*
* TODO:
*
- * - my technique for highlighting errors in the tent/tree matching
- * is not perfect. It currently works by finding the connected
- * components of the bipartite adjacency graph between tents and
- * trees, and highlighting red all the tents in such a component
- * if they outnumber the trees (the red meaning "these tents have
- * too few trees between them") and vice versa if the trees
- * outnumber the tents (but this time considering BLANKs as
- * potential tents as yet unplaced, to avoid highlighting
- * 'errors' from the word go before the player has actually made
- * any mistake). However, something more subtle can go wrong
- * within a component: consider, for instance, the setup
- *
- * T
- * tTtT
- * t
- *
- * in which there is one connected component containing equal
- * numbers of trees and tents, but nonetheless there is no
- * perfect matching that can link the two sensibly. This will be
- * rejected by the rigorous solution checker, but the error
- * highlighter won't currently spot it.
- *
- * Well, the _matching_ error highlighter won't spot it, anyway.
- * In that diagram, there are two pairs of diagonally adjacent
- * tents, which will be flagged as erroneous because that's much
- * easier. So if I could prove that _all_ such setups require
- * diagonally adjacent tents, I could safely ignore this problem.
- * If not, however, then a proper treatment will require running
- * the maxflow matcher over each component once I've identified
- * them.
- *
* - it might be nice to make setter-provided tent/nontent clues
* inviolable?
* * on the other hand, this would introduce considerable extra
sfree(params);
}
-static game_params *dup_params(game_params *params)
+static game_params *dup_params(const game_params *params)
{
game_params *ret = snew(game_params);
*ret = *params; /* structure copy */
}
}
-static char *encode_params(game_params *params, int full)
+static char *encode_params(const game_params *params, int full)
{
char buf[120];
return dupstr(buf);
}
-static config_item *game_configure(game_params *params)
+static config_item *game_configure(const game_params *params)
{
config_item *ret;
char buf[80];
return ret;
}
-static game_params *custom_params(config_item *cfg)
+static game_params *custom_params(const config_item *cfg)
{
game_params *ret = snew(game_params);
return ret;
}
-static char *validate_params(game_params *params, int full)
+static char *validate_params(const game_params *params, int full)
{
/*
* Generating anything under 4x4 runs into trouble of one kind
char *soln, struct solver_scratch *sc, int diff)
{
int x, y, d, i, j;
- char *mrow, *mrow1, *mrow2, *trow, *trow1, *trow2;
+ char *mrow, *trow, *trow1, *trow2;
/*
* Set up solver data.
* hasn't been set up yet.
*/
mrow = sc->mrows;
- mrow1 = sc->mrows + len;
- mrow2 = sc->mrows + 2*len;
trow = sc->trows;
trow1 = sc->trows + len;
trow2 = sc->trows + 2*len;
return 1;
}
-static char *new_game_desc(game_params *params, random_state *rs,
+static char *new_game_desc(const game_params *params_in, random_state *rs,
char **aux, int interactive)
{
+ game_params params_copy = *params_in; /* structure copy */
+ game_params *params = ¶ms_copy;
int w = params->w, h = params->h;
int ntrees = w * h / 5;
char *grid = snewn(w*h, char);
j = maxflow(w*h+2, w*h+1, w*h, nedges, edges, capacity, flow, NULL);
if (j < ntrees)
- continue; /* couldn't place all the tents */
+ continue; /* couldn't place all the trees */
/*
* We've placed the trees. Now we need to work out _where_
return ret;
}
-static char *validate_desc(game_params *params, char *desc)
+static char *validate_desc(const game_params *params, const char *desc)
{
int w = params->w, h = params->h;
int area, i;
desc++;
}
+ if (area < w * h + 1)
+ return "Not enough data to fill grid";
+ else if (area > w * h + 1)
+ return "Too much data to fill grid";
for (i = 0; i < w+h; i++) {
if (!*desc)
return NULL;
}
-static game_state *new_game(midend *me, game_params *params, char *desc)
+static game_state *new_game(midend *me, const game_params *params,
