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puzzles/loopy.c
Simon Tatham b16eece9fc New puzzle! Or rather, new-ish, because this one has been lying around 
in the 'unfinished' directory for a while, and has now been finished
up thanks to James Harvey putting in some effort and galvanising me to
put in the rest. This is 'Pearl', an implementation of Nikoli's 'Masyu'.

The code in Loopy that generates a random loop along grid edges to use
as the puzzle solution has been abstracted out into loopgen.[ch] so
that Pearl can use it for its puzzle solutions too. I've also
introduced a new utility module called 'tdq' (for 'to-do queue').

[originally from svn r9379]
2012-01-22 14:14:26 +00:00

3569 lines
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/*
* 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 <assert.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 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(game_params *params, 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(game_params *params, 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(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->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(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(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(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(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(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(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(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(game_params *params, 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(game_state *state)
{
return NULL;
}
static void free_ui(game_ui *ui)
{
}
static char *encode_ui(game_ui *ui)
{
return NULL;
}
static void decode_ui(game_ui *ui, char *encoding)
{
}
static void game_changed_state(game_ui *ui, game_state *oldstate,
game_state *newstate)
{
}
static void game_compute_size(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,
game_params *params, int tilesize)
{
ds->tilesize = tilesize;
}
static float *game_colours(frontend *fe, int *ncolours)
{
float *ret = snewn(4 * 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, 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(game_state *state, game_ui *ui)
{
return TRUE;
}
static float game_anim_length(game_state *oldstate, game_state *newstate,
int dir, game_ui *ui)
{
return 0.0F;
}
static int game_can_format_as_text_now(game_params *params)
{
if (params->type != 0)
return FALSE;
return TRUE;
}
static char *game_text_format(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(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->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, game_params *params, 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->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 *dsf;
int num_faces = g->num_faces;
int i;
int infinite_area, finite_area;
int loops_found = 0;
int found_edge_not_in_loop = FALSE;
memset(state->line_errors, 0, g->num_edges);
/* LL implementation of SGT's idea:
* A loop will partition the grid into an inside and an outside.
* If there is more than one loop, the grid will be partitioned into
* even more distinct regions. We can therefore track equivalence of
* faces, by saying that two faces are equivalent when there is a non-YES
* edge between them.
* We could keep track of the number of connected components, by counting
* the number of dsf-merges that aren't no-ops.
* But we're only interested in 3 separate cases:
* no loops, one loop, more than one loop.
*
* No loops: all faces are equivalent to the infinite face.
* One loop: only two equivalence classes - finite and infinite.
* >= 2 loops: there are 2 distinct finite regions.
*
* So we simply make two passes through all the edges.
* In the first pass, we dsf-merge the two faces bordering each non-YES
* edge.
* In the second pass, we look for YES-edges bordering:
* a) two non-equivalent faces.
* b) two non-equivalent faces, and one of them is part of a different
* finite area from the first finite area we've seen.
*
* An occurrence of a) means there is at least one loop.
* An occurrence of b) means there is more than one loop.
* Edges satisfying a) are marked as errors.
*
* While we're at it, we set a flag if we find a YES edge that is not
* part of a loop.
* This information will help decide, if there's a single loop, whether it
* is a candidate for being a solution (that is, all YES edges are part of
* this loop).
*
* If there is a candidate loop, we then go through all clues and check
* they are all satisfied. If so, we have found a solution and we can
* unmark all line_errors.
*/
/* Infinite face is at the end - its index is num_faces.
* This macro is just to make this obvious! */
#define INF_FACE num_faces
dsf = snewn(num_faces + 1, int);
dsf_init(dsf, num_faces + 1);
/* First pass */
for (i = 0; i < g->num_edges; i++) {
grid_edge *e = g->edges + i;
int f1 = e->face1 ? e->face1 - g->faces : INF_FACE;
int f2 = e->face2 ? e->face2 - g->faces : INF_FACE;
if (state->lines[i] != LINE_YES)
dsf_merge(dsf, f1, f2);
}
/* Second pass */
infinite_area = dsf_canonify(dsf, INF_FACE);
finite_area = -1;
for (i = 0; i < g->num_edges; i++) {
grid_edge *e = g->edges + i;
int f1 = e->face1 ? e->face1 - g->faces : INF_FACE;
int can1 = dsf_canonify(dsf, f1);
int f2 = e->face2 ? e->face2 - g->faces : INF_FACE;
int can2 = dsf_canonify(dsf, f2);
if (state->lines[i] != LINE_YES) continue;
if (can1 == can2) {
/* Faces are equivalent, so this edge not part of a loop */
found_edge_not_in_loop = TRUE;
continue;
}
state->line_errors[i] = TRUE;
if (loops_found == 0) loops_found = 1;
/* Don't bother with further checks if we've already found 2 loops */
if (loops_found == 2) continue;
if (finite_area == -1) {
/* Found our first finite area */
if (can1 != infinite_area)
finite_area = can1;
else
finite_area = can2;
}
/* Have we found a second area? */
if (finite_area != -1) {
if (can1 != infinite_area && can1 != finite_area) {
loops_found = 2;
continue;
}
if (can2 != infinite_area && can2 != finite_area) {
loops_found = 2;
}
}
}
/*
printf("loops_found = %d\n", loops_found);
printf("found_edge_not_in_loop = %s\n",
found_edge_not_in_loop ? "TRUE" : "FALSE");
*/
sfree(dsf); /* No longer need the dsf */
/* Have we found a candidate loop? */
if (loops_found == 1 && !found_edge_not_in_loop) {
/* Yes, so check all clues are satisfied */
int found_clue_violation = FALSE;
for (i = 0; i < num_faces; i++) {
int c = state->clues[i];
if (c >= 0) {
if (face_order(state, i, LINE_YES) != c) {
found_clue_violation = TRUE;
break;
}
}
}
if (!found_clue_violation) {
/* The loop is good */
memset(state->line_errors, 0, g->num_edges);
return TRUE; /* No need to bother checking for dot violations */
}
}
/* Check for dot violations */
for (i = 0; i < g->num_dots; 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;
}
}
}
return FALSE;
}
/* ----------------------------------------------------------------------
* 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(game_state *state, game_state *currstate,
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(game_state *state, game_ui *ui, 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(game_state *state, 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,
game_state *state, int i)
{
grid *g = state->game_grid;
grid_face *f = g->faces + i;
int x, y;
char c[3];
if (state->clues[i] < 10) {
c[0] = CLUE2CHAR(state->clues[i]);
c[1] = '\0';
} else {
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,
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,
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,
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, game_state *oldstate,
game_state *state, int dir, 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;
else {
/* First, trundle through the faces. */
for (i = 0; i < g->num_faces; i++) {
grid_face *f = g->faces + i;
int sides = f->order;
int clue_mistake;
int clue_satisfied;
int n = state->clues[i];
if (n < 0)
continue;
clue_mistake = (face_order(state, i, LINE_YES) > n ||
face_order(state, i, LINE_NO ) > (sides-n));
clue_satisfied = (face_order(state, i, LINE_YES) == n &&
face_order(state, i, LINE_NO ) == (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(game_state *oldstate, 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(game_state *state)
{
return state->solved ? +1 : 0;
}
static void game_print_size(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, 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[2];
int x, y;
c[0] = CLUE2CHAR(clue);
c[1] = '\0';
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: */
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