dot_solved = snewn(num_dots, char); + ret->face_solved = snewn(num_faces, char); + memset(ret->dot_solved, FALSE, num_dots); + memset(ret->face_solved, FALSE, num_faces); + + ret->dot_yes_count = snewn(num_dots, char); + memset(ret->dot_yes_count, 0, num_dots); + ret->dot_no_count = snewn(num_dots, char); + memset(ret->dot_no_count, 0, num_dots); + ret->face_yes_count = snewn(num_faces, char); + memset(ret->face_yes_count, 0, num_faces); + ret->face_no_count = snewn(num_faces, char); + memset(ret->face_no_count, 0, num_faces); + + if (diff < DIFF_NORMAL) { + ret->dlines = NULL; + } else { + ret->dlines = snewn(2*num_edges, char); + memset(ret->dlines, 0, 2*num_edges); + } + + if (diff < DIFF_HARD) { + ret->linedsf = NULL; + } else { + ret->linedsf = snew_dsf(state->game_grid->num_edges); + } + + return ret; +} + +static void free_solver_state(solver_state *sstate) { + if (sstate) { + free_game(sstate->state); + sfree(sstate->dotdsf); + sfree(sstate->looplen); + sfree(sstate->dot_solved); + sfree(sstate->face_solved); + sfree(sstate->dot_yes_count); + sfree(sstate->dot_no_count); + sfree(sstate->face_yes_count); + sfree(sstate->face_no_count); + + /* OK, because sfree(NULL) is a no-op */ + sfree(sstate->dlines); + sfree(sstate->linedsf); + + sfree(sstate); + } +} + +static solver_state *dup_solver_state(const solver_state *sstate) { + game_state *state = sstate->state; + int num_dots = state->game_grid->num_dots; + int num_faces = state->game_grid->num_faces; + int num_edges = state->game_grid->num_edges; + solver_state *ret = snew(solver_state); + + ret->state = state = dup_game(sstate->state); + + ret->solver_status = sstate->solver_status; + ret->diff = sstate->diff; + + ret->dotdsf = snewn(num_dots, int); + ret->looplen = snewn(num_dots, int); + memcpy(ret->dotdsf, sstate->dotdsf, + num_dots * sizeof(int)); + memcpy(ret->looplen, sstate->looplen, + num_dots * sizeof(int)); + + ret->dot_solved = snewn(num_dots, char); + ret->face_solved = snewn(num_faces, char); + memcpy(ret->dot_solved, sstate->dot_solved, num_dots); + memcpy(ret->face_solved, sstate->face_solved, num_faces); + + ret->dot_yes_count = snewn(num_dots, char); + memcpy(ret->dot_yes_count, sstate->dot_yes_count, num_dots); + ret->dot_no_count = snewn(num_dots, char); + memcpy(ret->dot_no_count, sstate->dot_no_count, num_dots); + + ret->face_yes_count = snewn(num_faces, char); + memcpy(ret->face_yes_count, sstate->face_yes_count, num_faces); + ret->face_no_count = snewn(num_faces, char); + memcpy(ret->face_no_count, sstate->face_no_count, num_faces); + + if (sstate->dlines) { + ret->dlines = snewn(2*num_edges, char); + memcpy(ret->dlines, sstate->dlines, + 2*num_edges); + } else { + ret->dlines = NULL; + } + + if (sstate->linedsf) { + ret->linedsf = snewn(num_edges, int); + memcpy(ret->linedsf, sstate->linedsf, + num_edges * sizeof(int)); + } else { + ret->linedsf = NULL; + } + + return ret; +} + +static game_params *default_params(void) +{ + game_params *ret = snew(game_params); + +#ifdef SLOW_SYSTEM + ret->h = 7; + ret->w = 7; +#else + ret->h = 10; + ret->w = 10; +#endif + ret->diff = DIFF_EASY; + ret->type = 0; + + return ret; +} + +static game_params *dup_params(const game_params *params) +{ + game_params *ret = snew(game_params); + + *ret = *params; /* structure copy */ + return ret; +} + +static const game_params presets[] = { +#ifdef SMALL_SCREEN + { 7, 7, DIFF_EASY, 0 }, + { 7, 7, DIFF_NORMAL, 0 }, + { 7, 7, DIFF_HARD, 0 }, + { 7, 7, DIFF_HARD, 1 }, + { 7, 7, DIFF_HARD, 2 }, + { 5, 5, DIFF_HARD, 3 }, + { 7, 7, DIFF_HARD, 4 }, + { 5, 4, DIFF_HARD, 5 }, + { 5, 5, DIFF_HARD, 6 }, + { 5, 5, DIFF_HARD, 7 }, + { 3, 3, DIFF_HARD, 8 }, + { 3, 3, DIFF_HARD, 9 }, + { 3, 3, DIFF_HARD, 10 }, + { 6, 6, DIFF_HARD, 11 }, + { 6, 6, DIFF_HARD, 12 }, +#else + { 7, 7, DIFF_EASY, 0 }, + { 10, 10, DIFF_EASY, 0 }, + { 7, 7, DIFF_NORMAL, 0 }, + { 10, 10, DIFF_NORMAL, 0 }, + { 7, 7, DIFF_HARD, 0 }, + { 10, 10, DIFF_HARD, 0 }, + { 10, 10, DIFF_HARD, 1 }, + { 12, 10, DIFF_HARD, 2 }, + { 7, 7, DIFF_HARD, 3 }, + { 9, 9, DIFF_HARD, 4 }, + { 5, 4, DIFF_HARD, 5 }, + { 7, 7, DIFF_HARD, 6 }, + { 5, 5, DIFF_HARD, 7 }, + { 5, 5, DIFF_HARD, 8 }, + { 5, 4, DIFF_HARD, 9 }, + { 5, 4, DIFF_HARD, 10 }, + { 10, 10, DIFF_HARD, 11 }, + { 10, 10, DIFF_HARD, 12 } +#endif +}; + +static int game_fetch_preset(int i, char **name, game_params **params) +{ + game_params *tmppar; + char buf[80]; + + if (i < 0 || i >= lenof(presets)) + return FALSE; + + tmppar = snew(game_params); + *tmppar = presets[i]; + *params = tmppar; + sprintf(buf, "%dx%d %s - %s", tmppar->h, tmppar->w, + gridnames[tmppar->type], diffnames[tmppar->diff]); + *name = dupstr(buf); + + return TRUE; +} + +static void free_params(game_params *params) +{ + sfree(params); +} + +static void decode_params(game_params *params, char const *string) +{ + params->h = params->w = atoi(string); + params->diff = DIFF_EASY; + while (*string && isdigit((unsigned char)*string)) string++; + if (*string == 'x') { + string++; + params->h = atoi(string); + while (*string && isdigit((unsigned char)*string)) string++; + } + if (*string == 't') { + string++; + params->type = atoi(string); + while (*string && isdigit((unsigned char)*string)) string++; + } + if (*string == 'd') { + int i; + string++; + for (i = 0; i < DIFF_MAX; i++) + if (*string == diffchars[i]) + params->diff = i; + if (*string) string++; + } +} + +static char *encode_params(const game_params *params, int full) +{ + char str[80]; + sprintf(str, "%dx%dt%d", params->w, params->h, params->type); + if (full) + sprintf(str + strlen(str), "d%c", diffchars[params->diff]); + return dupstr(str); +} + +static config_item *game_configure(const game_params *params) +{ + config_item *ret; + char buf[80]; + + ret = snewn(5, config_item); + + ret[0].name = "Width"; + ret[0].type = C_STRING; + sprintf(buf, "%d", params->w); + ret[0].sval = dupstr(buf); + ret[0].ival = 0; + + ret[1].name = "Height"; + ret[1].type = C_STRING; + sprintf(buf, "%d", params->h); + ret[1].sval = dupstr(buf); + ret[1].ival = 0; + + ret[2].name = "Grid type"; + ret[2].type = C_CHOICES; + ret[2].sval = GRID_CONFIGS; + ret[2].ival = params->type; + + ret[3].name = "Difficulty"; + ret[3].type = C_CHOICES; + ret[3].sval = DIFFCONFIG; + ret[3].ival = params->diff; + + ret[4].name = NULL; + ret[4].type = C_END; + ret[4].sval = NULL; + ret[4].ival = 0; + + return ret; +} + +static game_params *custom_params(const config_item *cfg) +{ + game_params *ret = snew(game_params); + + ret->w = atoi(cfg[0].sval); + ret->h = atoi(cfg[1].sval); + ret->type = cfg[2].ival; + ret->diff = cfg[3].ival; + + return ret; +} + +static char *validate_params(const game_params *params, int full) +{ + if (params->type < 0 || params->type >= NUM_GRID_TYPES) + return "Illegal grid type"; + if (params->w < grid_size_limits[params->type].amin || + params->h < grid_size_limits[params->type].amin) + return grid_size_limits[params->type].aerr; + if (params->w < grid_size_limits[params->type].omin && + params->h < grid_size_limits[params->type].omin) + return grid_size_limits[params->type].oerr; + + /* + * This shouldn't be able to happen at all, since decode_params + * and custom_params will never generate anything that isn't + * within range. + */ + assert(params->diff < DIFF_MAX); + + return NULL; +} + +/* Returns a newly allocated string describing the current puzzle */ +static char *state_to_text(const game_state *state) +{ + grid *g = state->game_grid; + char *retval; + int num_faces = g->num_faces; + char *description = snewn(num_faces + 1, char); + char *dp = description; + int empty_count = 0; + int i; + + for (i = 0; i < num_faces; i++) { + if (state->clues[i] < 0) { + if (empty_count > 25) { + dp += sprintf(dp, "%c", (int)(empty_count + 'a' - 1)); + empty_count = 0; + } + empty_count++; + } else { + if (empty_count) { + dp += sprintf(dp, "%c", (int)(empty_count + 'a' - 1)); + empty_count = 0; + } + dp += sprintf(dp, "%c", (int)CLUE2CHAR(state->clues[i])); + } + } + + if (empty_count) + dp += sprintf(dp, "%c", (int)(empty_count + 'a' - 1)); + + retval = dupstr(description); + sfree(description); + + return retval; +} + +#define GRID_DESC_SEP '_' + +/* Splits up a (optional) grid_desc from the game desc. Returns the + * grid_desc (which needs freeing) and updates the desc pointer to + * start of real desc, or returns NULL if no desc. */ +static char *extract_grid_desc(const char **desc) +{ + char *sep = strchr(*desc, GRID_DESC_SEP), *gd; + int gd_len; + + if (!sep) return NULL; + + gd_len = sep - (*desc); + gd = snewn(gd_len+1, char); + memcpy(gd, *desc, gd_len); + gd[gd_len] = '\0'; + + *desc = sep+1; + + return gd; +} + +/* We require that the params pass the test in validate_params and that the + * description fills the entire game area */ +static char *validate_desc(const game_params *params, const char *desc) +{ + int count = 0; + grid *g; + char *grid_desc, *ret; + + /* It's pretty inefficient to do this just for validation. All we need to + * know is the precise number of faces. */ + grid_desc = extract_grid_desc(&desc); + ret = grid_validate_desc(grid_types[params->type], params->w, params->h, grid_desc); + if (ret) return ret; + + g = loopy_generate_grid(params, grid_desc); + if (grid_desc) sfree(grid_desc); + + for (; *desc; ++desc) { + if ((*desc >= '0' && *desc <= '9') || (*desc >= 'A' && *desc <= 'Z')) { + count++; + continue; + } + if (*desc >= 'a') { + count += *desc - 'a' + 1; + continue; + } + return "Unknown character in description"; + } + + if (count < g->num_faces) + return "Description too short for board size"; + if (count > g->num_faces) + return "Description too long for board size"; + + grid_free(g); + + return NULL; +} + +/* Sums the lengths of the numbers in range [0,n) */ +/* See equivalent function in solo.c for justification of this. */ +static int len_0_to_n(int n) +{ + int len = 1; /* Counting 0 as a bit of a special case */ + int i; + + for (i = 1; i < n; i *= 10) { + len += max(n - i, 0); + } + + return len; +} + +static char *encode_solve_move(const game_state *state) +{ + int len; + char *ret, *p; + int i; + int num_edges = state->game_grid->num_edges; + + /* This is going to return a string representing the moves needed to set + * every line in a grid to be the same as the ones in 'state'. The exact + * length of this string is predictable. */ + + len = 1; /* Count the 'S' prefix */ + /* Numbers in all lines */ + len += len_0_to_n(num_edges); + /* For each line we also have a letter */ + len += num_edges; + + ret = snewn(len + 1, char); + p = ret; + + p += sprintf(p, "S"); + + for (i = 0; i < num_edges; i++) { + switch (state->lines[i]) { + case LINE_YES: + p += sprintf(p, "%dy", i); + break; + case LINE_NO: + p += sprintf(p, "%dn", i); + break; + } + } + + /* No point in doing sums like that if they're going to be wrong */ + assert(strlen(ret) <= (size_t)len); + return ret; +} + +static game_ui *new_ui(const game_state *state) +{ + return NULL; +} + +static void free_ui(game_ui *ui) +{ +} + +static char *encode_ui(const game_ui *ui) +{ + return NULL; +} + +static void decode_ui(game_ui *ui, const char *encoding) +{ +} + +static void game_changed_state(game_ui *ui, const game_state *oldstate, + const game_state *newstate) +{ +} + +static void game_compute_size(const game_params *params, int tilesize, + int *x, int *y) +{ + int grid_width, grid_height, rendered_width, rendered_height; + int g_tilesize; + + grid_compute_size(grid_types[params->type], params->w, params->h, + &g_tilesize, &grid_width, &grid_height); + + /* multiply first to minimise rounding error on integer division */ + rendered_width = grid_width * tilesize / g_tilesize; + rendered_height = grid_height * tilesize / g_tilesize; + *x = rendered_width + 2 * BORDER(tilesize) + 1; + *y = rendered_height + 2 * BORDER(tilesize) + 1; +} + +static void game_set_size(drawing *dr, game_drawstate *ds, + const game_params *params, int tilesize) +{ + ds->tilesize = tilesize; +} + +static float *game_colours(frontend *fe, int *ncolours) +{ + float *ret = snewn(3 * NCOLOURS, float); + + frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]); + + ret[COL_FOREGROUND * 3 + 0] = 0.0F; + ret[COL_FOREGROUND * 3 + 1] = 0.0F; + ret[COL_FOREGROUND * 3 + 2] = 0.0F; + + /* + * We want COL_LINEUNKNOWN to be a yellow which is a bit darker + * than the background. (I previously set it to 0.8,0.8,0, but + * found that this went badly with the 0.8,0.8,0.8 favoured as a + * background by the Java frontend.) + */ + ret[COL_LINEUNKNOWN * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.9F; + ret[COL_LINEUNKNOWN * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.9F; + ret[COL_LINEUNKNOWN * 3 + 2] = 0.0F; + + ret[COL_HIGHLIGHT * 3 + 0] = 1.0F; + ret[COL_HIGHLIGHT * 3 + 1] = 1.0F; + ret[COL_HIGHLIGHT * 3 + 2] = 1.0F; + + ret[COL_MISTAKE * 3 + 0] = 1.0F; + ret[COL_MISTAKE * 3 + 1] = 0.0F; + ret[COL_MISTAKE * 3 + 2] = 0.0F; + + ret[COL_SATISFIED * 3 + 0] = 0.0F; + ret[COL_SATISFIED * 3 + 1] = 0.0F; + ret[COL_SATISFIED * 3 + 2] = 0.0F; + + /* We want the faint lines to be a bit darker than the background. + * Except if the background is pretty dark already; then it ought to be a + * bit lighter. Oy vey. + */ + ret[COL_FAINT * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.9F; + ret[COL_FAINT * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.9F; + ret[COL_FAINT * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] * 0.9F; + + *ncolours = NCOLOURS; + return ret; +} + +static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state) +{ + struct game_drawstate *ds = snew(struct game_drawstate); + int num_faces = state->game_grid->num_faces; + int num_edges = state->game_grid->num_edges; + int i; + + ds->tilesize = 0; + ds->started = 0; + ds->lines = snewn(num_edges, char); + ds->clue_error = snewn(num_faces, char); + ds->clue_satisfied = snewn(num_faces, char); + ds->textx = snewn(num_faces, int); + ds->texty = snewn(num_faces, int); + ds->flashing = 0; + + memset(ds->lines, LINE_UNKNOWN, num_edges); + memset(ds->clue_error, 0, num_faces); + memset(ds->clue_satisfied, 0, num_faces); + for (i = 0; i < num_faces; i++) + ds->textx[i] = ds->texty[i] = -1; + + return ds; +} + +static void game_free_drawstate(drawing *dr, game_drawstate *ds) +{ + sfree(ds->textx); + sfree(ds->texty); + sfree(ds->clue_error); + sfree(ds->clue_satisfied); + sfree(ds->lines); + sfree(ds); +} + +static int game_timing_state(const game_state *state, game_ui *ui) +{ + return TRUE; +} + +static float game_anim_length(const game_state *oldstate, + const game_state *newstate, int dir, game_ui *ui) +{ + return 0.0F; +} + +static int game_can_format_as_text_now(const game_params *params) +{ + if (params->type != 0) + return FALSE; + return TRUE; +} + +static char *game_text_format(const game_state *state) +{ + int w, h, W, H; + int x, y, i; + int cell_size; + char *ret; + grid *g = state->game_grid; + grid_face *f; + + assert(state->grid_type == 0); + + /* Work out the basic size unit */ + f = g->faces; /* first face */ + assert(f->order == 4); + /* The dots are ordered clockwise, so the two opposite + * corners are guaranteed to span the square */ + cell_size = abs(f->dots[0]->x - f->dots[2]->x); + + w = (g->highest_x - g->lowest_x) / cell_size; + h = (g->highest_y - g->lowest_y) / cell_size; + + /* Create a blank "canvas" to "draw" on */ + W = 2 * w + 2; + H = 2 * h + 1; + ret = snewn(W * H + 1, char); + for (y = 0; y < H; y++) { + for (x = 0; x < W-1; x++) { + ret[y*W + x] = ' '; + } + ret[y*W + W-1] = '\n'; + } + ret[H*W] = '\0'; + + /* Fill in edge info */ + for (i = 0; i < g->num_edges; i++) { + grid_edge *e = g->edges + i; + /* Cell coordinates, from (0,0) to (w-1,h-1) */ + int x1 = (e->dot1->x - g->lowest_x) / cell_size; + int x2 = (e->dot2->x - g->lowest_x) / cell_size; + int y1 = (e->dot1->y - g->lowest_y) / cell_size; + int y2 = (e->dot2->y - g->lowest_y) / cell_size; + /* Midpoint, in canvas coordinates (canvas coordinates are just twice + * cell coordinates) */ + x = x1 + x2; + y = y1 + y2; + switch (state->lines[i]) { + case LINE_YES: + ret[y*W + x] = (y1 == y2) ? '-' : '|'; + break; + case LINE_NO: + ret[y*W + x] = 'x'; + break; + case LINE_UNKNOWN: + break; /* already a space */ + default: + assert(!"Illegal line state"); + } + } + + /* Fill in clues */ + for (i = 0; i < g->num_faces; i++) { + int x1, x2, y1, y2; + + f = g->faces + i; + assert(f->order == 4); + /* Cell coordinates, from (0,0) to (w-1,h-1) */ + x1 = (f->dots[0]->x - g->lowest_x) / cell_size; + x2 = (f->dots[2]->x - g->lowest_x) / cell_size; + y1 = (f->dots[0]->y - g->lowest_y) / cell_size; + y2 = (f->dots[2]->y - g->lowest_y) / cell_size; + /* Midpoint, in canvas coordinates */ + x = x1 + x2; + y = y1 + y2; + ret[y*W + x] = CLUE2CHAR(state->clues[i]); + } + return ret; +} + +/* ---------------------------------------------------------------------- + * Debug code + */ + +#ifdef DEBUG_CACHES +static void check_caches(const solver_state* sstate) +{ + int i; + const game_state *state = sstate->state; + const grid *g = state->game_grid; + + for (i = 0; i < g->num_dots; i++) { + assert(dot_order(state, i, LINE_YES) == sstate->dot_yes_count[i]); + assert(dot_order(state, i, LINE_NO) == sstate->dot_no_count[i]); + } + + for (i = 0; i < g->num_faces; i++) { + assert(face_order(state, i, LINE_YES) == sstate->face_yes_count[i]); + assert(face_order(state, i, LINE_NO) == sstate->face_no_count[i]); + } +} + +#if 0 +#define check_caches(s) \ + do { \ + fprintf(stderr, "check_caches at line %d\n", __LINE__); \ + check_caches(s); \ + } while (0) +#endif +#endif /* DEBUG_CACHES */ + +/* ---------------------------------------------------------------------- + * Solver utility functions + */ + +/* Sets the line (with index i) to the new state 'line_new', and updates + * the cached counts of any affected faces and dots. + * Returns TRUE if this actually changed the line's state. */ +static int solver_set_line(solver_state *sstate, int i, + enum line_state line_new +#ifdef SHOW_WORKING + , const char *reason +#endif + ) +{ + game_state *state = sstate->state; + grid *g; + grid_edge *e; + + assert(line_new != LINE_UNKNOWN); + + check_caches(sstate); + + if (state->lines[i] == line_new) { + return FALSE; /* nothing changed */ + } + state->lines[i] = line_new; + +#ifdef SHOW_WORKING + fprintf(stderr, "solver: set line [%d] to %s (%s)\n", + i, line_new == LINE_YES ? "YES" : "NO", + reason); +#endif + + g = state->game_grid; + e = g->edges + i; + + /* Update the cache for both dots and both faces affected by this. */ + if (line_new == LINE_YES) { + sstate->dot_yes_count[e->dot1 - g->dots]++; + sstate->dot_yes_count[e->dot2 - g->dots]++; + if (e->face1) { + sstate->face_yes_count[e->face1 - g->faces]++; + } + if (e->face2) { + sstate->face_yes_count[e->face2 - g->faces]++; + } + } else { + sstate->dot_no_count[e->dot1 - g->dots]++; + sstate->dot_no_count[e->dot2 - g->dots]++; + if (e->face1) { + sstate->face_no_count[e->face1 - g->faces]++; + } + if (e->face2) { + sstate->face_no_count[e->face2 - g->faces]++; + } + } + + check_caches(sstate); + return TRUE; +} + +#ifdef SHOW_WORKING +#define solver_set_line(a, b, c) \ + solver_set_line(a, b, c, __FUNCTION__) +#endif + +/* + * Merge two dots due to the existence of an edge between them. + * Updates the dsf tracking equivalence classes, and keeps track of + * the length of path each dot is currently a part of. + * Returns TRUE if the dots were already linked, ie if they are part of a + * closed loop, and false otherwise. + */ +static int merge_dots(solver_state *sstate, int edge_index) +{ + int i, j, len; + grid *g = sstate->state->game_grid; + grid_edge *e = g->edges + edge_index; + + i = e->dot1 - g->dots; + j = e->dot2 - g->dots; + + i = dsf_canonify(sstate->dotdsf, i); + j = dsf_canonify(sstate->dotdsf, j); + + if (i == j) { + return TRUE; + } else { + len = sstate->looplen[i] + sstate->looplen[j]; + dsf_merge(sstate->dotdsf, i, j); + i = dsf_canonify(sstate->dotdsf, i); + sstate->looplen[i] = len; + return FALSE; + } +} + +/* Merge two lines because the solver has deduced that they must be either + * identical or opposite. Returns TRUE if this is new information, otherwise + * FALSE. */ +static int merge_lines(solver_state *sstate, int i, int j, int inverse +#ifdef SHOW_WORKING + , const char *reason +#endif + ) +{ + int inv_tmp; + + assert(i < sstate->state->game_grid->num_edges); + assert(j < sstate->state->game_grid->num_edges); + + i = edsf_canonify(sstate->linedsf, i, &inv_tmp); + inverse ^= inv_tmp; + j = edsf_canonify(sstate->linedsf, j, &inv_tmp); + inverse ^= inv_tmp; + + edsf_merge(sstate->linedsf, i, j, inverse); + +#ifdef SHOW_WORKING + if (i != j) { + fprintf(stderr, "%s [%d] [%d] %s(%s)\n", + __FUNCTION__, i, j, + inverse ? "inverse " : "", reason); + } +#endif + return (i != j); +} + +#ifdef SHOW_WORKING +#define merge_lines(a, b, c, d) \ + merge_lines(a, b, c, d, __FUNCTION__) +#endif + +/* Count the number of lines of a particular type currently going into the + * given dot. */ +static int dot_order(const game_state* state, int dot, char line_type) +{ + int n = 0; + grid *g = state->game_grid; + grid_dot *d = g->dots + dot; + int i; + + for (i = 0; i < d->order; i++) { + grid_edge *e = d->edges[i]; + if (state->lines[e - g->edges] == line_type) + ++n; + } + return n; +} + +/* Count the number of lines of a particular type currently surrounding the + * given face */ +static int face_order(const game_state* state, int face, char line_type) +{ + int n = 0; + grid *g = state->game_grid; + grid_face *f = g->faces + face; + int i; + + for (i = 0; i < f->order; i++) { + grid_edge *e = f->edges[i]; + if (state->lines[e - g->edges] == line_type) + ++n; + } + return n; +} + +/* Set all lines bordering a dot of type old_type to type new_type + * Return value tells caller whether this function actually did anything */ +static int dot_setall(solver_state *sstate, int dot, + char old_type, char new_type) +{ + int retval = FALSE, r; + game_state *state = sstate->state; + grid *g; + grid_dot *d; + int i; + + if (old_type == new_type) + return FALSE; + + g = state->game_grid; + d = g->dots + dot; + + for (i = 0; i < d->order; i++) { + int line_index = d->edges[i] - g->edges; + if (state->lines[line_index] == old_type) { + r = solver_set_line(sstate, line_index, new_type); + assert(r == TRUE); + retval = TRUE; + } + } + return retval; +} + +/* Set all lines bordering a face of type old_type to type new_type */ +static int face_setall(solver_state *sstate, int face, + char old_type, char new_type) +{ + int retval = FALSE, r; + game_state *state = sstate->state; + grid *g; + grid_face *f; + int i; + + if (old_type == new_type) + return FALSE; + + g = state->game_grid; + f = g->faces + face; + + for (i = 0; i < f->order; i++) { + int line_index = f->edges[i] - g->edges; + if (state->lines[line_index] == old_type) { + r = solver_set_line(sstate, line_index, new_type); + assert(r == TRUE); + retval = TRUE; + } + } + return retval; +} + +/* ---------------------------------------------------------------------- + * Loop generation and clue removal + */ + +static void add_full_clues(game_state *state, random_state *rs) +{ + signed char *clues = state->clues; + grid *g = state->game_grid; + char *board = snewn(g->num_faces, char); + int i; + + generate_loop(g, board, rs, NULL, NULL); + + /* Fill out all the clues by initialising to 0, then iterating over + * all edges and