+ const char *desc)
{
int w = params->w, h = params->h;
game_state *state = snew(game_state);
return state;
}
-static game_state *dup_game(game_state *state)
+static game_state *dup_game(const game_state *state)
{
int w = state->p.w, h = state->p.h;
game_state *ret = snew(game_state);
sfree(state);
}
-static char *solve_game(game_state *state, game_state *currstate,
- char *aux, char **error)
+static char *solve_game(const game_state *state, const game_state *currstate,
+ const char *aux, char **error)
{
int w = state->p.w, h = state->p.h;
}
}
-static int game_can_format_as_text_now(game_params *params)
+static int game_can_format_as_text_now(const game_params *params)
{
- return TRUE;
+ return params->w <= 1998 && params->h <= 1998; /* 999 tents */
}
-static char *game_text_format(game_state *state)
+static char *game_text_format(const game_state *state)
{
- int w = state->p.w, h = state->p.h;
- char *ret, *p;
- int x, y;
+ int w = state->p.w, h = state->p.h, r, c;
+ int cw = 4, ch = 2, gw = (w+1)*cw + 2, gh = (h+1)*ch + 1, len = gw * gh;
+ char *board = snewn(len + 1, char);
+
+ sprintf(board, "%*s\n", len - 2, "");
+ for (r = 0; r <= h; ++r) {
+ for (c = 0; c <= w; ++c) {
+ int cell = r*ch*gw + cw*c, center = cell + gw*ch/2 + cw/2;
+ int i = r*w + c, n = 1000;
+
+ if (r == h && c == w) /* NOP */;
+ else if (c == w) n = state->numbers->numbers[w + r];
+ else if (r == h) n = state->numbers->numbers[c];
+ else switch (state->grid[i]) {
+ case BLANK: board[center] = '.'; break;
+ case TREE: board[center] = 'T'; break;
+ case TENT: memcpy(board + center - 1, "//\\", 3); break;
+ case NONTENT: break;
+ default: memcpy(board + center - 1, "wtf", 3);
+ }
- /*
- * FIXME: We currently do not print the numbers round the edges
- * of the grid. I need to work out a sensible way of doing this
- * even when the column numbers exceed 9.
- *
- * In the absence of those numbers, the result size is h lines
- * of w+1 characters each, plus a NUL.
- *
- * This function is currently only used by the standalone
- * solver; until I make it look more sensible, I won't enable
- * it in the main game structure.
- */
- ret = snewn(h*(w+1) + 1, char);
- p = ret;
- for (y = 0; y < h; y++) {
- for (x = 0; x < w; x++) {
- *p = (state->grid[y*w+x] == BLANK ? '.' :
- state->grid[y*w+x] == TREE ? 'T' :
- state->grid[y*w+x] == TENT ? '*' :
- state->grid[y*w+x] == NONTENT ? '-' : '?');
- p++;
+ if (n < 100) {
+ board[center] = '0' + n % 10;
+ if (n >= 10) board[center - 1] = '0' + n / 10;
+ } else if (n < 1000) {
+ board[center + 1] = '0' + n % 10;
+ board[center] = '0' + n / 10 % 10;
+ board[center - 1] = '0' + n / 100;
+ }
+
+ board[cell] = '+';
+ memset(board + cell + 1, '-', cw - 1);
+ for (i = 1; i < ch; ++i) board[cell + i*gw] = '|';
+ }
+
+ for (c = 0; c < ch; ++c) {
+ board[(r*ch+c)*gw + gw - 2] =
+ c == 0 ? '+' : r < h ? '|' : ' ';
+ board[(r*ch+c)*gw + gw - 1] = '\n';
}
- *p++ = '\n';
}
- *p++ = '\0';
- return ret;
+ memset(board + len - gw, '-', gw - 2 - cw);
+ for (c = 0; c <= w; ++c) board[len - gw + cw*c] = '+';
+
+ return board;
}
struct game_ui {
int cx, cy, cdisp; /* cursor position, and ?display. */
};
-static game_ui *new_ui(game_state *state)
+static game_ui *new_ui(const game_state *state)
{
game_ui *ui = snew(game_ui);
ui->dsx = ui->dsy = -1;
sfree(ui);
}
-static char *encode_ui(game_ui *ui)
+static char *encode_ui(const game_ui *ui)
{
return NULL;
}
-static void decode_ui(game_ui *ui, char *encoding)
+static void decode_ui(game_ui *ui, const char *encoding)
{
}
-static void game_changed_state(game_ui *ui, game_state *oldstate,
- game_state *newstate)
+static void game_changed_state(game_ui *ui, const game_state *oldstate,
+ const game_state *newstate)
{
}
#define FLASH_TIME 0.30F
-static int drag_xform(game_ui *ui, int x, int y, int v)
+static int drag_xform(const game_ui *ui, int x, int y, int v)
{
int xmin, ymin, xmax, ymax;
ymin = min(ui->dsy, ui->dey);
ymax = max(ui->dsy, ui->dey);
+#ifndef STYLUS_BASED
/*
* Left-dragging has no effect, so we treat a left-drag as a
* single click on dsx,dsy.
