ref: 22ab2c0b8237e1c51fdb479668ab764900f7d0c0
dir: /solo.c/
/*
* solo.c: the number-placing puzzle most popularly known as `Sudoku'.
*
* TODO:
*
* - can we do anything about nasty centring of text in GTK? It
* seems to be taking ascenders/descenders into account when
* centring. Ick.
*
* - implement stronger modes of reasoning in nsolve, thus
* enabling harder puzzles
* + and having done that, supply configurable difficulty
* levels
*
* - it might still be nice to do some prioritisation on the
* removal of numbers from the grid
* + one possibility is to try to minimise the maximum number
* of filled squares in any block, which in particular ought
* to enforce never leaving a completely filled block in the
* puzzle as presented.
* + be careful of being too clever here, though, until after
* I've tried implementing difficulty levels. It's not
* impossible that those might impose much more important
* constraints on this process.
*
* - alternative interface modes
* + sudoku.com's Windows program has a palette of possible
* entries; you select a palette entry first and then click
* on the square you want it to go in, thus enabling
* mouse-only play. Useful for PDAs! I don't think it's
* actually incompatible with the current highlight-then-type
* approach: you _either_ highlight a palette entry and then
* click, _or_ you highlight a square and then type. At most
* one thing is ever highlighted at a time, so there's no way
* to confuse the two.
* + `pencil marks' might be useful for more subtle forms of
* deduction, once we implement creation of puzzles that
* require it.
*/
/*
* Solo puzzles need to be square overall (since each row and each
* column must contain one of every digit), but they need not be
* subdivided the same way internally. I am going to adopt a
* convention whereby I _always_ refer to `r' as the number of rows
* of _big_ divisions, and `c' as the number of columns of _big_
* divisions. Thus, a 2c by 3r puzzle looks something like this:
*
* 4 5 1 | 2 6 3
* 6 3 2 | 5 4 1
* ------+------ (Of course, you can't subdivide it the other way
* 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the
* 3 2 6 | 4 1 5 top left would conflict with the 4 in the second
* ------+------ box down on the left-hand side.)
* 5 1 4 | 3 2 6
* 2 6 3 | 1 5 4
*
* The need for a strong naming convention should now be clear:
* each small box is two rows of digits by three columns, while the
* overall puzzle has three rows of small boxes by two columns. So
* I will (hopefully) consistently use `r' to denote the number of
* rows _of small boxes_ (here 3), which is also the number of
* columns of digits in each small box; and `c' vice versa (here
* 2).
*
* I'm also going to choose arbitrarily to list c first wherever
* possible: the above is a 2x3 puzzle, not a 3x2 one.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include "puzzles.h"
/*
* To save space, I store digits internally as unsigned char. This
* imposes a hard limit of 255 on the order of the puzzle. Since
* even a 5x5 takes unacceptably long to generate, I don't see this
* as a serious limitation unless something _really_ impressive
* happens in computing technology; but here's a typedef anyway for
* general good practice.
*/
typedef unsigned char digit;
#define ORDER_MAX 255
#define TILE_SIZE 32
#define BORDER 18
#define FLASH_TIME 0.4F
enum { SYMM_NONE, SYMM_ROT2, SYMM_ROT4, SYMM_REF4 };
enum {
COL_BACKGROUND,
COL_GRID,
COL_CLUE,
COL_USER,
COL_HIGHLIGHT,
NCOLOURS
};
struct game_params {
int c, r, symm;
};
struct game_state {
int c, r;
digit *grid;
unsigned char *immutable; /* marks which digits are clues */
int completed;
};
static game_params *default_params(void)
{
game_params *ret = snew(game_params);
ret->c = ret->r = 3;
ret->symm = SYMM_ROT2; /* a plausible default */
return ret;
}
static int game_fetch_preset(int i, char **name, game_params **params)
{
game_params *ret;
int c, r;
char buf[80];
switch (i) {
case 0: c = 2, r = 2; break;
case 1: c = 2, r = 3; break;
case 2: c = 3, r = 3; break;
case 3: c = 3, r = 4; break;
case 4: c = 4, r = 4; break;
default: return FALSE;
}
sprintf(buf, "%dx%d", c, r);
*name = dupstr(buf);
*params = ret = snew(game_params);
ret->c = c;
ret->r = r;
ret->symm = SYMM_ROT2;
/* FIXME: difficulty presets? */
return TRUE;
}
static void free_params(game_params *params)
{
sfree(params);
}
static game_params *dup_params(game_params *params)
{
game_params *ret = snew(game_params);
*ret = *params; /* structure copy */
return ret;
}
static game_params *decode_params(char const *string)
{
game_params *ret = default_params();
ret->c = ret->r = atoi(string);
ret->symm = SYMM_ROT2;
while (*string && isdigit((unsigned char)*string)) string++;
if (*string == 'x') {
string++;
ret->r = atoi(string);
while (*string && isdigit((unsigned char)*string)) string++;
}
if (*string == 'r' || *string == 'm' || *string == 'a') {
int sn, sc;
sc = *string++;
sn = atoi(string);
while (*string && isdigit((unsigned char)*string)) string++;
if (sc == 'm' && sn == 4)
ret->symm = SYMM_REF4;
if (sc == 'r' && sn == 4)
ret->symm = SYMM_ROT4;
if (sc == 'r' && sn == 2)
ret->symm = SYMM_ROT2;
if (sc == 'a')
ret->symm = SYMM_NONE;
}
/* FIXME: difficulty levels */
return ret;
}
static char *encode_params(game_params *params)
{
char str[80];
/*
* Symmetry is a game generation preference and hence is left
* out of the encoding. Users can add it back in as they see
* fit.