incrementing each clue as we find edges that border + * between BLACK/WHITE faces. While we're at it, we verify that the + * algorithm does work, and there aren't any GREY faces still there. */ + memset(clues, 0, g->num_faces); + for (i = 0; i < g->num_edges; i++) { + grid_edge *e = g->edges + i; + grid_face *f1 = e->face1; + grid_face *f2 = e->face2; + enum face_colour c1 = FACE_COLOUR(f1); + enum face_colour c2 = FACE_COLOUR(f2); + assert(c1 != FACE_GREY); + assert(c2 != FACE_GREY); + if (c1 != c2) { + if (f1) clues[f1 - g->faces]++; + if (f2) clues[f2 - g->faces]++; + } + } + sfree(board); +} + + +static int game_has_unique_soln(const game_state *state, int diff) +{ + int ret; + solver_state *sstate_new; + solver_state *sstate = new_solver_state((game_state *)state, diff); + + sstate_new = solve_game_rec(sstate); + + assert(sstate_new->solver_status != SOLVER_MISTAKE); + ret = (sstate_new->solver_status == SOLVER_SOLVED); + + free_solver_state(sstate_new); + free_solver_state(sstate); + + return ret; +} + + +/* Remove clues one at a time at random. */ +static game_state *remove_clues(game_state *state, random_state *rs, + int diff) +{ + int *face_list; + int num_faces = state->game_grid->num_faces; + game_state *ret = dup_game(state), *saved_ret; + int n; + + /* We need to remove some clues. We'll do this by forming a list of all + * available clues, shuffling it, then going along one at a + * time clearing each clue in turn for which doing so doesn't render the + * board unsolvable. */ + face_list = snewn(num_faces, int); + for (n = 0; n < num_faces; ++n) { + face_list[n] = n; + } + + shuffle(face_list, num_faces, sizeof(int), rs); + + for (n = 0; n < num_faces; ++n) { + saved_ret = dup_game(ret); + ret->clues[face_list[n]] = -1; + + if (game_has_unique_soln(ret, diff)) { + free_game(saved_ret); + } else { + free_game(ret); + ret = saved_ret; + } + } + sfree(face_list); + + return ret; +} + + +static char *new_game_desc(const game_params *params, random_state *rs, + char **aux, int interactive) +{ + /* solution and description both use run-length encoding in obvious ways */ + char *retval, *game_desc, *grid_desc; + grid *g; + game_state *state = snew(game_state); + game_state *state_new; + + grid_desc = grid_new_desc(grid_types[params->type], params->w, params->h, rs); + state->game_grid = g = loopy_generate_grid(params, grid_desc); + + state->clues = snewn(g->num_faces, signed char); + state->lines = snewn(g->num_edges, char); + state->line_errors = snewn(g->num_edges, unsigned char); + state->exactly_one_loop = FALSE; + + state->grid_type = params->type; + + newboard_please: + + memset(state->lines, LINE_UNKNOWN, g->num_edges); + memset(state->line_errors, 0, g->num_edges); + + state->solved = state->cheated = FALSE; + + /* Get a new random solvable board with all its clues filled in. Yes, this + * can loop for ever if the params are suitably unfavourable, but + * preventing games smaller than 4x4 seems to stop this happening */ + do { + add_full_clues(state, rs); + } while (!game_has_unique_soln(state, params->diff)); + + state_new = remove_clues(state, rs, params->diff); + free_game(state); + state = state_new; + + + if (params->diff > 0 && game_has_unique_soln(state, params->diff-1)) { +#ifdef SHOW_WORKING + fprintf(stderr, "Rejecting board, it is too easy\n"); +#endif + goto newboard_please; + } + + game_desc = state_to_text(state); + + free_game(state); + + if (grid_desc) { + retval = snewn(strlen(grid_desc) + 1 + strlen(game_desc) + 1, char); + sprintf(retval, "%s%c%s", grid_desc, (int)GRID_DESC_SEP, game_desc); + sfree(grid_desc); + sfree(game_desc); + } else { + retval = game_desc; + } + + assert(!validate_desc(params, retval)); + + return retval; +} + +static game_state *new_game(midend *me, const game_params *params, + const char *desc) +{ + int i; + game_state *state = snew(game_state); + int empties_to_make = 0; + int n,n2; + const char *dp; + char *grid_desc; + grid *g; + int num_faces, num_edges; + + grid_desc = extract_grid_desc(&desc); + state->game_grid = g = loopy_generate_grid(params, grid_desc); + if (grid_desc) sfree(grid_desc); + + dp = desc; + + num_faces = g->num_faces; + num_edges = g->num_edges; + + state->clues = snewn(num_faces, signed char); + state->lines = snewn(num_edges, char); + state->line_errors = snewn(num_edges, unsigned char); + state->exactly_one_loop = FALSE; + + state->solved = state->cheated = FALSE; + + state->grid_type = params->type; + + for (i = 0; i < num_faces; i++) { + if (empties_to_make) { + empties_to_make--; + state->clues[i] = -1; + continue; + } + + assert(*dp); + n = *dp - '0'; + n2 = *dp - 'A' + 10; + if (n >= 0 && n < 10) { + state->clues[i] = n; + } else if (n2 >= 10 && n2 < 36) { + state->clues[i] = n2; + } else { + n = *dp - 'a' + 1; + assert(n > 0); + state->clues[i] = -1; + empties_to_make = n - 1; + } + ++dp; + } + + memset(state->lines, LINE_UNKNOWN, num_edges); + memset(state->line_errors, 0, num_edges); + return state; +} + +/* Calculates the line_errors data, and checks if the current state is a + * solution */ +static int check_completion(game_state *state) +{ + grid *g = state->game_grid; + int i, ret; + int *dsf, *component_state; + int nsilly, nloop, npath, largest_comp, largest_size, total_pathsize; + enum { COMP_NONE, COMP_LOOP, COMP_PATH, COMP_SILLY, COMP_EMPTY }; + + memset(state->line_errors, 0, g->num_edges); + + /* + * Find loops in the grid, and determine whether the puzzle is + * solved. + * + * Loopy is a bit more complicated than most puzzles that care + * about loop detection. In most of them, loops are simply + * _forbidden_; so the obviously right way to do + * error-highlighting during play is to light up a graph edge red + * iff it is part of a loop, which is exactly what the centralised + * findloop.c makes easy. + * + * But Loopy is unusual in that you're _supposed_ to be making a + * loop - and yet _some_ loops are not the right loop. So we need + * to be more discriminating, by identifying loops one by one and + * then thinking about which ones to highlight, and so findloop.c + * isn't quite the right tool for the job in this case. + * + * Worse still, consider situations in which the grid contains a + * loop and also some non-loop edges: there are some cases like + * this in which the user's intuitive expectation would be to + * highlight the loop (if you're only about half way through the + * puzzle and have accidentally made a little loop in some corner + * of the grid), and others in which they'd be more likely to + * expect you to highlight the non-loop edges (if you've just + * closed off a whole loop that you thought was the entire + * solution, but forgot some disconnected edges in a corner + * somewhere). So while it's easy enough to check whether the + * solution is _right_, highlighting the wrong parts is a tricky + * problem for this puzzle! + * + * I'd quite like, in some situations, to identify the largest + * loop among the player's YES edges, and then light up everything + * other than that. But finding the longest cycle in a graph is an + * NP-complete problem (because, in particular, it must return a + * Hamilton cycle if one exists). + * + * However, I think we can make the problem tractable by + * exercising the Puzzles principle that it isn't absolutely + * necessary to highlight _all_ errors: the key point is that by + * the time the user has filled in the whole grid, they should + * either have seen a completion flash, or have _some_ error + * highlight showing them why the solution isn't right. So in + * principle it would be *just about* good enough to highlight + * just one error in the whole grid, if there was really no better + * way. But we'd like to highlight as many errors as possible. + * + * In this case, I think the simple approach is to make use of the + * fact that no vertex may have degree > 2, and that's really + * simple to detect. So the plan goes like this: + * + * - Form the dsf of connected components of the graph vertices. + * + * - Highlight an error at any vertex with degree > 2. (It so + * happens that we do this by lighting up all the edges + * incident to that vertex, but that's an output detail.) + * + * - Any component that contains such a vertex is now excluded + * from further consideration, because it already has a + * highlight. + * + * - The remaining components have no vertex with degree > 2, and + * hence they all consist of either a simple loop, or a simple + * path with two endpoints. + * + * - For these purposes, group together all the paths and imagine + * them to be a single component (because in most normal + * situations the player will gradually build up the solution + * _not_ all in one connected segment, but as lots of separate + * little path pieces that gradually connect to each other). + * + * - After doing that, if there is exactly one (sensible) + * component - be it a collection of paths or a loop - then + * highlight no further edge errors. (The former case is normal + * during play, and the latter is a potentially solved puzzle.) + * + * - Otherwise, find the largest of the sensible components, + * leave that one unhighlighted, and light the rest up in red. + */ + + dsf = snew_dsf(g->num_dots); + + /* Build the dsf. */ + for (i = 0; i < g->num_edges; i++) { + if (state->lines[i] == LINE_YES) { + grid_edge *e = g->edges + i; + int d1 = e->dot1 - g->dots, d2 = e->dot2 - g->dots; + dsf_merge(dsf, d1, d2); + } + } + + /* Initialise a state variable for each connected component. */ + component_state = snewn(g->num_dots, int); + for (i = 0; i < g->num_dots; i++) { + if (dsf_canonify(dsf, i) == i) + component_state[i] = COMP_LOOP; + else + component_state[i] = COMP_NONE; + } + + /* Check for dots with degree > 3. Here we also spot dots of + * degree 1 in which the user has marked all the non-edges as + * LINE_NO, because those are also clear vertex-level errors, so + * we give them the same treatment of excluding their connected + * component from the subsequent loop analysis. */ + for (i = 0; i < g->num_dots; i++) { + int comp = dsf_canonify(dsf, i); + int yes = dot_order(state, i, LINE_YES); + int unknown = dot_order(state, i, LINE_UNKNOWN); + if ((yes == 1 && unknown == 0) || (yes >= 3)) { + /* violation, so mark all YES edges as errors */ + grid_dot *d = g->dots + i; + int j; + for (j = 0; j < d->order; j++) { + int e = d->edges[j] - g->edges; + if (state->lines[e] == LINE_YES) + state->line_errors[e] = TRUE; + } + /* And mark this component as not worthy of further + * consideration. */ + component_state[comp] = COMP_SILLY; + + } else if (yes == 0) { + /* A completely isolated dot must also be excluded it from + * the subsequent loop highlighting pass, but we tag it + * with a different enum value to avoid it counting + * towards the components that inhibit returning a win + * status. */ + component_state[comp] = COMP_EMPTY; + } else if (yes == 1) { + /* A dot with degree 1 that didn't fall into the 'clearly + * erroneous' case above indicates that this connected + * component will be a path rather than a loop - unless + * something worse elsewhere in the component has + * classified it as silly. */ + if (component_state[comp] != COMP_SILLY) + component_state[comp] = COMP_PATH; + } + } + + /* Count up the components. Also, find the largest sensible + * component. (Tie-breaking condition is derived from the order of + * vertices in the grid data structure, which is fairly arbitrary + * but at least stays stable throughout the game.) */ + nsilly = nloop = npath = 0; + total_pathsize = 0; + largest_comp = largest_size = -1; + for (i = 0; i < g->num_dots; i++) { + if (component_state[i] == COMP_SILLY) { + nsilly++; + } else if (component_state[i] == COMP_PATH) { + total_pathsize += dsf_size(dsf, i); + npath = 1; + } else if (component_state[i] == COMP_LOOP) { + int this_size; + + nloop++; + + if ((this_size = dsf_size(dsf, i)) > largest_size) { + largest_comp = i; + largest_size = this_size; + } + } + } + if (largest_size < total_pathsize) { + largest_comp = -1; /* means the paths */ + largest_size = total_pathsize; + } + + if (nloop > 0 && nloop + npath > 1) { + /* + * If there are at least two sensible components including at + * least one loop, highlight all edges in every sensible + * component that is not the largest one. + */ + for (i = 0; i < g->num_edges; i++) { + if (state->lines[i] == LINE_YES) { + grid_edge *e = g->edges + i; + int d1 = e->dot1 - g->dots; /* either endpoint is good enough */ + int comp = dsf_canonify(dsf, d1); + if ((component_state[comp] == COMP_PATH && + -1 != largest_comp) || + (component_state[comp] == COMP_LOOP && + comp != largest_comp)) + state->line_errors[i] = TRUE; + } + } + } + + if (nloop == 1 && npath == 0 && nsilly == 0) { + /* + * If there is exactly one component and it is a loop, then + * the puzzle is potentially complete, so check the clues. + */ + ret = TRUE; + + for (i = 0; i < g->num_faces; i++) { + int c = state->clues[i]; + if (c >= 0 && face_order(state, i, LINE_YES) != c) { + ret = FALSE; + break; + } + } + + /* + * Also, whether or not the puzzle is actually complete, set + * the flag that says this game_state has exactly one loop and + * nothing else, which will be used to vary the semantics of + * clue highlighting at display time. + */ + state->exactly_one_loop = TRUE; + } else { + ret = FALSE; + state->exactly_one_loop = FALSE; + } + + sfree(component_state); + sfree(dsf); + + return ret; +} + +/* ---------------------------------------------------------------------- + * Solver logic + * + * Our solver modes operate as follows. Each mode also uses the modes above it. + * + * Easy Mode + * Just implement the rules of the game. + * + * Normal and Tricky Modes + * For each (adjacent) pair of lines through each dot we store a bit for + * whether at least one of them is on and whether at most one is on. (If we + * know both or neither is on that's already stored more directly.) + * + * Advanced Mode + * Use edsf data structure to make equivalence classes of lines that are + * known identical to or opposite to one another. + */ + + +/* DLines: + * For general grids, we consider "dlines" to be pairs of lines joined + * at a dot. The lines must be adjacent around the dot, so we can think of + * a dline as being a dot+face combination. Or, a dot+edge combination where + * the second edge is taken to be the next clockwise edge from the dot. + * Original loopy code didn't have this extra restriction of the lines being + * adjacent. From my tests with square grids, this extra restriction seems to + * take little, if anything, away from the quality of the puzzles. + * A dline can be uniquely identified by an edge/dot combination, given that + * a dline-pair always goes clockwise around its common dot. The edge/dot + * combination can be represented by an edge/bool combination - if bool is + * TRUE, use edge->dot1 else use edge->dot2. So the total number of dlines is + * exactly twice the number of edges in the grid - although the dlines + * spanning the infinite face are not all that useful to the solver. + * Note that, by convention, a dline goes clockwise around its common dot, + * which means the dline goes anti-clockwise around its common face. + */ + +/* Helper functions for obtaining an index into an array of dlines, given + * various information. We assume the grid layout conventions about how + * the various lists are interleaved - see grid_make_consistent() for + * details. */ + +/* i points to the first edge of the dline pair, reading clockwise around + * the dot. */ +static int dline_index_from_dot(grid *g, grid_dot *d, int i) +{ + grid_edge *e = d->edges[i]; + int ret; +#ifdef DEBUG_DLINES + grid_edge *e2; + int i2 = i+1; + if (i2 == d->order) i2 = 0; + e2 = d->edges[i2]; +#endif + ret = 2 * (e - g->edges) + ((e->dot1 == d) ? 1 : 0); +#ifdef DEBUG_DLINES + printf("dline_index_from_dot: d=%d,i=%d, edges [%d,%d] - %d\n", + (int)(d - g->dots), i, (int)(e - g->edges), + (int)(e2 - g->edges), ret); +#endif + return ret; +} +/* i points to the second edge of the dline pair, reading clockwise around + * the face. That is, the edges of the dline, starting at edge{i}, read + * anti-clockwise around the face. By layout conventions, the common dot + * of the dline will be f->dots[i] */ +static int dline_index_from_face(grid *g, grid_face *f, int i) +{ + grid_edge *e = f->edges[i]; + grid_dot *d = f->dots[i]; + int ret; +#ifdef DEBUG_DLINES + grid_edge *e2; + int i2 = i - 1; + if (i2 < 0) i2 += f->order; + e2 = f->edges[i2]; +#endif + ret = 2 * (e - g->edges) + ((e->dot1 == d) ? 1 : 0); +#ifdef DEBUG_DLINES + printf("dline_index_from_face: f=%d,i=%d, edges [%d,%d] - %d\n", + (int)(f - g->faces), i, (int)(e - g->edges), + (int)(e2 - g->edges), ret); +#endif + return ret; +} +static int is_atleastone(const char *dline_array, int index) +{ + return BIT_SET(dline_array[index], 0); +} +static int set_atleastone(char *dline_array, int index) +{ + return SET_BIT(dline_array[index], 0); +} +static int is_atmostone(const char *dline_array, int index) +{ + return BIT_SET(dline_array[index], 1); +} +static int set_atmostone(char *dline_array, int index) +{ + return SET_BIT(dline_array[index], 1); +} + +static void array_setall(char *array, char from, char to, int len) +{ + char *p = array, *p_old = p; + int len_remaining = len; + + while ((p = memchr(p, from, len_remaining))) { + *p = to; + len_remaining -= p - p_old; + p_old = p; + } +} + +/* Helper, called when doing dline dot deductions, in the case where we + * have 4 UNKNOWNs, and two of them (adjacent) have *exactly* one YES between + * them (because of dline atmostone/atleastone). + * On entry, edge points to the first of these two UNKNOWNs. This function + * will find the opposite UNKNOWNS (if they are adjacent to one another) + * and set their corresponding dline to atleastone. (Setting atmostone + * already happens in earlier dline deductions) */ +static int dline_set_opp_atleastone(solver_state *sstate, + grid_dot *d, int edge) +{ + game_state *state = sstate->state; + grid *g = state->game_grid; + int N = d->order; + int opp, opp2; + for (opp = 0; opp < N; opp++) { + int opp_dline_index; + if (opp == edge || opp == edge+1 || opp == edge-1) + continue; + if (opp == 0 && edge == N-1) + continue; + if (opp == N-1 && edge == 0) + continue; + opp2 = opp + 1; + if (opp2 == N) opp2 = 0; + /* Check if opp, opp2 point to LINE_UNKNOWNs */ + if (state->lines[d->edges[opp] - g->edges] != LINE_UNKNOWN) + continue; + if (state->lines[d->edges[opp2] - g->edges] != LINE_UNKNOWN) + continue; + /* Found opposite UNKNOWNS and they're next to each other */ + opp_dline_index = dline_index_from_dot(g, d, opp); + return set_atleastone(sstate->dlines, opp_dline_index); + } + return FALSE; +} + + +/* Set pairs of lines around this face which are known to be identical, to + * the given line_state */ +static int face_setall_identical(solver_state *sstate, int face_index, + enum line_state line_new) +{ + /* can[dir] contains the canonical line associated with the line in + * direction dir from the square in question. Similarly inv[dir] is + * whether or not the line in question is inverse to its canonical + * element. */ + int retval = FALSE; + game_state *state = sstate->state; + grid *g = state->game_grid; + grid_face *f = g->faces + face_index; + int N = f->order; + int i, j; + int can1, can2, inv1, inv2; + + for (i = 0; i < N; i++) { + int line1_index = f->edges[i] - g->edges; + if (state->lines[line1_index] != LINE_UNKNOWN) + continue; + for (j = i + 1; j < N; j++) { + int line2_index = f->edges[j] - g->edges; + if (state->lines[line2_index] != LINE_UNKNOWN) + continue; + + /* Found two UNKNOWNS */ + can1 = edsf_canonify(sstate->linedsf, line1_index, &inv1); + can2 = edsf_canonify(sstate->linedsf, line2_index, &inv2); + if (can1 == can2 && inv1 == inv2) { + solver_set_line(sstate, line1_index, line_new); + solver_set_line(sstate, line2_index, line_new); + } + } + } + return retval; +} + +/* Given a dot or face, and a count of LINE_UNKNOWNs, find them and + * return the edge indices into e. */ +static void find_unknowns(game_state *state, + grid_edge **edge_list, /* Edge list to search (from a face or a dot) */ + int expected_count, /* Number of UNKNOWNs (comes from solver's cache) */ + int *e /* Returned edge indices */) +{ + int c = 0; + grid *g = state->game_grid; + while (c < expected_count) { + int line_index = *edge_list - g->edges; + if (state->lines[line_index] == LINE_UNKNOWN) { + e[c] = line_index; + c++; + } + ++edge_list; + } +} + +/* If we have a list of edges, and we know whether the number of YESs should + * be odd or even, and there are only a few UNKNOWNs, we can do some simple + * linedsf deductions. This can be used for both face and dot deductions. + * Returns the difficulty level of the next solver that should be used, + * or DIFF_MAX if no progress was made. */ +static int parity_deductions(solver_state *sstate, + grid_edge **edge_list, /* Edge list (from a face or a dot) */ + int total_parity, /* Expected number of YESs modulo 2 (either 0 or 1) */ + int unknown_count) +{ + game_state *state = sstate->state; + int diff = DIFF_MAX; + int *linedsf = sstate->linedsf; + + if (unknown_count == 2) { + /* Lines are known alike/opposite, depending on inv. */ + int e[2]; + find_unknowns(state, edge_list, 2, e); + if (merge_lines(sstate, e[0], e[1], total_parity)) + diff = min(diff, DIFF_HARD); + } else if (unknown_count == 3) { + int e[3]; + int can[3]; /* canonical edges */ + int inv[3]; /* whether can[x] is inverse to e[x] */ + find_unknowns(state, edge_list, 3, e); + can[0] = edsf_canonify(linedsf, e[0], inv); + can[1] = edsf_canonify(linedsf, e[1], inv+1); + can[2] = edsf_canonify(linedsf, e[2], inv+2); + if (can[0] == can[1]) { + if (solver_set_line(sstate, e[2], (total_parity^inv[0]^inv[1]) ? + LINE_YES : LINE_NO)) + diff = min(diff, DIFF_EASY); + } + if (can[0] == can[2]) { + if (solver_set_line(sstate, e[1], (total_parity^inv[0]^inv[2]) ? + LINE_YES : LINE_NO)) + diff = min(diff, DIFF_EASY); + } + if (can[1] == can[2]) { + if (solver_set_line(sstate, e[0], (total_parity^inv[1]^inv[2]) ? + LINE_YES : LINE_NO)) + diff = min(diff, DIFF_EASY); + } + } else if (unknown_count == 4) { + int e[4]; + int can[4]; /* canonical edges */ + int inv[4]; /* whether can[x] is inverse to e[x] */ + find_unknowns(state, edge_list, 4, e); + can[0] = edsf_canonify(linedsf, e[0], inv); + can[1] = edsf_canonify(linedsf, e[1], inv+1); + can[2] = edsf_canonify(linedsf, e[2], inv+2); + can[3] = edsf_canonify(linedsf, e[3], inv+3); + if (can[0] == can[1]) { + if (merge_lines(sstate, e[2], e[3], total_parity^inv[0]^inv[1])) + diff = min(diff, DIFF_HARD); + } else if (can[0] == can[2]) { + if (merge_lines(sstate, e[1], e[3], total_parity^inv[0]^inv[2])) + diff = min(diff, DIFF_HARD); + } else if (can[0] == can[3]) { + if (merge_lines(sstate, e[1], e[2], total_parity^inv[0]^inv[3])) + diff = min(diff, DIFF_HARD); + } else if (can[1] == can[2]) { + if (merge_lines(sstate, e[0], e[3], total_parity^inv[1]^inv[2])) + diff = min(diff, DIFF_HARD); + } else if (can[1] == can[3]) { + if (merge_lines(sstate, e[0], e[2], total_parity^inv[1]^inv[3])) + diff = min(diff, DIFF_HARD); + } else if (can[2] == can[3]) { + if (merge_lines(sstate, e[0], e[1], total_parity^inv[2]^inv[3])) + diff = min(diff, DIFF_HARD); + } + } + return diff; +} + + +/* + * These are the main