xmin = xmax = ui->dsx;
ymin = ymax = ui->dsy;
}
+#endif
if (x < xmin || x > xmax || y < ymin || y > ymax)
return v; /* no change outside drag area */
* Results of a simple click. Left button sets blanks to
* tents; right button sets blanks to non-tents; either
* button clears a non-blank square.
+ * If stylus-based however, it loops instead.
*/
if (ui->drag_button == LEFT_BUTTON)
+#ifdef STYLUS_BASED
+ v = (v == BLANK ? TENT : (v == TENT ? NONTENT : BLANK));
+ else
+ v = (v == BLANK ? NONTENT : (v == NONTENT ? TENT : BLANK));
+#else
v = (v == BLANK ? TENT : BLANK);
else
v = (v == BLANK ? NONTENT : BLANK);
+#endif
} else {
/*
* Results of a drag. Left-dragging has no effect.
if (ui->drag_button == RIGHT_BUTTON)
v = (v == BLANK ? NONTENT : v);
else
+#ifdef STYLUS_BASED
+ v = (v == BLANK ? NONTENT : v);
+#else
/* do nothing */;
+#endif
}
return v;
}
-static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
- int x, int y, int button)
+static char *interpret_move(const game_state *state, game_ui *ui,
+ const game_drawstate *ds,
+ int x, int y, int button)
{
int w = state->p.w, h = state->p.h;
char tmpbuf[80];
+ int shift = button & MOD_SHFT, control = button & MOD_CTRL;
+
+ button &= ~MOD_MASK;
if (button == LEFT_BUTTON || button == RIGHT_BUTTON) {
x = FROMCOORD(x);
}
if (IS_CURSOR_MOVE(button)) {
- move_cursor(button, &ui->cx, &ui->cy, w, h, 0);
ui->cdisp = 1;
+ if (shift || control) {
+ int len = 0, i, indices[2];
+ indices[0] = ui->cx + w * ui->cy;
+ move_cursor(button, &ui->cx, &ui->cy, w, h, 0);
+ indices[1] = ui->cx + w * ui->cy;
+
+ /* NONTENTify all unique traversed eligible squares */
+ for (i = 0; i <= (indices[0] != indices[1]); ++i)
+ if (state->grid[indices[i]] == BLANK ||
+ (control && state->grid[indices[i]] == TENT)) {
+ len += sprintf(tmpbuf + len, "%sN%d,%d", len ? ";" : "",
+ indices[i] % w, indices[i] / w);
+ assert(len < lenof(tmpbuf));
+ }
+
+ tmpbuf[len] = '\0';
+ if (len) return dupstr(tmpbuf);
+ } else
+ move_cursor(button, &ui->cx, &ui->cy, w, h, 0);
return "";
}
if (ui->cdisp) {
return NULL;
}
-static game_state *execute_move(game_state *state, char *move)
+static game_state *execute_move(const game_state *state, const char *move)
{
int w = state->p.w, h = state->p.h;
char c;
* Drawing routines.