*/
sprintf(str, "%dx%d", params->c, params->r);
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 = "Columns of sub-blocks";
ret[0].type = C_STRING;
sprintf(buf, "%d", params->c);
ret[0].sval = dupstr(buf);
ret[0].ival = 0;
ret[1].name = "Rows of sub-blocks";
ret[1].type = C_STRING;
sprintf(buf, "%d", params->r);
ret[1].sval = dupstr(buf);
ret[1].ival = 0;
ret[2].name = "Symmetry";
ret[2].type = C_CHOICES;
ret[2].sval = ":None:2-way rotation:4-way rotation:4-way mirror";
ret[2].ival = params->symm;
/*
* FIXME: difficulty level.
*/
ret[3].name = NULL;
ret[3].type = C_END;
ret[3].sval = NULL;
ret[3].ival = 0;
return ret;
}
static game_params *custom_params(config_item *cfg)
{
game_params *ret = snew(game_params);
ret->c = atoi(cfg[0].sval);
ret->r = atoi(cfg[1].sval);
ret->symm = cfg[2].ival;
return ret;
}
static char *validate_params(game_params *params)
{
if (params->c < 2 || params->r < 2)
return "Both dimensions must be at least 2";
if (params->c > ORDER_MAX || params->r > ORDER_MAX)
return "Dimensions greater than "STR(ORDER_MAX)" are not supported";
return NULL;
}
/* ----------------------------------------------------------------------
* Full recursive Solo solver.
*
* The algorithm for this solver is shamelessly copied from a
* Python solver written by Andrew Wilkinson (which is GPLed, but
* I've reused only ideas and no code). It mostly just does the
* obvious recursive thing: pick an empty square, put one of the
* possible digits in it, recurse until all squares are filled,
* backtrack and change some choices if necessary.
*
* The clever bit is that every time it chooses which square to
* fill in next, it does so by counting the number of _possible_
* numbers that can go in each square, and it prioritises so that
* it picks a square with the _lowest_ number of possibilities. The
* idea is that filling in lots of the obvious bits (particularly
* any squares with only one possibility) will cut down on the list
* of possibilities for other squares and hence reduce the enormous
* search space as much as possible as early as possible.
*
* In practice the algorithm appeared to work very well; run on
* sample problems from the Times it completed in well under a
* second on my G5 even when written in Python, and given an empty
* grid (so that in principle it would enumerate _all_ solved
* grids!) it found the first valid solution just as quickly. So
* with a bit more randomisation I see no reason not to use this as
* my grid generator.
*/
/*
* Internal data structure used in solver to keep track of
* progress.
*/
struct rsolve_coord { int x, y, r; };
struct rsolve_usage {
int c, r, cr; /* cr == c*r */
/* grid is a copy of the input grid, modified as we go along */
digit *grid;
/* row[y*cr+n-1] TRUE if digit n has been placed in row y */
unsigned char *row;
/* col[x*cr+n-1] TRUE if digit n has been placed in row x */
unsigned char *col;
/* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
unsigned char *blk;
/* This lists all the empty spaces remaining in the grid. */
struct rsolve_coord *spaces;
int nspaces;
/* If we need randomisation in the solve, this is our random state. */
random_state *rs;
/* Number of solutions so far found, and maximum number we care about. */
int solns, maxsolns;
};
/*
* The real recursive step in the solving function.
*/
static void rsolve_real(struct rsolve_usage *usage, digit *grid)
{
int c = usage->c, r = usage->r, cr = usage->cr;
int i, j, n, sx, sy, bestm, bestr;
int *digits;
/*
* Firstly, check for completion! If there are no spaces left
* in the grid, we have a solution.
*/
if (usage->nspaces == 0) {
if (!usage->solns) {
/*
* This is our first solution, so fill in the output grid.
*/
memcpy(grid, usage->grid, cr * cr);
}
usage->solns++;
return;
}
/*
* Otherwise, there must be at least one space. Find the most
* constrained space, using the `r' field as a tie-breaker.
*/
bestm = cr+1; /* so that any space will beat it */
bestr = 0;
i = sx = sy = -1;
for (j = 0; j < usage->nspaces; j++) {
int x = usage->spaces[j].x, y = usage->spaces[j].y;
int m;
/*
* Find the number of digits that could go in this space.
*/
m = 0;
for (n = 0; n < cr; n++)
if (!usage->row[y*cr+n] && !usage->col[x*cr+n] &&
!usage->blk[((y/c)*c+(x/r))*cr+n])
m++;
if (m < bestm || (m == bestm && usage->spaces[j].r < bestr)) {
bestm = m;
bestr = usage->spaces[j].r;
sx = x;
sy = y;
i = j;
}
}
/*
* Swap that square into the final place in the spaces array,
* so that decrementing nspaces will remove it from the list.