solver functions. + * + * Their return values are diff values corresponding to the lowest mode solver + * that would notice the work that they have done. For example if the normal + * mode solver adds actual lines or crosses, it will return DIFF_EASY as the + * easy mode solver might be able to make progress using that. It doesn't make + * sense for one of them to return a diff value higher than that of the + * function itself. + * + * Each function returns the lowest value it can, as early as possible, in + * order to try and pass as much work as possible back to the lower level + * solvers which progress more quickly. + */ + +/* PROPOSED NEW DESIGN: + * We have a work queue consisting of 'events' notifying us that something has + * happened that a particular solver mode might be interested in. For example + * the hard mode solver might do something that helps the normal mode solver at + * dot [x,y] in which case it will enqueue an event recording this fact. Then + * we pull events off the work queue, and hand each in turn to the solver that + * is interested in them. If a solver reports that it failed we pass the same + * event on to progressively more advanced solvers and the loop detector. Once + * we've exhausted an event, or it has helped us progress, we drop it and + * continue to the next one. The events are sorted first in order of solver + * complexity (easy first) then order of insertion (oldest first). + * Once we run out of events we loop over each permitted solver in turn + * (easiest first) until either a deduction is made (and an event therefore + * emerges) or no further deductions can be made (in which case we've failed). + * + * QUESTIONS: + * * How do we 'loop over' a solver when both dots and squares are concerned. + * Answer: first all squares then all dots. + */ + +static int trivial_deductions(solver_state *sstate) +{ + int i, current_yes, current_no; + game_state *state = sstate->state; + grid *g = state->game_grid; + int diff = DIFF_MAX; + + /* Per-face deductions */ + for (i = 0; i < g->num_faces; i++) { + grid_face *f = g->faces + i; + + if (sstate->face_solved[i]) + continue; + + current_yes = sstate->face_yes_count[i]; + current_no = sstate->face_no_count[i]; + + if (current_yes + current_no == f->order) { + sstate->face_solved[i] = TRUE; + continue; + } + + if (state->clues[i] < 0) + continue; + + /* + * This code checks whether the numeric clue on a face is so + * large as to permit all its remaining LINE_UNKNOWNs to be + * filled in as LINE_YES, or alternatively so small as to + * permit them all to be filled in as LINE_NO. + */ + + if (state->clues[i] < current_yes) { + sstate->solver_status = SOLVER_MISTAKE; + return DIFF_EASY; + } + if (state->clues[i] == current_yes) { + if (face_setall(sstate, i, LINE_UNKNOWN, LINE_NO)) + diff = min(diff, DIFF_EASY); + sstate->face_solved[i] = TRUE; + continue; + } + + if (f->order - state->clues[i] < current_no) { + sstate->solver_status = SOLVER_MISTAKE; + return DIFF_EASY; + } + if (f->order - state->clues[i] == current_no) { + if (face_setall(sstate, i, LINE_UNKNOWN, LINE_YES)) + diff = min(diff, DIFF_EASY); + sstate->face_solved[i] = TRUE; + continue; + } + + if (f->order - state->clues[i] == current_no + 1 && + f->order - current_yes - current_no > 2) { + /* + * One small refinement to the above: we also look for any + * adjacent pair of LINE_UNKNOWNs around the face with + * some LINE_YES incident on it from elsewhere. If we find + * one, then we know that pair of LINE_UNKNOWNs can't + * _both_ be LINE_YES, and hence that pushes us one line + * closer to being able to determine all the rest. + */ + int j, k, e1, e2, e, d; + + for (j = 0; j < f->order; j++) { + e1 = f->edges[j] - g->edges; + e2 = f->edges[j+1 < f->order ? j+1 : 0] - g->edges; + + if (g->edges[e1].dot1 == g->edges[e2].dot1 || + g->edges[e1].dot1 == g->edges[e2].dot2) { + d = g->edges[e1].dot1 - g->dots; + } else { + assert(g->edges[e1].dot2 == g->edges[e2].dot1 || + g->edges[e1].dot2 == g->edges[e2].dot2); + d = g->edges[e1].dot2 - g->dots; + } + + if (state->lines[e1] == LINE_UNKNOWN && + state->lines[e2] == LINE_UNKNOWN) { + for (k = 0; k < g->dots[d].order; k++) { + int e = g->dots[d].edges[k] - g->edges; + if (state->lines[e] == LINE_YES) + goto found; /* multi-level break */ + } + } + } + continue; + + found: + /* + * If we get here, we've found such a pair of edges, and + * they're e1 and e2. + */ + for (j = 0; j < f->order; j++) { + e = f->edges[j] - g->edges; + if (state->lines[e] == LINE_UNKNOWN && e != e1 && e != e2) { + int r = solver_set_line(sstate, e, LINE_YES); + assert(r); + diff = min(diff, DIFF_EASY); + } + } + } + } + + check_caches(sstate); + + /* Per-dot deductions */ + for (i = 0; i < g->num_dots; i++) { + grid_dot *d = g->dots + i; + int yes, no, unknown; + + if (sstate->dot_solved[i]) + continue; + + yes = sstate->dot_yes_count[i]; + no = sstate->dot_no_count[i]; + unknown = d->order - yes - no; + + if (yes == 0) { + if (unknown == 0) { + sstate->dot_solved[i] = TRUE; + } else if (unknown == 1) { + dot_setall(sstate, i, LINE_UNKNOWN, LINE_NO); + diff = min(diff, DIFF_EASY); + sstate->dot_solved[i] = TRUE; + } + } else if (yes == 1) { + if (unknown == 0) { + sstate->solver_status = SOLVER_MISTAKE; + return DIFF_EASY; + } else if (unknown == 1) { + dot_setall(sstate, i, LINE_UNKNOWN, LINE_YES); + diff = min(diff, DIFF_EASY); + } + } else if (yes == 2) { + if (unknown > 0) { + dot_setall(sstate, i, LINE_UNKNOWN, LINE_NO); + diff = min(diff, DIFF_EASY); + } + sstate->dot_solved[i] = TRUE; + } else { + sstate->solver_status = SOLVER_MISTAKE; + return DIFF_EASY; + } + } + + check_caches(sstate); + + return diff; +} + +static int dline_deductions(solver_state *sstate) +{ + game_state *state = sstate->state; + grid *g = state->game_grid; + char *dlines = sstate->dlines; + int i; + int diff = DIFF_MAX; + + /* ------ Face deductions ------ */ + + /* Given a set of dline atmostone/atleastone constraints, need to figure + * out if we can deduce any further info. For more general faces than + * squares, this turns out to be a tricky problem. + * The approach taken here is to define (per face) NxN matrices: + * "maxs" and "mins". + * The entries maxs(j,k) and mins(j,k) define the upper and lower limits + * for the possible number of edges that are YES between positions j and k + * going clockwise around the face. Can think of j and k as marking dots + * around the face (recall the labelling scheme: edge0 joins dot0 to dot1, + * edge1 joins dot1 to dot2 etc). + * Trivially, mins(j,j) = maxs(j,j) = 0, and we don't even bother storing + * these. mins(j,j+1) and maxs(j,j+1) are determined by whether edge{j} + * is YES, NO or UNKNOWN. mins(j,j+2) and maxs(j,j+2) are related to + * the dline atmostone/atleastone status for edges j and j+1. + * + * Then we calculate the remaining entries recursively. We definitely + * know that + * mins(j,k) >= { mins(j,u) + mins(u,k) } for any u between j and k. + * This is because any valid placement of YESs between j and k must give + * a valid placement between j and u, and also between u and k. + * I believe it's sufficient to use just the two values of u: + * j+1 and j+2. Seems to work well in practice - the bounds we compute + * are rigorous, even if they might not be best-possible. + * + * Once we have maxs and mins calculated, we can make inferences about + * each dline{j,j+1} by looking at the possible complementary edge-counts + * mins(j+2,j) and maxs(j+2,j) and comparing these with the face clue. + * As well as dlines, we can make similar inferences about single edges. + * For example, consider a pentagon with clue 3, and we know at most one + * of (edge0, edge1) is YES, and at most one of (edge2, edge3) is YES. + * We could then deduce edge4 is YES, because maxs(0,4) would be 2, so + * that final edge would have to be YES to make the count up to 3. + */ + + /* Much quicker to allocate arrays on the stack than the heap, so + * define the largest possible face size, and base our array allocations + * on that. We check this with an assertion, in case someone decides to + * make a grid which has larger faces than this. Note, this algorithm + * could get quite expensive if there are many large faces. */ +#define MAX_FACE_SIZE 12 + + for (i = 0; i < g->num_faces; i++) { + int maxs[MAX_FACE_SIZE][MAX_FACE_SIZE]; + int mins[MAX_FACE_SIZE][MAX_FACE_SIZE]; + grid_face *f = g->faces + i; + int N = f->order; + int j,m; + int clue = state->clues[i]; + assert(N <= MAX_FACE_SIZE); + if (sstate->face_solved[i]) + continue; + if (clue < 0) continue; + + /* Calculate the (j,j+1) entries */ + for (j = 0; j < N; j++) { + int edge_index = f->edges[j] - g->edges; + int dline_index; + enum line_state line1 = state->lines[edge_index]; + enum line_state line2; + int tmp; + int k = j + 1; + if (k >= N) k = 0; + maxs[j][k] = (line1 == LINE_NO) ? 0 : 1; + mins[j][k] = (line1 == LINE_YES) ? 1 : 0; + /* Calculate the (j,j+2) entries */ + dline_index = dline_index_from_face(g, f, k); + edge_index = f->edges[k] - g->edges; + line2 = state->lines[edge_index]; + k++; + if (k >= N) k = 0; + + /* max */ + tmp = 2; + if (line1 == LINE_NO) tmp--; + if (line2 == LINE_NO) tmp--; + if (tmp == 2 && is_atmostone(dlines, dline_index)) + tmp = 1; + maxs[j][k] = tmp; + + /* min */ + tmp = 0; + if (line1 == LINE_YES) tmp++; + if (line2 == LINE_YES) tmp++; + if (tmp == 0 && is_atleastone(dlines, dline_index)) + tmp = 1; + mins[j][k] = tmp; + } + + /* Calculate the (j,j+m) entries for m between 3 and N-1 */ + for (m = 3; m < N; m++) { + for (j = 0; j < N; j++) { + int k = j + m; + int u = j + 1; + int v = j + 2; + int tmp; + if (k >= N) k -= N; + if (u >= N) u -= N; + if (v >= N) v -= N; + maxs[j][k] = maxs[j][u] + maxs[u][k]; + mins[j][k] = mins[j][u] + mins[u][k]; + tmp = maxs[j][v] + maxs[v][k]; + maxs[j][k] = min(maxs[j][k], tmp); + tmp = mins[j][v] + mins[v][k]; + mins[j][k] = max(mins[j][k], tmp); + } + } + + /* See if we can make any deductions */ + for (j = 0; j < N; j++) { + int k; + grid_edge *e = f->edges[j]; + int line_index = e - g->edges; + int dline_index; + + if (state->lines[line_index] != LINE_UNKNOWN) + continue; + k = j + 1; + if (k >= N) k = 0; + + /* minimum YESs in the complement of this edge */ + if (mins[k][j] > clue) { + sstate->solver_status = SOLVER_MISTAKE; + return DIFF_EASY; + } + if (mins[k][j] == clue) { + /* setting this edge to YES would make at least + * (clue+1) edges - contradiction */ + solver_set_line(sstate, line_index, LINE_NO); + diff = min(diff, DIFF_EASY); + } + if (maxs[k][j] < clue - 1) { + sstate->solver_status = SOLVER_MISTAKE; + return DIFF_EASY; + } + if (maxs[k][j] == clue - 1) { + /* Only way to satisfy the clue is to set edge{j} as YES */ + solver_set_line(sstate, line_index, LINE_YES); + diff = min(diff, DIFF_EASY); + } + + /* More advanced deduction that allows propagation along diagonal + * chains of faces connected by dots, for example, 3-2-...