*/
-static void game_compute_size(game_params *params, int tilesize,
- int *x, int *y)
+static void game_compute_size(const game_params *params, int tilesize,
+ int *x, int *y)
{
/* fool the macros */
struct dummy { int tilesize; } dummy, *ds = &dummy;
}
static void game_set_size(drawing *dr, game_drawstate *ds,
- game_params *params, int tilesize)
+ const game_params *params, int tilesize)
{
ds->tilesize = tilesize;
}
return ret;
}
-static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
+static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state)
{
int w = state->p.w, h = state->p.h;
struct game_drawstate *ds = snew(struct game_drawstate);
ERR_OVERCOMMITTED
};
-static int *find_errors(game_state *state, char *grid)
+static int *find_errors(const game_state *state, char *grid)
{
int w = state->p.w, h = state->p.h;
int *ret = snewn(w*h + w + h, int);
int *tmp = snewn(w*h*2, int), *dsf = tmp + w*h;
int x, y;
+ /*
+ * This function goes through a grid and works out where to
+ * highlight play errors in red. The aim is that it should
+ * produce at least one error highlight for any complete grid
+ * (or complete piece of grid) violating a puzzle constraint, so
+ * that a grid containing no BLANK squares is either a win or is
+ * marked up in some way that indicates why not.
+ *
+ * So it's easy enough to highlight errors in the numeric clues
+ * - just light up any row or column number which is not
+ * fulfilled - and it's just as easy to highlight adjacent
+ * tents. The difficult bit is highlighting failures in the
+ * tent/tree matching criterion.
+ *
+ * A natural approach would seem to be to apply the maxflow
+ * algorithm to find the tent/tree matching; if this fails, it
+ * must necessarily terminate with a min-cut which can be
+ * reinterpreted as some set of trees which have too few tents
+ * between them (or vice versa). However, it's bad for
+ * localising errors, because it's not easy to make the
+ * algorithm narrow down to the _smallest_ such set of trees: if
+ * trees A and B have only one tent between them, for instance,
+ * it might perfectly well highlight not only A and B but also
+ * trees C and D which are correctly matched on the far side of
+ * the grid, on the grounds that those four trees between them
+ * have only three tents.
+ *
+ * Also, that approach fares badly when you introduce the
+ * additional requirement that incomplete grids should have
+ * errors highlighted only when they can be proved to be errors
+ * - so that trees should not be marked as having too few tents
+ * if there are enough BLANK squares remaining around them that
+ * could be turned into the missing tents (to do so would be
+ * patronising, since the overwhelming likelihood is not that
+ * the player has forgotten to put a tree there but that they
+ * have merely not put one there _yet_). However, tents with too
+ * few trees can be marked immediately, since those are
+ * definitely player error.
+ *
+ * So I adopt an alternative approach, which is to consider the
+ * bipartite adjacency graph between trees and tents
+ * ('bipartite' in the sense that for these purposes I
+ * deliberately ignore two adjacent trees or two adjacent
+ * tents), divide that graph up into its connected components
+ * using a dsf, and look for components which contain different
+ * numbers of trees and tents. This allows me to highlight
+ * groups of tents with too few trees between them immediately,
+ * and then in order to find groups of trees with too few tents
+ * I redo the same process but counting BLANKs as potential
+ * tents (so that the only trees highlighted are those
+ * surrounded by enough NONTENTs to make it impossible to give
+ * them enough tents).
+ *
+ * However, this technique is incomplete: it is not a sufficient
+ * condition for the existence of a perfect matching that every
+ * connected component of the graph has the same number of tents
+ * and trees. An example of a graph which satisfies the latter
+ * condition but still has no perfect matching is
+ *
+ * A B C
+ * | / ,/|
+ * | / ,'/ |
+ * | / ,' / |
+ * |/,' / |
+ * 1 2 3
+ *
+ * which can be realised in Tents as
+ *
+ * B
+ * A 1 C 2
+ * 3
+ *
+ * The matching-error highlighter described above will not mark
+ * this construction as erroneous. However, something else will:
+ * the three tents in the above diagram (let us suppose A,B,C
+ * are the tents, though it doesn't matter which) contain two
+ * diagonally adjacent pairs. So there will be _an_ error
+ * highlighted for the above layout, even though not all types
+ * of error will be highlighted.