*/
if (i != usage->nspaces-1) {
struct rsolve_coord t;
t = usage->spaces[usage->nspaces-1];
usage->spaces[usage->nspaces-1] = usage->spaces[i];
usage->spaces[i] = t;
}
/*
* Now we've decided which square to start our recursion at,
* simply go through all possible values, shuffling them
* randomly first if necessary.
*/
digits = snewn(bestm, int);
j = 0;
for (n = 0; n < cr; n++)
if (!usage->row[sy*cr+n] && !usage->col[sx*cr+n] &&
!usage->blk[((sy/c)*c+(sx/r))*cr+n]) {
digits[j++] = n+1;
}
if (usage->rs) {
/* shuffle */
for (i = j; i > 1; i--) {
int p = random_upto(usage->rs, i);
if (p != i-1) {
int t = digits[p];
digits[p] = digits[i-1];
digits[i-1] = t;
}
}
}
/* And finally, go through the digit list and actually recurse. */
for (i = 0; i < j; i++) {
n = digits[i];
/* Update the usage structure to reflect the placing of this digit. */
usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] =
usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = TRUE;
usage->grid[sy*cr+sx] = n;
usage->nspaces--;
/* Call the solver recursively. */
rsolve_real(usage, grid);
/*
* If we have seen as many solutions as we need, terminate
* all processing immediately.
*/
if (usage->solns >= usage->maxsolns)
break;
/* Revert the usage structure. */
usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] =
usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = FALSE;
usage->grid[sy*cr+sx] = 0;
usage->nspaces++;
}
sfree(digits);
}
/*
* Entry point to solver. You give it dimensions and a starting
* grid, which is simply an array of N^4 digits. In that array, 0
* means an empty square, and 1..N mean a clue square.
*
* Return value is the number of solutions found; searching will
* stop after the provided `max'. (Thus, you can pass max==1 to
* indicate that you only care about finding _one_ solution, or
* max==2 to indicate that you want to know the difference between
* a unique and non-unique solution.) The input parameter `grid' is
* also filled in with the _first_ (or only) solution found by the
* solver.
*/
static int rsolve(int c, int r, digit *grid, random_state *rs, int max)
{
struct rsolve_usage *usage;
int x, y, cr = c*r;
int ret;
/*
* Create an rsolve_usage structure.
*/
usage = snew(struct rsolve_usage);
usage->c = c;
usage->r = r;
usage->cr = cr;
usage->grid = snewn(cr * cr, digit);
memcpy(usage->grid, grid, cr * cr);
usage->row = snewn(cr * cr, unsigned char);
usage->col = snewn(cr * cr, unsigned char);
usage->blk = snewn(cr * cr, unsigned char);
memset(usage->row, FALSE, cr * cr);
memset(usage->col, FALSE, cr * cr);
memset(usage->blk, FALSE, cr * cr);
usage->spaces = snewn(cr * cr, struct rsolve_coord);
usage->nspaces = 0;
usage->solns = 0;
usage->maxsolns = max;
usage->rs = rs;
/*
* Now fill it in with data from the input grid.
*/
for (y = 0; y < cr; y++) {
for (x = 0; x < cr; x++) {
int v = grid[y*cr+x];
if (v == 0) {
usage->spaces[usage->nspaces].x = x;
usage->spaces[usage->nspaces].y = y;
if (rs)
usage->spaces[usage->nspaces].r = random_bits(rs, 31);
else
usage->spaces[usage->nspaces].r = usage->nspaces;
usage->nspaces++;
} else {
usage->row[y*cr+v-1] = TRUE;
usage->col[x*cr+v-1] = TRUE;
usage->blk[((y/c)*c+(x/r))*cr+v-1] = TRUE;
}
}
}
/*
* Run the real recursive solving function.
*/
rsolve_real(usage, grid);
ret = usage->solns;
/*
* Clean up the usage structure now we have our answer.
*/
sfree(usage->spaces);
sfree(usage->blk);
sfree(usage->col);
sfree(usage->row);
sfree(usage->grid);
sfree(usage);
/*
* And return.
*/
return ret;
}
/* ----------------------------------------------------------------------
* End of recursive solver code.
*/
/* ----------------------------------------------------------------------
* Less capable non-recursive solver. This one is used to check
* solubility of a grid as we gradually remove numbers from it: by
* verifying a grid using this solver we can ensure it isn't _too_
* hard (e.g. does not actually require guessing and backtracking).
*
* It supports a variety of specific modes of reasoning. By
* enabling or disabling subsets of these modes we can arrange a
* range of difficulty levels.
*/
/*
* Modes of reasoning currently supported:
*
* - Positional elimination: a number must go in a particular
* square because all the other empty squares in a given
* row/col/blk are ruled out.
*
* - Numeric elimination: a square must have a particular number
* in because all the other numbers that could go in it are
* ruled out.
*
* More advanced modes of reasoning I'd like to support in future:
*
* - Intersectional elimination: given two domains which overlap
* (hence one must be a block, and the other can be a row or
* col), if the possible locations for a particular number in
* one of the domains can be narrowed down to the overlap, then
* that number can be ruled out everywhere but the overlap in
* the other domain too.