-2-3 + * in square grids. */ + if (sstate->diff >= DIFF_TRICKY) { + /* Now see if we can make dline deduction for edges{j,j+1} */ + e = f->edges[k]; + if (state->lines[e - g->edges] != LINE_UNKNOWN) + /* Only worth doing this for an UNKNOWN,UNKNOWN pair. + * Dlines where one of the edges is known, are handled in the + * dot-deductions */ + continue; + + dline_index = dline_index_from_face(g, f, k); + k++; + if (k >= N) k = 0; + + /* minimum YESs in the complement of this dline */ + if (mins[k][j] > clue - 2) { + /* Adding 2 YESs would break the clue */ + if (set_atmostone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + } + /* maximum YESs in the complement of this dline */ + if (maxs[k][j] < clue) { + /* Adding 2 NOs would mean not enough YESs */ + if (set_atleastone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + } + } + } + } + + if (diff < DIFF_NORMAL) + return diff; + + /* ------ Dot deductions ------ */ + + for (i = 0; i < g->num_dots; i++) { + grid_dot *d = g->dots + i; + int N = d->order; + int yes, no, unknown; + int j; + if (sstate->dot_solved[i]) + continue; + yes = sstate->dot_yes_count[i]; + no = sstate->dot_no_count[i]; + unknown = N - yes - no; + + for (j = 0; j < N; j++) { + int k; + int dline_index; + int line1_index, line2_index; + enum line_state line1, line2; + k = j + 1; + if (k >= N) k = 0; + dline_index = dline_index_from_dot(g, d, j); + line1_index = d->edges[j] - g->edges; + line2_index = d->edges[k] - g->edges; + line1 = state->lines[line1_index]; + line2 = state->lines[line2_index]; + + /* Infer dline state from line state */ + if (line1 == LINE_NO || line2 == LINE_NO) { + if (set_atmostone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + } + if (line1 == LINE_YES || line2 == LINE_YES) { + if (set_atleastone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + } + /* Infer line state from dline state */ + if (is_atmostone(dlines, dline_index)) { + if (line1 == LINE_YES && line2 == LINE_UNKNOWN) { + solver_set_line(sstate, line2_index, LINE_NO); + diff = min(diff, DIFF_EASY); + } + if (line2 == LINE_YES && line1 == LINE_UNKNOWN) { + solver_set_line(sstate, line1_index, LINE_NO); + diff = min(diff, DIFF_EASY); + } + } + if (is_atleastone(dlines, dline_index)) { + if (line1 == LINE_NO && line2 == LINE_UNKNOWN) { + solver_set_line(sstate, line2_index, LINE_YES); + diff = min(diff, DIFF_EASY); + } + if (line2 == LINE_NO && line1 == LINE_UNKNOWN) { + solver_set_line(sstate, line1_index, LINE_YES); + diff = min(diff, DIFF_EASY); + } + } + /* Deductions that depend on the numbers of lines. + * Only bother if both lines are UNKNOWN, otherwise the + * easy-mode solver (or deductions above) would have taken + * care of it. */ + if (line1 != LINE_UNKNOWN || line2 != LINE_UNKNOWN) + continue; + + if (yes == 0 && unknown == 2) { + /* Both these unknowns must be identical. If we know + * atmostone or atleastone, we can make progress. */ + if (is_atmostone(dlines, dline_index)) { + solver_set_line(sstate, line1_index, LINE_NO); + solver_set_line(sstate, line2_index, LINE_NO); + diff = min(diff, DIFF_EASY); + } + if (is_atleastone(dlines, dline_index)) { + solver_set_line(sstate, line1_index, LINE_YES); + solver_set_line(sstate, line2_index, LINE_YES); + diff = min(diff, DIFF_EASY); + } + } + if (yes == 1) { + if (set_atmostone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + if (unknown == 2) { + if (set_atleastone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + } + } + + /* More advanced deduction that allows propagation along diagonal + * chains of faces connected by dots, for example: 3-2-...-2-3 + * in square grids. */ + if (sstate->diff >= DIFF_TRICKY) { + /* If we have atleastone set for this dline, infer + * atmostone for each "opposite" dline (that is, each + * dline without edges in common with this one). + * Again, this test is only worth doing if both these + * lines are UNKNOWN. For if one of these lines were YES, + * the (yes == 1) test above would kick in instead. */ + if (is_atleastone(dlines, dline_index)) { + int opp; + for (opp = 0; opp < N; opp++) { + int opp_dline_index; + if (opp == j || opp == j+1 || opp == j-1) + continue; + if (j == 0 && opp == N-1) + continue; + if (j == N-1 && opp == 0) + continue; + opp_dline_index = dline_index_from_dot(g, d, opp); + if (set_atmostone(dlines, opp_dline_index)) + diff = min(diff, DIFF_NORMAL); + } + if (yes == 0 && is_atmostone(dlines, dline_index)) { + /* This dline has *exactly* one YES and there are no + * other YESs. This allows more deductions. */ + if (unknown == 3) { + /* Third unknown must be YES */ + for (opp = 0; opp < N; opp++) { + int opp_index; + if (opp == j || opp == k) + continue; + opp_index = d->edges[opp] - g->edges; + if (state->lines[opp_index] == LINE_UNKNOWN) { + solver_set_line(sstate, opp_index, + LINE_YES); + diff = min(diff, DIFF_EASY); + } + } + } else if (unknown == 4) { + /* Exactly one of opposite UNKNOWNS is YES. We've + * already set atmostone, so set atleastone as + * well. + */ + if (dline_set_opp_atleastone(sstate, d, j)) + diff = min(diff, DIFF_NORMAL); + } + } + } + } + } + } + return diff; +} + +static int linedsf_deductions(solver_state *sstate) +{ + game_state *state = sstate->state; + grid *g = state->game_grid; + char *dlines = sstate->dlines; + int i; + int diff = DIFF_MAX; + int diff_tmp; + + /* ------ Face deductions ------ */ + + /* A fully-general linedsf deduction seems overly complicated + * (I suspect the problem is NP-complete, though in practice it might just + * be doable because faces are limited in size). + * For simplicity, we only consider *pairs* of LINE_UNKNOWNS that are + * known to be identical. If setting them both to YES (or NO) would break + * the clue, set them to NO (or YES). */ + + for (i = 0; i < g->num_faces; i++) { + int N, yes, no, unknown; + int clue; + + if (sstate->face_solved[i]) + continue; + clue = state->clues[i]; + if (clue < 0) + continue; + + N = g->faces[i].order; + yes = sstate->face_yes_count[i]; + if (yes + 1 == clue) { + if (face_setall_identical(sstate, i, LINE_NO)) + diff = min(diff, DIFF_EASY); + } + no = sstate->face_no_count[i]; + if (no + 1 == N - clue) { + if (face_setall_identical(sstate, i, LINE_YES)) + diff = min(diff, DIFF_EASY); + } + + /* Reload YES count, it might have changed */ + yes = sstate->face_yes_count[i]; + unknown = N - no - yes; + + /* Deductions with small number of LINE_UNKNOWNs, based on overall + * parity of lines. */ + diff_tmp = parity_deductions(sstate, g->faces[i].edges, + (clue - yes) % 2, unknown); + diff = min(diff, diff_tmp); + } + + /* ------ Dot deductions ------ */ + for (i = 0; i < g->num_dots; i++) { + grid_dot *d = g->dots + i; + int N = d->order; + int j; + int yes, no, unknown; + /* Go through dlines, and do any dline<->linedsf deductions wherever + * we find two UNKNOWNS. */ + for (j = 0; j < N; j++) { + int dline_index = dline_index_from_dot(g, d, j); + int line1_index; + int line2_index; + int can1, can2, inv1, inv2; + int j2; + line1_index = d->edges[j] - g->edges; + if (state->lines[line1_index] != LINE_UNKNOWN) + continue; + j2 = j + 1; + if (j2 == N) j2 = 0; + line2_index = d->edges[j2] - g->edges; + if (state->lines[line2_index] != LINE_UNKNOWN) + continue; + /* Infer dline flags from linedsf */ + can1 = edsf_canonify(sstate->linedsf, line1_index, &inv1); + can2 = edsf_canonify(sstate->linedsf, line2_index, &inv2); + if (can1 == can2 && inv1 != inv2) { + /* These are opposites, so set dline atmostone/atleastone */ + if (set_atmostone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + if (set_atleastone(dlines, dline_index)) + diff = min(diff, DIFF_NORMAL); + continue; + } + /* Infer linedsf from dline flags */ + if (is_atmostone(dlines, dline_index) + && is_atleastone(dlines, dline_index)) { + if (merge_lines(sstate, line1_index, line2_index, 1)) + diff = min(diff, DIFF_HARD); + } + } + + /* Deductions with small number of LINE_UNKNOWNs, based on overall + * parity of lines. */ + yes = sstate->dot_yes_count[i]; + no = sstate->dot_no_count[i]; + unknown = N - yes - no; + diff_tmp = parity_deductions(sstate, d->edges, + yes % 2, unknown); + diff = min(diff, diff_tmp); + } + + /* ------ Edge dsf deductions ------ */ + + /* If the state of a line is known, deduce the state of its canonical line + * too, and vice versa. */ + for (i = 0; i < g->num_edges; i++) { + int can, inv; + enum line_state s; + can = edsf_canonify(sstate->linedsf, i, &inv); + if (can == i) + continue; + s = sstate->state->lines[can]; + if (s != LINE_UNKNOWN) { + if (solver_set_line(sstate, i, inv ? OPP(s) : s)) + diff = min(diff, DIFF_EASY); + } else { + s = sstate->state->lines[i]; + if (s != LINE_UNKNOWN) { + if (solver_set_line(sstate, can, inv ? OPP(s) : s)) + diff = min(diff, DIFF_EASY); + } + } + } + + return diff; +} + +static int loop_deductions(solver_state *sstate) +{ + int edgecount = 0, clues = 0, satclues = 0, sm1clues = 0; + game_state *state = sstate->state; + grid *g = state->game_grid; + int shortest_chainlen = g->num_dots; + int loop_found = FALSE; + int dots_connected; + int progress = FALSE; + int i; + + /* + * Go through the grid and update for all the new edges. + * Since merge_dots() is idempotent, the simplest way to + * do this is just to update for _all_ the edges. + * Also, while we're here, we count the edges. + */ + for (i = 0; i < g->num_edges; i++) { + if (state->lines[i] == LINE_YES) { + loop_found |= merge_dots(sstate, i); + edgecount++; + } + } + + /* + * Count the clues, count the satisfied clues, and count the + * satisfied-minus-one clues. + */ + for (i = 0; i < g->num_faces; i++) { + int c = state->clues[i]; + if (c >= 0) { + int o = sstate->face_yes_count[i]; + if (o == c) + satclues++; + else if (o == c-1) + sm1clues++; + clues++; + } + } + + for (i = 0; i < g->num_dots; ++i) { + dots_connected = + sstate->looplen[dsf_canonify(sstate->dotdsf, i)]; + if (dots_connected > 1) + shortest_chainlen = min(shortest_chainlen, dots_connected); + } + + assert(sstate->solver_status == SOLVER_INCOMPLETE); + + if (satclues == clues && shortest_chainlen == edgecount) { + sstate->solver_status = SOLVER_SOLVED; + /* This discovery clearly counts as progress, even if we haven't + * just added any lines or anything */ + progress = TRUE; + goto finished_loop_deductionsing; + } + + /* + * Now go through looking for LINE_UNKNOWN edges which + * connect two dots that are already in the same + * equivalence class. If we find one, test to see if the + * loop it would create is a solution. + */ + for (i = 0; i < g->num_edges; i++) { + grid_edge *e = g->edges + i; + int d1 = e->dot1 - g->dots; + int d2 = e->dot2 - g->dots; + int eqclass, val; + if (state->lines[i] != LINE_UNKNOWN) + continue; + + eqclass = dsf_canonify(sstate->dotdsf, d1); + if (eqclass != dsf_canonify(sstate->dotdsf, d2)) + continue; + + val = LINE_NO; /* loop is bad until proven otherwise */ + + /* + * This edge would form a loop. Next + * question: how long would the loop be? + * Would it equal the total number of edges + * (plus the one we'd be adding if we added + * it)? + */ + if (sstate->looplen[eqclass] == edgecount + 1) { + int sm1_nearby; + + /* + * This edge would form a loop which + * took in all the edges in the entire + * grid. So now we need to work out + * whether it would be a valid solution + * to the puzzle, which means we have to + * check if it satisfies all the clues. + * This means that every clue must be + * either satisfied or satisfied-minus- + * 1, and also that the number of + * satisfied-minus-1 clues must be at + * most two and they must lie on either + * side of this edge. + */ + sm1_nearby = 0; + if (e->face1) { + int f = e->face1 - g->faces; + int c = state->clues[f]; + if (c >= 0 && sstate->face_yes_count[f] == c - 1) + sm1_nearby++; + } + if (e->face2) { + int f = e->face2 - g->faces; + int c = state->clues[f]; + if (c >= 0 && sstate->face_yes_count[f] == c - 1) + sm1_nearby++; + } + if (sm1clues == sm1_nearby && + sm1clues + satclues == clues) { + val = LINE_YES; /* loop is good! */ + } + } + + /* + * Right. Now we know that adding this edge + * would form a loop, and we know whether + * that loop would be a viable solution or + * not. + * + * If adding this edge produces a solution, + * then we know we've found _a_ solution but + * we don't know that it's _the_ solution - + * if it were provably the solution then + * we'd have deduced this edge some time ago + * without the need to do loop detection. So + * in this state we