+ *
+ * And in fact we can prove that this will always be the case:
+ * that the shortcomings of the matching-error highlighter will
+ * always be made up for by the easy tent adjacency highlighter.
+ *
+ * Lemma: Let G be a bipartite graph between n trees and n
+ * tents, which is connected, and in which no tree has degree
+ * more than two (but a tent may). Then G has a perfect matching.
+ *
+ * (Note: in the statement and proof of the Lemma I will
+ * consistently use 'tree' to indicate a type of graph vertex as
+ * opposed to a tent, and not to indicate a tree in the graph-
+ * theoretic sense.)
+ *
+ * Proof:
+ *
+ * If we can find a tent of degree 1 joined to a tree of degree
+ * 2, then any perfect matching must pair that tent with that
+ * tree. Hence, we can remove both, leaving a smaller graph G'
+ * which still satisfies all the conditions of the Lemma, and
+ * which has a perfect matching iff G does.
+ *
+ * So, wlog, we may assume G contains no tent of degree 1 joined
+ * to a tree of degree 2; if it does, we can reduce it as above.
+ *
+ * If G has no tent of degree 1 at all, then every tent has
+ * degree at least two, so there are at least 2n edges in the
+ * graph. But every tree has degree at most two, so there are at
+ * most 2n edges. Hence there must be exactly 2n edges, so every
+ * tree and every tent must have degree exactly two, which means
+ * that the whole graph consists of a single loop (by
+ * connectedness), and therefore certainly has a perfect
+ * matching.
+ *
+ * Alternatively, if G does have a tent of degree 1 but it is
+ * not connected to a tree of degree 2, then the tree it is
+ * connected to must have degree 1 - and, by connectedness, that
+ * must mean that that tent and that tree between them form the
+ * entire graph. This trivial graph has a trivial perfect
+ * matching. []
+ *
+ * That proves the lemma. Hence, in any case where the matching-
+ * error highlighter fails to highlight an erroneous component
+ * (because it has the same number of tents as trees, but they
+ * cannot be matched up), the above lemma tells us that there
+ * must be a tree with degree more than 2, i.e. a tree
+ * orthogonally adjacent to at least three tents. But in that
+ * case, there must be some pair of those three tents which are
+ * diagonally adjacent to each other, so the tent-adjacency
+ * highlighter will necessarily show an error. So any filled
+ * layout in Tents which is not a correct solution to the puzzle
+ * must have _some_ error highlighted by the subroutine below.
+ *
+ * (Of course it would be nicer if we could highlight all
+ * errors: in the above example layout, we would like to
+ * highlight tents A,B as having too few trees between them, and
+ * trees 2,3 as having too few tents, in addition to marking the
+ * adjacency problems. But I can't immediately think of any way
+ * to find the smallest sets of such tents and trees without an
+ * O(2^N) loop over all subsets of a given component.)
+ */
+
/*
* ret[0] through to ret[w*h-1] give error markers for the grid
* squares. After that, ret[w*h] to ret[w*h+w-1] give error
/*
* Internal redraw function, used for printing as well as drawing.
*/
-static void int_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
- game_state *state, int dir, game_ui *ui,
+static void int_redraw(drawing *dr, game_drawstate *ds,
+ const game_state *oldstate, const game_state *state,
+ int dir, const game_ui *ui,
float animtime, float flashtime, int printing)
{
int w = state->p.w, h = state->p.h;
* currently active drag: we transform dsx,dsy but not anything
* else. (This seems to strike a good compromise between having
* the error highlights respond instantly to single clicks, but
- * not give constant feedback during a right-drag.)
+ * not giving constant feedback during a right-drag.)