*
* - Setwise numeric elimination: if there is a subset of the
* empty squares within a domain such that the union of the
* possible numbers in that subset has the same size as the
* subset itself, then those numbers can be ruled out everywhere
* else in the domain. (For example, if there are five empty
* squares and the possible numbers in each are 12, 23, 13, 134
* and 1345, then the first three empty squares form such a
* subset: the numbers 1, 2 and 3 _must_ be in those three
* squares in some permutation, and hence we can deduce none of
* them can be in the fourth or fifth squares.)
*
* - Setwise positional elimination: if there is a subset of the
* unplaced numbers within a domain such that the union of all
* their possible positions has the same size as the subset
* itself, then all other numbers can be ruled out for those
* positions.
*/
/*
* Within this solver, I'm going to transform all y-coordinates by
* inverting the significance of the block number and the position
* within the block. That is, we will start with the top row of
* each block in order, then the second row of each block in order,
* etc.
*
* This transformation has the enormous advantage that it means
* every row, column _and_ block is described by an arithmetic
* progression of coordinates within the cubic array, so that I can
* use the same very simple function to do blockwise, row-wise and
* column-wise elimination.
*/
#define YTRANS(y) (((y)%c)*r+(y)/c)
#define YUNTRANS(y) (((y)%r)*c+(y)/r)
struct nsolve_usage {
int c, r, cr;
/*
* We set up a cubic array, indexed by x, y and digit; each
* element of this array is TRUE or FALSE according to whether
* or not that digit _could_ in principle go in that position.
*
* The way to index this array is cube[(x*cr+y)*cr+n-1].
* y-coordinates in here are transformed.
*/
unsigned char *cube;
/*
* This is the grid in which we write down our final
* deductions. y-coordinates in here are _not_ transformed.
*/
digit *grid;
/*
* Now we keep track, at a slightly higher level, of what we
* have yet to work out, to prevent doing the same deduction
* many times.
*/
/* row[y*cr+n-1] TRUE if digit n has been placed in row y */
unsigned char *row;
/* col[x*cr+n-1] TRUE if digit n has been placed in row x */
unsigned char *col;
/* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
unsigned char *blk;
};
#define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1)
#define cube(x,y,n) (usage->cube[cubepos(x,y,n)])
/*
* Function called when we are certain that a particular square has
* a particular number in it. The y-coordinate passed in here is
* transformed.
*/
static void nsolve_place(struct nsolve_usage *usage, int x, int y, int n)
{
int c = usage->c, r = usage->r, cr = usage->cr;
int i, j, bx, by;
assert(cube(x,y,n));
/*
* Rule out all other numbers in this square.
*/
for (i = 1; i <= cr; i++)
if (i != n)
cube(x,y,i) = FALSE;
/*
* Rule out this number in all other positions in the row.
*/
for (i = 0; i < cr; i++)
if (i != y)
cube(x,i,n) = FALSE;
/*
* Rule out this number in all other positions in the column.
*/
for (i = 0; i < cr; i++)
if (i != x)
cube(i,y,n) = FALSE;
/*
* Rule out this number in all other positions in the block.
*/
bx = (x/r)*r;
by = y % r;
for (i = 0; i < r; i++)
for (j = 0; j < c; j++)
if (bx+i != x || by+j*r != y)
cube(bx+i,by+j*r,n) = FALSE;
/*
* Enter the number in the result grid.
*/
usage->grid[YUNTRANS(y)*cr+x] = n;
/*
* Cross out this number from the list of numbers left to place
* in its row, its column and its block.
*/
usage->row[y*cr+n-1] = usage->col[x*cr+n-1] =
usage->blk[((y/c)*c+(x/r))*cr+n-1] = TRUE;
}
static int nsolve_elim(struct nsolve_usage *usage, int start, int step)
{
int c = usage->c, r = usage->r, cr = c*r;
int fpos, m, i;
/*
* Count the number of set bits within this section of the
* cube.
*/
m = 0;
fpos = -1;
for (i = 0; i < cr; i++)
if (usage->cube[start+i*step]) {
fpos = start+i*step;
m++;
}
if (m == 1) {
int x, y, n;
assert(fpos >= 0);
n = 1 + fpos % cr;
y = fpos / cr;
x = y / cr;
y %= cr;
if (!usage->grid[YUNTRANS(y)*cr+x]) {
nsolve_place(usage, x, y, n);
return TRUE;
}
}
return FALSE;
}
static int nsolve(int c, int r, digit *grid)
{
struct nsolve_usage *usage;
int cr = c*r;
int x, y, n;
/*
* Set up a usage structure as a clean slate (everything
* possible).
*/
usage = snew(struct nsolve_usage);
usage->c = c;
usage->r = r;
usage->cr = cr;
usage->cube = snewn(cr*cr*cr, unsigned char);
usage->grid = grid; /* write straight back to the input */
memset(usage->cube, TRUE, cr*cr*cr);
usage->row = snewn(cr * cr, unsigned char);
usage->col = snewn(cr * cr, unsigned char);
usage->blk = snewn(cr * cr, unsigned char);
memset(usage->row, FALSE, cr * cr);
memset(usage->col, FALSE, cr * cr);
memset(usage->blk, FALSE, cr * cr);
/*
* Place all the clue numbers we are given.