return SOLVER_AMBIGUOUS, + * which has the effect that hitting Solve + * on a user-provided puzzle will fill in a + * solution but using the solver to + * construct new puzzles won't consider this + * a reasonable deduction for the user to + * make. + */ + progress = solver_set_line(sstate, i, val); + assert(progress == TRUE); + if (val == LINE_YES) { + sstate->solver_status = SOLVER_AMBIGUOUS; + goto finished_loop_deductionsing; + } + } + + finished_loop_deductionsing: + return progress ? DIFF_EASY : DIFF_MAX; +} + +/* This will return a dynamically allocated solver_state containing the (more) + * solved grid */ +static solver_state *solve_game_rec(const solver_state *sstate_start) +{ + solver_state *sstate; + + /* Index of the solver we should call next. */ + int i = 0; + + /* As a speed-optimisation, we avoid re-running solvers that we know + * won't make any progress. This happens when a high-difficulty + * solver makes a deduction that can only help other high-difficulty + * solvers. + * For example: if a new 'dline' flag is set by dline_deductions, the + * trivial_deductions solver cannot do anything with this information. + * If we've already run the trivial_deductions solver (because it's + * earlier in the list), there's no point running it again. + * + * Therefore: if a solver is earlier in the list than "threshold_index", + * we don't bother running it if it's difficulty level is less than + * "threshold_diff". + */ + int threshold_diff = 0; + int threshold_index = 0; + + sstate = dup_solver_state(sstate_start); + + check_caches(sstate); + + while (i < NUM_SOLVERS) { + if (sstate->solver_status == SOLVER_MISTAKE) + return sstate; + if (sstate->solver_status == SOLVER_SOLVED || + sstate->solver_status == SOLVER_AMBIGUOUS) { + /* solver finished */ + break; + } + + if ((solver_diffs[i] >= threshold_diff || i >= threshold_index) + && solver_diffs[i] <= sstate->diff) { + /* current_solver is eligible, so use it */ + int next_diff = solver_fns[i](sstate); + if (next_diff != DIFF_MAX) { + /* solver made progress, so use new thresholds and + * start again at top of list. */ + threshold_diff = next_diff; + threshold_index = i; + i = 0; + continue; + } + } + /* current_solver is ineligible, or failed to make progress, so + * go to the next solver in the list */ + i++; + } + + if (sstate->solver_status == SOLVER_SOLVED || + sstate->solver_status == SOLVER_AMBIGUOUS) { + /* s/LINE_UNKNOWN/LINE_NO/g */ + array_setall(sstate->state->lines, LINE_UNKNOWN, LINE_NO, + sstate->state->game_grid->num_edges); + return sstate; + } + + return sstate; +} + +static char *solve_game(const game_state *state, const game_state *currstate, + const char *aux, char **error) +{ + char *soln = NULL; + solver_state *sstate, *new_sstate; + + sstate = new_solver_state(state, DIFF_MAX); + new_sstate = solve_game_rec(sstate); + + if (new_sstate->solver_status == SOLVER_SOLVED) { + soln = encode_solve_move(new_sstate->state); + } else if (new_sstate->solver_status == SOLVER_AMBIGUOUS) { + soln = encode_solve_move(new_sstate->state); + /**error = "Solver found ambiguous solutions"; */ + } else { + soln = encode_solve_move(new_sstate->state); + /**error = "Solver failed"; */ + } + + free_solver_state(new_sstate); + free_solver_state(sstate); + + return soln; +} + +/* ---------------------------------------------------------------------- + * Drawing and mouse-handling + */ + +static char *interpret_move(const game_state *state, game_ui *ui, + const game_drawstate *ds, + int x, int y, int button) +{ + grid *g = state->game_grid; + grid_edge *e; + int i; + char *ret, buf[80]; + char button_char = ' '; + enum line_state old_state; + + button &= ~MOD_MASK; + + /* Convert mouse-click (x,y) to grid coordinates */ + x -= BORDER(ds->tilesize); + y -= BORDER(ds->tilesize); + x = x * g->tilesize / ds->tilesize; + y = y * g->tilesize / ds->tilesize; + x += g->lowest_x; + y += g->lowest_y; + + e = grid_nearest_edge(g, x, y); + if (e == NULL) + return NULL; + + i = e - g->edges; + + /* I think it's only possible to play this game with mouse clicks, sorry */ + /* Maybe will add mouse drag support some time */ + old_state = state->lines[i]; + + switch (button) { + case LEFT_BUTTON: + switch (old_state) { + case LINE_UNKNOWN: + button_char = 'y'; + break; + case LINE_YES: +#ifdef STYLUS_BASED + button_char = 'n'; + break; +#endif + case LINE_NO: + button_char = 'u'; + break; + } + break; + case MIDDLE_BUTTON: + button_char = 'u'; + break; + case RIGHT_BUTTON: + switch (old_state) { + case LINE_UNKNOWN: + button_char = 'n'; + break; + case LINE_NO: +#ifdef STYLUS_BASED + button_char = 'y'; + break; +#endif + case LINE_YES: + button_char = 'u'; + break; + } + break; + default: + return NULL; + } + + + sprintf(buf, "%d%c", i, (int)button_char); + ret = dupstr(buf); + + return ret; +} + +static game_state *execute_move(const game_state *state, const char *move) +{ + int i; + game_state *newstate = dup_game(state); + + if (move[0] == 'S') { + move++; + newstate->cheated = TRUE; + } + + while (*move) { + i = atoi(move); + if (i < 0 || i >= newstate->game_grid->num_edges) + goto fail; + move += strspn(move, "1234567890"); + switch (*(move++)) { + case 'y': + newstate->lines[i] = LINE_YES; + break; + case 'n': + newstate->lines[i] = LINE_NO; + break; + case 'u': + newstate->lines[i] = LINE_UNKNOWN; + break; + default: + goto fail; + } + } + + /* + * Check for completion. + */ + if (check_completion(newstate)) + newstate->solved = TRUE; + + return newstate; + + fail: + free_game(newstate); + return NULL; +} + +/* ---------------------------------------------------------------------- + * Drawing routines. + */ + +/* Convert from grid coordinates to screen coordinates */ +static void grid_to_screen(const game_drawstate *ds, const grid *g, + int grid_x, int grid_y, int *x, int *y) +{ + *x = grid_x - g->lowest_x; + *y = grid_y - g->lowest_y; + *x = *x * ds->tilesize / g->tilesize; + *y = *y * ds->tilesize / g->tilesize; + *x += BORDER(ds->tilesize); + *y += BORDER(ds->tilesize); +} + +/* Returns (into x,y) position of centre of face for rendering the text clue. + */ +static void face_text_pos(const game_drawstate *ds, const grid *g, + grid_face *f, int *xret, int *yret) +{ + int faceindex = f - g->faces; + + /* + * Return the cached position for this face, if we've already + * worked it out. + */ + if (ds->textx[faceindex] >= 0) { + *xret = ds->textx[faceindex]; + *yret = ds->texty[faceindex]; + return; + } + + /* + * Otherwise, use the incentre computed by grid.c and convert it + * to screen coordinates. + */ + grid_find_incentre(f); + grid_to_screen(ds, g, f->ix, f->iy, + &ds->textx[faceindex], &ds->texty[faceindex]); + + *xret = ds->textx[faceindex]; + *yret = ds->texty[faceindex]; +} + +static void face_text_bbox(game_drawstate *ds, grid *g, grid_face *f, + int *x, int *y, int *w, int *h) +{ + int xx, yy; + face_text_pos(ds, g, f, &xx, &yy); + + /* There seems to be a certain amount of trial-and-error involved + * in working out the correct bounding-box for the text. */ + + *x = xx - ds->tilesize/4 - 1; + *y = yy - ds->tilesize/4 - 3; + *w = ds->tilesize/2 + 2; + *h = ds->tilesize/2 + 5; +} + +static void game_redraw_clue(drawing *dr, game_drawstate *ds, + const game_state *state, int i) +{ + grid *g = state->game_grid; + grid_face *f = g->faces + i; + int x, y; + char c[20]; + + sprintf(c, "%d", state->clues[i]); + + face_text_pos(ds, g, f, &x, &y); + draw_text(dr, x, y, + FONT_VARIABLE, ds->tilesize/2, + ALIGN_VCENTRE | ALIGN_HCENTRE, + ds->clue_error[i] ? COL_MISTAKE : + ds->clue_satisfied[i] ? COL_SATISFIED : COL_FOREGROUND, c); +} + +static void edge_bbox(game_drawstate *ds, grid *g, grid_edge *e, + int *x, int *y, int *w, int *h) +{ + int x1 = e->dot1->x; + int y1 = e->dot1->y; + int x2 = e->dot2->x; + int y2 = e->dot2->y; + int xmin, xmax, ymin, ymax; + + grid_to_screen(ds, g, x1, y1, &x1, &y1); + grid_to_screen(ds, g, x2, y2, &x2, &y2); + /* Allow extra margin for dots, and thickness of lines */ + xmin = min(x1, x2) - 2; + xmax = max(x1, x2) + 2; + ymin = min(y1, y2) - 2; + ymax = max(y1, y2) + 2; + + *x = xmin; + *y = ymin; + *w = xmax - xmin + 1; + *h = ymax - ymin + 1; +} + +static void dot_bbox(game_drawstate *ds, grid *g, grid_dot *d, + int *x, int *y, int *w, int *h) +{ + int x1, y1; + + grid_to_screen(ds, g, d->x, d->y, &x1, &y1); + + *x = x1 - 2; + *y = y1 - 2; + *w = 5; + *h = 5; +} + +static const int loopy_line_redraw_phases[] = { + COL_FAINT, COL_LINEUNKNOWN, COL_FOREGROUND, COL_HIGHLIGHT, COL_MISTAKE +}; +#define NPHASES lenof(loopy_line_redraw_phases) + +static void game_redraw_line(drawing *dr, game_drawstate *ds, + const game_state *state, int i, int phase) +{ + grid *g = state->game_grid; + grid_edge *e = g->edges + i; + int x1, x2, y1, y2; + int line_colour; + + if (state->line_errors[i]) + line_colour = COL_MISTAKE; + else if (state->lines[i] == LINE_UNKNOWN) + line_colour = COL_LINEUNKNOWN; + else if (state->lines[i] == LINE_NO) + line_colour = COL_FAINT; + else if (ds->flashing) + line_colour = COL_HIGHLIGHT; + else + line_colour = COL_FOREGROUND; + if (line_colour != loopy_line_redraw_phases[phase]) + return; + + /* Convert from grid to screen coordinates */ + grid_to_screen(ds, g, e->dot1->x, e->dot1->y, &x1, &y1); + grid_to_screen(ds, g, e->dot2->x, e->dot2->y, &x2, &y2); + + if (line_colour == COL_FAINT) { + static int draw_faint_lines = -1; + if (draw_faint_lines < 0) { + char *env = getenv("LOOPY_FAINT_LINES"); + draw_faint_lines = (!env || (env[0] == 'y' || + env[0] == 'Y')); + } + if (draw_faint_lines) + draw_line(dr, x1, y1, x2, y2, line_colour); + } else { + draw_thick_line(dr, 3.0, + x1 + 0.5, y1 + 0.5, + x2 + 0.5, y2 + 0.5, + line_colour); + } +} + +static void game_redraw_dot(drawing *dr, game_drawstate *ds, + const game_state *state, int i) +{ + grid *g = state->game_grid; + grid_dot *d = g->dots + i; + int x, y; + + grid_to_screen(ds, g, d->x, d->y, &x, &y); + draw_circle(dr, x, y, 2, COL_FOREGROUND, COL_FOREGROUND); +} + +static int boxes_intersect(int x0, int y0, int w0, int h0, + int x1, int y1, int w1, int h1) +{ + /* + * Two intervals intersect iff neither is wholly on one side of + * the other. Two boxes intersect iff their horizontal and + * vertical intervals both intersect. + */ + return (x0 < x1+w1 && x1 < x0+w0 && y0 < y1+h1 && y1 < y0+h0); +} + +static void game_redraw_in_rect(drawing *dr, game_drawstate *ds, + const game_state *state, + int x, int y, int w, int h) +{ + grid *g = state->game_grid; + int i, phase; + int bx, by, bw, bh; + + clip(dr, x, y, w, h); + draw_rect(dr, x, y, w, h, COL_BACKGROUND); + + for (i = 0; i < g->num_faces; i++) { + if (state->clues[i] >= 0) { + face_text_bbox(ds, g, &g->faces[i], &bx, &by, &bw, &bh); + if (boxes_intersect(x, y, w, h, bx, by, bw, bh)) + game_redraw_clue(dr, ds, state, i); + } + } + for (phase = 0; phase < NPHASES; phase++) { + for (i = 0; i < g->num_edges; i++) { + edge_bbox(ds, g, &g->edges[i], &bx, &by, &bw, &bh); + if (boxes_intersect(x, y, w, h, bx, by, bw, bh)) + game_redraw_line(dr, ds, state, i, phase); + } + } + for (i = 0; i < g->num_dots; i++) { + dot_bbox(ds, g, &g->dots[i], &bx, &by, &bw, &bh); + if (boxes_intersect(x, y, w, h, bx, by, bw, bh)) + game_redraw_dot(dr, ds, state, i); + } + + unclip(dr); + draw_update(dr, x, y, w, h); +} + +static void game_redraw(drawing *dr, game_drawstate *ds, + const game_state *oldstate, const game_state *state, + int dir, const game_ui *ui, + float animtime, float flashtime) +{ +#define REDRAW_OBJECTS_LIMIT 16 /* Somewhat arbitrary tradeoff */ + + grid *g = state->game_grid; + int border = BORDER(ds->tilesize); + int i; + int flash_changed; + int redraw_everything = FALSE; + + int edges[REDRAW_OBJECTS_LIMIT], nedges = 0; + int faces[REDRAW_OBJECTS_LIMIT], nfaces = 0; + + /* Redrawing is somewhat involved. + * + * An update can theoretically affect an arbitrary number of edges + * (consider, for example, completing or breaking a cycle which doesn't + * satisfy all the clues -- we'll switch many edges between error and + * normal states). On the other hand, redrawing the whole grid takes a + * while, making the game feel sluggish, and many updates are actually + * quite well localized. + * + * This redraw algorithm attempts to cope with both situations gracefully + * and correctly. For localized changes, we set a clip rectangle, fill + * it with background, and then redraw (a plausible but conservative + * guess at) the objects which intersect the rectangle; if several + * objects need redrawing, we'll do them individually. However, if lots + * of objects are affected, we'll just redraw everything. + * + * The reason for all of this is that it's just not safe to do the redraw + * piecemeal. If you try to draw an antialiased diagonal line over + * itself, you get a slightly thicker antialiased diagonal line, which + * looks rather ugly after a while. + * + * So, we take two passes over the grid. The first attempts to work out + * what needs doing, and the second actually does it. + */ + + if (!ds->started) { + redraw_everything = TRUE; + /* + * But we must still go through the upcoming loops, so that we + * set up stuff in ds correctly for the initial redraw. + */ + } + + /* First, trundle through the faces. */ + for (i = 0; i < g->num_faces; i++) { + grid_face *f = g->faces + i; + int sides = f->order; + int yes_order, no_order; + int clue_mistake; + int clue_satisfied; + int n = state->clues[i]; + if (n < 0) + continue; + + yes_order = face_order(state, i, LINE_YES); + if (state->exactly_one_loop) { + /* + * Special case: if the set of LINE_YES edges in the grid + * consists of exactly one loop and nothing else, then we + * switch to treating LINE_UNKNOWN the same as LINE_NO for + * purposes of clue checking. + * + * This is because some people like to play Loopy without + * using the right-click, i.e. never setting anything to + * LINE_NO. Without this special case, if a person playing + * in that style fills in what they think is a correct + * solution loop but in fact it has an underfilled clue, + * then we will display no victory flash and also no error + * highlight explaining why not. With this special case, + * we light up underfilled clues at the instant the loop + * is closed. (Of course, *overfilled* clues are fine + * either way.) + * + * (It might still be considered unfortunate that we can't + * warn this style of player any earlier, if they make a + * mistake very near the beginning which doesn't show up + * until they close the last edge of the loop. One other + * thing we _could_ do here is to treat any LINE_UNKNOWN + * as LINE_NO if either of its endpoints has yes-degree 2, + * reflecting the fact that setting that line to YES would + * be an obvious error. But I don't think even that could + * catch _all_ clue errors in a timely manner; I think + * there are some that won't be displayed until the loop + * is filled in, even so, and there's no way to avoid that + * with complete reliability except to switch to being a + * player who sets things to LINE_NO.) + */ + no_order = sides - yes_order; + } else { + no_order = face_order(state, i, LINE_NO); + } + + clue_mistake = (yes_order > n || no_order > (sides-n)); + clue_satisfied = (yes_order == n && no_order == (sides-n)); + + if (clue_mistake != ds->clue_error[i] || + clue_satisfied != ds->clue_satisfied[i]) { + ds->clue_error[i] = clue_mistake; + ds->clue_satisfied[i] = clue_satisfied; + if (nfaces == REDRAW_OBJECTS_LIMIT) + redraw_everything = TRUE; + else + faces[nfaces++] = i; + } + } + + /* Work out what the flash state needs to be. */ + if (flashtime > 0 && + (flashtime <= FLASH_TIME/3 || + flashtime >= FLASH_TIME*2/3)) { + flash_changed = !ds->flashing; + ds->flashing = TRUE; + } else { + flash_changed = ds->flashing; + ds->flashing = FALSE; + } + + /* Now, trundle through the edges. */ + for (i = 0; i < g->num_edges; i++) { + char new_ds = + state->line_errors[i] ? DS_LINE_ERROR : state->lines[i]; + if (new_ds != ds->lines[i] || + (flash_changed && state->lines[i] == LINE_YES)) { + ds->lines[i] = new_ds; + if (nedges == REDRAW_OBJECTS_LIMIT) + redraw_everything = TRUE; + else + edges[nedges++] = i; + } + } + + /* Pass one is now done. Now we do the actual drawing. */ + if (redraw_everything) { + int grid_width = g->highest_x - g->lowest_x; + int grid_height = g->highest_y - g->lowest_y; + int w = grid_width * ds->tilesize / g->tilesize; + int h = grid_height * ds->tilesize / g->tilesize; + + game_redraw_in_rect(dr, ds, state, + 0, 0, w + 2*border + 1, h + 2*border + 1); + } else { + + /* Right. Now we roll up our sleeves. */ + + for (i = 0; i < nfaces; i++) { + grid_face *f = g->faces + faces[i]; + int x, y, w, h; + + face_text_bbox(ds, g, f, &x, &y, &w, &h); + game_redraw_in_rect(dr, ds, state, x, y, w, h); + } + + for (i = 0; i < nedges; i++) { + grid_edge *e = g->edges + edges[i]; + int x, y, w, h; + + edge_bbox(ds, g, e, &x, &y, &w, &h); + game_redraw_in_rect(dr, ds, state, x, y, w, h); + } + } + + ds->started = TRUE; +} + +static float game_flash_length(const game_state *oldstate, + const game_state *newstate, int dir, game_ui *ui) +{ + if (!oldstate->solved && newstate->solved && + !oldstate->cheated && !newstate->cheated) { + return FLASH_TIME; + } + + return 0.0F; +} + +static int game_status(const game_state *state) +{ + return state->solved ? +1 : 0; +} + +static void game_print_size(const game_params *params, float *x, float *y) +{ + int pw, ph; + + /* + * I'll use 7mm "squares" by default. + */ + game_compute_size(params, 700, &pw, &ph); + *x = pw / 100.0F; + *y = ph / 100.0F; +} + +static void game_print(drawing *dr, const game_state *state, int tilesize) +{ + int ink = print_mono_colour(dr, 0); + int i; + game_drawstate ads, *ds = &ads; + grid *g = state->game_grid; + + ds->tilesize = tilesize; + ds->textx = snewn(g->num_faces, int); + ds->texty = snewn(g->num_faces, int); + for (i = 0; i < g->num_faces; i++) + ds->textx[i] = ds->texty[i] = -1; + + for (i = 0; i < g->num_dots; i++) { + int x, y; + grid_to_screen(ds, g, g->dots[i].x, g->dots[i].y, &x, &y); + draw_circle(dr, x, y, ds->tilesize / 15, ink, ink); + } + + /* + * Clues. + */ + for (i = 0; i < g->num_faces; i++) { + grid_face *f = g->faces + i; + int clue = state->clues[i]; + if (clue >= 0) { + char c[20]; + int x, y; + sprintf(c, "%d", state->clues[i]); + face_text_pos(ds, g, f, &x, &y); + draw_text(dr, x, y, + FONT_VARIABLE, ds->tilesize / 2, + ALIGN_VCENTRE | ALIGN_HCENTRE, ink, c); + } + } + + /* + * Lines. + */ + for (i = 0; i < g->num_edges; i++) { + int thickness = (state->lines[i] == LINE_YES) ? 30 : 150; + grid_edge *e = g->edges + i; + int x1, y1, x2, y2; + grid_to_screen(ds, g, e->dot1->x, e->dot1->y, &x1, &y1); + grid_to_screen(ds, g, e->dot2->x, e->dot2->y, &x2, &y2); + if (state->lines[i] == LINE_YES) + { + /* (dx, dy) points from (x1, y1) to (x2, y2). + * The line is then "fattened" in a perpendicular + * direction to create a thin rectangle. */ + double d = sqrt(SQ((double)x1 - x2) + SQ((double)y1 - y2)); + double dx = (x2 - x1) / d; + double dy = (y2 - y1) / d; + int points[8]; + + dx = (dx * ds->tilesize) / thickness; + dy = (dy * ds->tilesize) / thickness; + points[0] = x1 + (int)dy; + points[1] = y1 - (int)dx; + points[2] = x1 - (int)dy; + points[3] = y1 + (int)dx; + points[4] = x2 - (int)dy; + points[5] = y2 + (int)dx; + points[6] = x2 + (int)dy; + points[7] = y2 - (int)dx; + draw_polygon(dr, points, 4, ink, ink); + } + else + { + /* Draw a dotted line */ + int divisions = 6; + int j; + for (j = 1; j < divisions; j++) { + /* Weighted average */ + int x = (x1 * (divisions -j) + x2 * j) / divisions; + int y = (y1 * (divisions -j) + y2 * j) / divisions; + draw_circle(dr, x, y, ds->tilesize / thickness, ink, ink); + } + } + } + + sfree(ds->textx); + sfree(ds->texty); +} + +#ifdef COMBINED +#define thegame loopy +#endif + +const struct game thegame = { + "Loopy", "games.loopy", "loopy", + default_params, + game_fetch_preset, + decode_params, + encode_params, + free_params, + dup_params, + TRUE, game_configure, custom_params, + validate_params, + new_game_desc, + validate_desc, + new_game, + dup_game, + free_game, + 1, solve_game, + TRUE, game_can_format_as_text_now, game_text_format, + new_ui, + free_ui, + 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_status, + TRUE, FALSE, game_print_size, game_print, + FALSE /* wants_statusbar */, + FALSE, game_timing_state, + 0, /* mouse_priorities */ +}; + +#ifdef STANDALONE_SOLVER + +/* + * Half-hearted standalone solver. It can't output the solution to + * anything but a square puzzle, and it can't log the deductions + * it makes either. But it can solve square puzzles, and more + * importantly it can use its solver to grade the difficulty of + * any puzzle you give it. + */ + +#include <stdarg.h> + +int main(int argc, char **argv) +{ + game_params *p; + game_state *s; + char *id = NULL, *desc, *err; + int grade = FALSE; + int ret, diff; +#if 0 /* verbose solver not supported here (yet) */ + int really_verbose = FALSE; +#endif + + while (--argc > 0) { + char *p = *++argv; +#if 0 /* verbose solver not supported here (yet) */ + if (!strcmp(p, "-v")) { + really_verbose = TRUE; + } else +#endif + if (!strcmp(p, "-g")) { + grade = TRUE; + } else if (*p == '-') { + fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p); + return 1; + } else { + id = p; + } + } + + if (!id) { + fprintf(stderr, "usage: %s [-g | -v] <game_id>\n", argv[0]); + return 1; + } + + desc = strchr(id, ':'); + if (!desc) { + fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]); + return 1; + } + *desc++ = '\0'; + + p = default_params(); + decode_params(p, id); + err = validate_desc(p, desc); + if (err) { + fprintf(stderr, "%s: %s\n", argv[0], err); + return 1; + } + s = new_game(NULL, p, desc); + + /* + * When solving an Easy puzzle, we don't want to bother the + * user with Hard-level deductions. For this reason, we grade + * the puzzle internally before doing anything else. + */ + ret = -1; /* placate optimiser */ + for (diff = 0; diff < DIFF_MAX; diff++) { + solver_state *sstate_new; + solver_state *sstate = new_solver_state((game_state *)s, diff); + + sstate_new = solve_game_rec(sstate); + + if (sstate_new->solver_status == SOLVER_MISTAKE) + ret = 0; + else if (sstate_new->solver_status == SOLVER_SOLVED) + ret = 1; + else + ret = 2; + + free_solver_state(sstate_new); + free_solver_state(sstate); + + if (ret < 2) + break; + } + + if (diff == DIFF_MAX) { + if (grade) + printf("Difficulty rating: harder than Hard, or ambiguous\n"); + else + printf("Unable to find a unique solution\n"); + } else { + if (grade) { + if (ret == 0) + printf("Difficulty rating: impossible (no solution exists)\n"); + else if (ret == 1) + printf("Difficulty rating: %s\n", diffnames[diff]); + } else { + solver_state *sstate_new; + solver_state *sstate = new_solver_state((game_state *)s, diff); + + /* If we supported a verbose solver, we'd set verbosity here */ + + sstate_new = solve_game_rec(sstate); + + if (sstate_new->solver_status == SOLVER_MISTAKE) + printf("Puzzle is inconsistent\n"); + else { + assert(sstate_new->solver_status == SOLVER_SOLVED); + if (s->grid_type == 0) { + fputs(game_text_format(sstate_new->state), stdout); + } else { + printf("Unable to output non-square grids\n"); + } + } + + free_solver_state(sstate_new); + free_solver_state(sstate); + } + } + + return 0; +} + +#endif + +/* vim: set shiftwidth=4 tabstop=8: */ |