*/
if (ui && ui->drag_button >= 0) {
tmpgrid = snewn(w*h, char);
* changed) the numbers.
*/
for (x = 0; x < w; x++) {
- if (ds->numbersdrawn[x] != errors[w*h+x]) {
+ if (printing || ds->numbersdrawn[x] != errors[w*h+x]) {
char buf[80];
draw_rect(dr, COORD(x), COORD(h)+1, TILESIZE, BRBORDER-1,
COL_BACKGROUND);
FONT_VARIABLE, TILESIZE/2, ALIGN_HCENTRE|ALIGN_VNORMAL,
(errors[w*h+x] ? COL_ERROR : COL_GRID), buf);
draw_update(dr, COORD(x), COORD(h)+1, TILESIZE, BRBORDER-1);
- ds->numbersdrawn[x] = errors[w*h+x];
+ if (!printing)
+ ds->numbersdrawn[x] = errors[w*h+x];
}
}
for (y = 0; y < h; y++) {
- if (ds->numbersdrawn[w+y] != errors[w*h+w+y]) {
+ if (printing || ds->numbersdrawn[w+y] != errors[w*h+w+y]) {
char buf[80];
draw_rect(dr, COORD(w)+1, COORD(y), BRBORDER-1, TILESIZE,
COL_BACKGROUND);
FONT_VARIABLE, TILESIZE/2, ALIGN_HRIGHT|ALIGN_VCENTRE,
(errors[w*h+w+y] ? COL_ERROR : COL_GRID), buf);
draw_update(dr, COORD(w)+1, COORD(y), BRBORDER-1, TILESIZE);
- ds->numbersdrawn[w+y] = errors[w*h+w+y];
+ if (!printing)
+ ds->numbersdrawn[w+y] = errors[w*h+w+y];
}
}
sfree(errors);
}
-static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
- game_state *state, int dir, game_ui *ui,
- float animtime, float flashtime)
+static void game_redraw(drawing *dr, game_drawstate *ds,
+ const game_state *oldstate, const game_state *state,
+ int dir, const game_ui *ui,
+ float animtime, float flashtime)
{
int_redraw(dr, ds, oldstate, state, dir, ui, animtime, flashtime, FALSE);
}
-static float game_anim_length(game_state *oldstate, game_state *newstate,
- int dir, game_ui *ui)
+static float game_anim_length(const game_state *oldstate,
+ const game_state *newstate, int dir, game_ui *ui)
{
return 0.0F;
}
-static float game_flash_length(game_state *oldstate, game_state *newstate,
- int dir, game_ui *ui)
+static float game_flash_length(const game_state *oldstate,
+ const game_state *newstate, int dir, game_ui *ui)
{
if (!oldstate->completed && newstate->completed &&
!oldstate->used_solve && !newstate->used_solve)
return 0.0F;
}
-static int game_timing_state(game_state *state, game_ui *ui)
+static int game_status(const game_state *state)
+{
+ return state->completed ? +1 : 0;
+}
+
+static int game_timing_state(const game_state *state, game_ui *ui)
{
return TRUE;
}
-static void game_print_size(game_params *params, float *x, float *y)
+static void game_print_size(const game_params *params, float *x, float *y)
{
int pw, ph;
*y = ph / 100.0F;
}
-static void game_print(drawing *dr, game_state *state, int tilesize)
+static void game_print(drawing *dr, const game_state *state, int tilesize)
{
int c;
const struct game thegame = {
"Tents", "games.tents", "tents",
default_params,
- game_fetch_preset,
+ game_fetch_preset, NULL,
decode_params,
encode_params,
free_params,
dup_game,
free_game,
TRUE, solve_game,
- FALSE, game_can_format_as_text_now, game_text_format,
+ TRUE, game_can_format_as_text_now, game_text_format,
new_ui,
free_ui,
encode_ui,
game_redraw,
game_anim_length,
game_flash_length,
+ game_status,
TRUE, FALSE, game_print_size, game_print,
FALSE, /* wants_statusbar */
FALSE, game_timing_state,