*/
for (x = 0; x < cr; x++)
for (y = 0; y < cr; y++)
if (grid[y*cr+x])
nsolve_place(usage, x, YTRANS(y), grid[y*cr+x]);
/*
* Now loop over the grid repeatedly trying all permitted modes
* of reasoning. The loop terminates if we complete an
* iteration without making any progress; we then return
* failure or success depending on whether the grid is full or
* not.
*/
while (1) {
cont:
/*
* Blockwise positional elimination.
*/
for (x = 0; x < cr; x += r)
for (y = 0; y < r; y++)
for (n = 1; n <= cr; n++)
if (!usage->blk[(y*c+(x/r))*cr+n-1] &&
nsolve_elim(usage, cubepos(x,y,n), r*cr))
goto cont;
/*
* Row-wise positional elimination.
*/
for (y = 0; y < cr; y++)
for (n = 1; n <= cr; n++)
if (!usage->row[y*cr+n-1] &&
nsolve_elim(usage, cubepos(0,y,n), cr*cr))
goto cont;
/*
* Column-wise positional elimination.
*/
for (x = 0; x < cr; x++)
for (n = 1; n <= cr; n++)
if (!usage->col[x*cr+n-1] &&
nsolve_elim(usage, cubepos(x,0,n), cr))
goto cont;
/*
* Numeric elimination.
*/
for (x = 0; x < cr; x++)
for (y = 0; y < cr; y++)
if (!usage->grid[YUNTRANS(y)*cr+x] &&
nsolve_elim(usage, cubepos(x,y,1), 1))
goto cont;
/*
* If we reach here, we have made no deductions in this
* iteration, so the algorithm terminates.
*/
break;
}
sfree(usage->cube);
sfree(usage->row);
sfree(usage->col);
sfree(usage->blk);
sfree(usage);
for (x = 0; x < cr; x++)
for (y = 0; y < cr; y++)
if (!grid[y*cr+x])
return FALSE;
return TRUE;
}
/* ----------------------------------------------------------------------
* End of non-recursive solver code.
*/
/*
* Check whether a grid contains a valid complete puzzle.
*/
static int check_valid(int c, int r, digit *grid)
{
int cr = c*r;
unsigned char *used;
int x, y, n;
used = snewn(cr, unsigned char);
/*
* Check that each row contains precisely one of everything.
*/
for (y = 0; y < cr; y++) {
memset(used, FALSE, cr);
for (x = 0; x < cr; x++)
if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr)
used[grid[y*cr+x]-1] = TRUE;
for (n = 0; n < cr; n++)
if (!used[n]) {
sfree(used);
return FALSE;
}
}
/*
* Check that each column contains precisely one of everything.
*/
for (x = 0; x < cr; x++) {
memset(used, FALSE, cr);
for (y = 0; y < cr; y++)
if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr)
used[grid[y*cr+x]-1] = TRUE;
for (n = 0; n < cr; n++)
if (!used[n]) {
sfree(used);
return FALSE;
}
}
/*
* Check that each block contains precisely one of everything.
*/
for (x = 0; x < cr; x += r) {
for (y = 0; y < cr; y += c) {
int xx, yy;
memset(used, FALSE, cr);
for (xx = x; xx < x+r; xx++)
for (yy = 0; yy < y+c; yy++)
if (grid[yy*cr+xx] > 0 && grid[yy*cr+xx] <= cr)
used[grid[yy*cr+xx]-1] = TRUE;
for (n = 0; n < cr; n++)
if (!used[n]) {
sfree(used);
return FALSE;
}
}
}
sfree(used);
return TRUE;
}
static void symmetry_limit(game_params *params, int *xlim, int *ylim, int s)
{
int c = params->c, r = params->r, cr = c*r;
switch (s) {
case SYMM_NONE:
*xlim = *ylim = cr;
break;
case SYMM_ROT2:
*xlim = (cr+1) / 2;
*ylim = cr;
break;
case SYMM_REF4:
case SYMM_ROT4:
*xlim = *ylim = (cr+1) / 2;
break;
}
}
static int symmetries(game_params *params, int x, int y, int *output, int s)
{
int c = params->c, r = params->r, cr = c*r;
int i = 0;
*output++ = x;
*output++ = y;
i++;
switch (s) {
case SYMM_NONE:
break; /* just x,y is all we need */
case SYMM_REF4:
case SYMM_ROT4:
switch (s) {
case SYMM_REF4:
*output++ = cr - 1 - x;
*output++ = y;
i++;
*output++ = x;
*output++ = cr - 1 - y;
i++;
break;
case SYMM_ROT4:
*output++ = cr - 1 - y;
*output++ = x;
i++;
*output++ = y;
*output++ = cr - 1 - x;
i++;
break;
}
/* fall through */
case SYMM_ROT2:
*output++ = cr - 1 - x;
*output++ = cr - 1 - y;
i++;
break;
}
return i;
}
static char *new_game_seed(game_params *params, random_state *rs)
{
int c = params->c, r = params->r, cr = c*r;
int area = cr*cr;
digit *grid, *grid2;
struct xy { int x, y; } *locs;
int nlocs;
int ret;
char *seed;
int coords[16], ncoords;
int xlim, ylim;
/*
* Start the recursive solver with an empty grid to generate a
* random solved state.
*/
grid = snewn(area, digit);
memset(grid, 0, area);
ret = rsolve(c, r, grid, rs, 1);
assert(ret == 1);
assert(check_valid(c, r, grid));
/*
* Now we have a solved grid, start removing things from it
* while preserving solubility.
*/
locs = snewn(area, struct xy);
grid2 = snewn(area, digit);
symmetry_limit(params, &xlim, &ylim, params->symm);
while (1) {
int x, y, i, j;
/*
* Iterate over the grid and enumerate all the filled
* squares we could empty.
*/
nlocs = 0;
for (x = 0; x < xlim; x++)
for (y = 0; y < ylim; y++)
if (grid[y*cr+x]) {
locs[nlocs].x = x;
locs[nlocs].y = y;
nlocs++;
}
/*
* Now shuffle that list.
*/
for (i = nlocs; i > 1; i--) {
int p = random_upto(rs, i);
if (p != i-1) {
struct xy t = locs[p];
locs[p] = locs[i-1];
locs[i-1] = t;
}
}
/*
* Now loop over the shuffled list and, for each element,
* see whether removing that element (and its reflections)
* from the grid will still leave the grid soluble by
* nsolve.
*/
for (i = 0; i < nlocs; i++) {
x = locs[i].x;
y = locs[i].y;
memcpy(grid2, grid, area);
ncoords = symmetries(params, x, y, coords, params->symm);
for (j = 0; j < ncoords; j++)
grid2[coords[2*j+1]*cr+coords[2*j]] = 0;
if (nsolve(c, r, grid2)) {
for (j = 0; j < ncoords; j++)
grid[coords[2*j+1]*cr+coords[2*j]] = 0;
break;
}
}
if (i == nlocs) {
/*
* There was nothing we could remove without destroying
* solvability.
*/
break;
}
}
sfree(grid2);
sfree(locs);
/*
* Now we have the grid as it will be presented to the user.
* Encode it in a game seed.
*/
{
char *p;
int run, i;
seed = snewn(5 * area, char);
p = seed;
run = 0;
for (i = 0; i <= area; i++) {
int n = (i < area ? grid[i] : -1);
if (!n)
run++;
else {
if (run) {
while (run > 0) {
int c = 'a' - 1 + run;
if (run > 26)
c = 'z';
*p++ = c;
run -= c - ('a' - 1);
}
} else {
/*
* If there's a number in the very top left or
* bottom right, there's no point putting an
* unnecessary _ before or after it.
*/
if (p > seed && n > 0)
*p++ = '_';
}
if (n > 0)
p += sprintf(p, "%d", n);
run = 0;
}
}
assert(p - seed < 5 * area);
*p++ = '\0';
seed = sresize(seed, p - seed, char);
}
sfree(grid);
return seed;
}
static char *validate_seed(game_params *params, char *seed)
{
int area = params->r * params->r * params->c * params->c;
int squares = 0;
while (*seed) {
int n = *seed++;
if (n >= 'a' && n <= 'z') {
squares += n - 'a' + 1;
} else if (n == '_') {
/* do nothing */;
} else if (n > '0' && n <= '9') {
squares++;
while (*seed >= '0' && *seed <= '9')
seed++;
} else
return "Invalid character in game specification";
}
if (squares < area)
return "Not enough data to fill grid";
if (squares > area)
return "Too much data to fit in grid";
return NULL;
}
static game_state *new_game(game_params *params, char *seed)
{
game_state *state = snew(game_state);
int c = params->c, r = params->r, cr = c*r, area = cr * cr;
int i;
state->c = params->c;
state->r = params->r;
state->grid = snewn(area, digit);
state->immutable = snewn(area, unsigned char);
memset(state->immutable, FALSE, area);
state->completed = FALSE;
i = 0;
while (*seed) {
int n = *seed++;
if (n >= 'a' && n <= 'z') {
int run = n - 'a' + 1;
assert(i + run <= area);
while (run-- > 0)
state->grid[i++] = 0;
} else if (n == '_') {
/* do nothing */;
} else if (n > '0' && n <= '9') {
assert(i < area);
state->immutable[i] = TRUE;
state->grid[i++] = atoi(seed-1);
while (*seed >= '0' && *seed <= '9')
seed++;
} else {
assert(!"We can't get here");
}
}
assert(i == area);
return state;
}
static game_state *dup_game(game_state *state)
{
game_state *ret = snew(game_state);
int c = state->c, r = state->r, cr = c*r, area = cr * cr;
ret->c = state->c;
ret->r = state->r;
ret->grid = snewn(area, digit);
memcpy(ret->grid, state->grid, area);
ret->immutable = snewn(area, unsigned char);
memcpy(ret->immutable, state->immutable, area);
ret->completed = state->completed;
return ret;
}
static void free_game(game_state *state)
{
sfree(state->immutable);
sfree(state->grid);
sfree(state);
}
struct game_ui {
/*
* These are the coordinates of the currently highlighted
* square on the grid, or -1,-1 if there isn't one. When there
* is, pressing a valid number or letter key or Space will
* enter that number or letter in the grid.
*/
int hx, hy;
};
static game_ui *new_ui(game_state *state)
{
game_ui *ui = snew(game_ui);
ui->hx = ui->hy = -1;
return ui;
}
static void free_ui(game_ui *ui)
{
sfree(ui);
}
static game_state *make_move(game_state *from, game_ui *ui, int x, int y,
int button)
{
int c = from->c, r = from->r, cr = c*r;
int tx, ty;
game_state *ret;
tx = (x + TILE_SIZE - BORDER) / TILE_SIZE - 1;
ty = (y + TILE_SIZE - BORDER) / TILE_SIZE - 1;
if (tx >= 0 && tx < cr && ty >= 0 && ty < cr && button == LEFT_BUTTON) {
if (tx == ui->hx && ty == ui->hy) {
ui->hx = ui->hy = -1;
} else {
ui->hx = tx;
ui->hy = ty;
}
return from; /* UI activity occurred */
}
if (ui->hx != -1 && ui->hy != -1 &&
((button >= '1' && button <= '9' && button - '0' <= cr) ||
(button >= 'a' && button <= 'z' && button - 'a' + 10 <= cr) ||
(button >= 'A' && button <= 'Z' && button - 'A' + 10 <= cr) ||
button == ' ')) {
int n = button - '0';
if (button >= 'A' && button <= 'Z')
n = button - 'A' + 10;
if (button >= 'a' && button <= 'z')
n = button - 'a' + 10;
if (button == ' ')
n = 0;
if (from->immutable[ui->hy*cr+ui->hx])
return NULL; /* can't overwrite this square */
ret = dup_game(from);
ret->grid[ui->hy*cr+ui->hx] = n;
ui->hx = ui->hy = -1;
/*
* We've made a real change to the grid. Check to see
* if the game has been completed.
*/
if (!ret->completed && check_valid(c, r, ret->grid)) {
ret->completed = TRUE;
}
return ret; /* made a valid move */
}
return NULL;
}
/* ----------------------------------------------------------------------
* Drawing routines.
*/
struct game_drawstate {
int started;
int c, r, cr;
digit *grid;
unsigned char *hl;
};
#define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
#define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
static void game_size(game_params *params, int *x, int *y)
{
int c = params->c, r = params->r, cr = c*r;
*x = XSIZE(cr);
*y = YSIZE(cr);
}
static float *game_colours(frontend *fe, game_state *state, int *ncolours)
{
float *ret = snewn(3 * NCOLOURS, float);
frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
ret[COL_GRID * 3 + 0] = 0.0F;
ret[COL_GRID * 3 + 1] = 0.0F;
ret[COL_GRID * 3 + 2] = 0.0F;
ret[COL_CLUE * 3 + 0] = 0.0F;
ret[COL_CLUE * 3 + 1] = 0.0F;
ret[COL_CLUE * 3 + 2] = 0.0F;
ret[COL_USER * 3 + 0] = 0.0F;
ret[COL_USER * 3 + 1] = 0.6F * ret[COL_BACKGROUND * 3 + 1];
ret[COL_USER * 3 + 2] = 0.0F;
ret[COL_HIGHLIGHT * 3 + 0] = 0.85F * ret[COL_BACKGROUND * 3 + 0];
ret[COL_HIGHLIGHT * 3 + 1] = 0.85F * ret[COL_BACKGROUND * 3 + 1];
ret[COL_HIGHLIGHT * 3 + 2] = 0.85F * ret[COL_BACKGROUND * 3 + 2];
*ncolours = NCOLOURS;
return ret;
}
static game_drawstate *game_new_drawstate(game_state *state)
{
struct game_drawstate *ds = snew(struct game_drawstate);
int c = state->c, r = state->r, cr = c*r;
ds->started = FALSE;
ds->c = c;
ds->r = r;
ds->cr = cr;
ds->grid = snewn(cr*cr, digit);
memset(ds->grid, 0, cr*cr);
ds->hl = snewn(cr*cr, unsigned char);
memset(ds->hl, 0, cr*cr);
return ds;
}
static void game_free_drawstate(game_drawstate *ds)
{
sfree(ds->hl);
sfree(ds->grid);
sfree(ds);
}
static void draw_number(frontend *fe, game_drawstate *ds, game_state *state,
int x, int y, int hl)
{
int c = state->c, r = state->r, cr = c*r;
int tx, ty;
int cx, cy, cw, ch;
char str[2];
if (ds->grid[y*cr+x] == state->grid[y*cr+x] && ds->hl[y*cr+x] == hl)
return; /* no change required */
tx = BORDER + x * TILE_SIZE + 2;
ty = BORDER + y * TILE_SIZE + 2;
cx = tx;
cy = ty;
cw = TILE_SIZE-3;
ch = TILE_SIZE-3;
if (x % r)
cx--, cw++;
if ((x+1) % r)
cw++;
if (y % c)
cy--, ch++;
if ((y+1) % c)
ch++;
clip(fe, cx, cy, cw, ch);
/* background needs erasing? */
if (ds->grid[y*cr+x] || ds->hl[y*cr+x] != hl)
draw_rect(fe, cx, cy, cw, ch, hl ? COL_HIGHLIGHT : COL_BACKGROUND);
/* new number needs drawing? */
if (state->grid[y*cr+x]) {
str[1] = '\0';
str[0] = state->grid[y*cr+x] + '0';
if (str[0] > '9')
str[0] += 'a' - ('9'+1);
draw_text(fe, tx + TILE_SIZE/2, ty + TILE_SIZE/2,
FONT_VARIABLE, TILE_SIZE/2, ALIGN_VCENTRE | ALIGN_HCENTRE,
state->immutable[y*cr+x] ? COL_CLUE : COL_USER, str);
}
unclip(fe);
draw_update(fe, cx, cy, cw, ch);
ds->grid[y*cr+x] = state->grid[y*cr+x];
ds->hl[y*cr+x] = hl;
}
static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
game_state *state, int dir, game_ui *ui,
float animtime, float flashtime)
{
int c = state->c, r = state->r, cr = c*r;
int x, y;
if (!ds->started) {
/*
* The initial contents of the window are not guaranteed
* and can vary with front ends. To be on the safe side,
* all games should start by drawing a big
* background-colour rectangle covering the whole window.
*/
draw_rect(fe, 0, 0, XSIZE(cr), YSIZE(cr), COL_BACKGROUND);
/*
* Draw the grid.
*/
for (x = 0; x <= cr; x++) {
int thick = (x % r ? 0 : 1);
draw_rect(fe, BORDER + x*TILE_SIZE - thick, BORDER-1,
1+2*thick, cr*TILE_SIZE+3, COL_GRID);
}
for (y = 0; y <= cr; y++) {
int thick = (y % c ? 0 : 1);
draw_rect(fe, BORDER-1, BORDER + y*TILE_SIZE - thick,
cr*TILE_SIZE+3, 1+2*thick, COL_GRID);
}
}
/*
* Draw any numbers which need redrawing.
*/
for (x = 0; x < cr; x++) {
for (y = 0; y < cr; y++) {
draw_number(fe, ds, state, x, y,
(x == ui->hx && y == ui->hy) ||
(flashtime > 0 &&
(flashtime <= FLASH_TIME/3 ||
flashtime >= FLASH_TIME*2/3)));
}
}
/*
* Update the _entire_ grid if necessary.
*/
if (!ds->started) {
draw_update(fe, 0, 0, XSIZE(cr), YSIZE(cr));
ds->started = TRUE;
}
}
static float game_anim_length(game_state *oldstate, game_state *newstate,
int dir)
{
return 0.0F;
}
static float game_flash_length(game_state *oldstate, game_state *newstate,
int dir)
{
if (!oldstate->completed && newstate->completed)
return FLASH_TIME;
return 0.0F;
}
static int game_wants_statusbar(void)
{
return FALSE;
}
#ifdef COMBINED
#define thegame solo
#endif
const struct game thegame = {
"Solo", "games.solo", TRUE,
default_params,
game_fetch_preset,
decode_params,
encode_params,
free_params,
dup_params,
game_configure,
custom_params,
validate_params,
new_game_seed,
validate_seed,
new_game,
dup_game,
free_game,
new_ui,
free_ui,
make_move,
game_size,
game_colours,
game_new_drawstate,
game_free_drawstate,
game_redraw,
game_anim_length,
game_flash_length,
game_wants_statusbar,
};
#ifdef STANDALONE_SOLVER
void frontend_default_colour(frontend *fe, float *output) {}
void draw_text(frontend *fe, int x, int y, int fonttype, int fontsize,
int align, int colour, char *text) {}
void draw_rect(frontend *fe, int x, int y, int w, int h, int colour) {}
void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour) {}
void draw_polygon(frontend *fe, int *coords, int npoints,
int fill, int colour) {}
void clip(frontend *fe, int x, int y, int w, int h) {}
void unclip(frontend *fe) {}
void start_draw(frontend *fe) {}
void draw_update(frontend *fe, int x, int y, int w, int h) {}
void end_draw(frontend *fe) {}
#include <stdarg.h>
void fatal(char *fmt, ...)
{
va_list ap;
fprintf(stderr, "fatal error: ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fprintf(stderr, "\n");
exit(1);
}
int main(int argc, char **argv)
{
game_params *p;
game_state *s;
int recurse = FALSE;
char *id = NULL, *seed, *err;
int y, x;
while (--argc > 0) {
char *p = *++argv;
if (!strcmp(p, "-r")) {
recurse = TRUE;
} else if (!strcmp(p, "-n")) {
recurse = FALSE;
} else if (*p == '-') {
fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0]);
return 1;
} else {
id = p;
}
}
if (!id) {
fprintf(stderr, "usage: %s [-n | -r] <game_id>\n", argv[0]);
return 1;
}
seed = strchr(id, ':');
if (!seed) {
fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]);
return 1;
}
*seed++ = '\0';
p = decode_params(id);
err = validate_seed(p, seed);
if (err) {
fprintf(stderr, "%s: %s\n", argv[0], err);
return 1;
}
s = new_game(p, seed);
if (recurse) {
int ret = rsolve(p->c, p->r, s->grid, NULL, 2);
if (ret > 1) {
printf("multiple solutions detected; only first one output\n");
}
} else {
nsolve(p->c, p->r, s->grid);
}
for (y = 0; y < p->c * p->r; y++) {
for (x = 0; x < p->c * p->r; x++) {
printf("%2.0d", s->grid[y * p->c * p->r + x]);
}
printf("\n");
}
printf("\n");
return 0;
}
#endif