#define Y(state, i) ( (i) / (state)->w )
#define C(state, x, y) ( (y) * (state)->w + (x) )
+#define PARITY_P(params, gap) (((X((params), (gap)) - ((params)->w - 1)) ^ \
+ (Y((params), (gap)) - ((params)->h - 1)) ^ \
+ (((params)->w * (params)->h) + 1)) & 1)
+#define PARITY_S(state) PARITY_P((state), ((state)->gap_pos))
+
enum {
COL_BACKGROUND,
COL_TEXT,
* rather than 0,...,n-1; this is a cyclic permutation of
* the starting point and hence is odd iff n is even.)
*/
- parity = ((X(params, gap) - (params->w-1)) ^
- (Y(params, gap) - (params->h-1)) ^
- (n+1)) & 1;
+ parity = PARITY_P(params, gap);
/*
* Try the last two tiles one way round. If that fails, swap
int tilesize;
};
+static int flip_cursor(int button)
+{
+ switch (button) {
+ case CURSOR_UP: return CURSOR_DOWN;
+ case CURSOR_DOWN: return CURSOR_UP;
+ case CURSOR_LEFT: return CURSOR_RIGHT;
+ case CURSOR_RIGHT: return CURSOR_LEFT;
+ }
+ return 0;
+}
+
+static void next_move_3x2(int ax, int ay, int bx, int by,
+ int gx, int gy, int *dx, int *dy)
+{
+ /* When w = 3 and h = 2 and the tile going in the top left corner
+ * is at (ax, ay) and the tile going in the bottom left corner is
+ * at (bx, by) and the blank tile is at (gx, gy), how do you move? */
+
+ /* Hard-coded shortest solutions. Sorry. */
+ static const unsigned char move[120] = {
+ 1,2,0,1,2,2,
+ 2,0,0,2,0,0,
+ 0,0,2,0,2,0,
+ 0,0,0,2,0,2,
+ 2,0,0,0,2,0,
+
+ 0,3,0,1,1,1,
+ 3,0,3,2,1,2,
+ 2,1,1,0,1,0,
+ 2,1,2,1,0,1,
+ 1,2,0,2,1,2,
+
+ 0,1,3,1,3,0,
+ 1,3,1,3,0,3,
+ 0,0,3,3,0,0,
+ 0,0,0,1,2,1,
+ 3,0,0,1,1,1,
+
+ 3,1,1,1,3,0,
+ 1,1,1,1,1,1,
+ 1,3,1,1,3,0,
+ 1,1,3,3,1,3,
+ 1,3,0,0,0,0
+ };
+ static const struct { int dx, dy; } d[4] = {{+1,0},{-1,0},{0,+1},{0,-1}};
+
+ int ea = 3*ay + ax, eb = 3*by + bx, eg = 3*gy + gx, v;
+ if (eb > ea) --eb;
+ if (eg > ea) --eg;
+ if (eg > eb) --eg;
+ v = move[ea + eb*6 + eg*5*6];
+ *dx = d[v].dx;
+ *dy = d[v].dy;
+}
+
+static void next_move(int nx, int ny, int ox, int oy, int gx, int gy,
+ int tx, int ty, int w, int *dx, int *dy)
+{
+ const int to_tile_x = (gx < nx ? +1 : -1);
+ const int to_goal_x = (gx < tx ? +1 : -1);
+ const int gap_x_on_goal_side = ((nx-tx) * (nx-gx) > 0);
+
+ assert (nx != tx || ny != ty); /* not already in place */
+ assert (nx != gx || ny != gy); /* not placing the gap */
+ assert (ty <= ny); /* because we're greedy (and flipping) */
+ assert (ty <= gy); /* because we're greedy (and flipping) */
+
+ /* TODO: define a termination function. Idea: 0 if solved, or
+ * the number of moves to solve the next piece plus the number of
+ * further unsolved pieces times an upper bound on the number of
+ * moves required to solve any piece. If such a function can be
+ * found, we have (termination && (termination => correctness)).
+ * The catch is our temporary disturbance of 2x3 corners. */
+
+ /* handles end-of-row, when 3 and 4 are in the top right 2x3 box */
+ if (tx == w - 2 &&
+ ny <= ty + 2 && (nx == tx || nx == tx + 1) &&
+ oy <= ty + 2 && (ox == tx || ox == tx + 1) &&
+ gy <= ty + 2 && (gx == tx || gx == tx + 1))
+ {
+ next_move_3x2(oy - ty, tx + 1 - ox,
+ ny - ty, tx + 1 - nx,
+ gy - ty, tx + 1 - gx, dy, dx);
+ *dx *= -1;
+ return;
+ }
+
+ if (tx == w - 1) {
+ if (ny <= ty + 2 && (nx == tx || nx == tx - 1) &&
+ gy <= ty + 2 && (gx == tx || gx == tx - 1)) {
+ next_move_3x2(ny - ty, tx - nx, 0, 1, gy - ty, tx - gx, dy, dx);
+ *dx *= -1;
+ } else if (gy == ty)
+ *dy = +1;
+ else if (nx != tx || ny != ty + 1) {
+ next_move((w - 1) - nx, ny, -1, -1, (w - 1) - gx, gy,
+ 0, ty + 1, -1, dx, dy);
+ *dx *= -1;
+ } else if (gx == nx)
+ *dy = -1;
+ else
+ *dx = +1;
+ return;
+ }
+
+ /* note that *dy = -1 is unsafe when gy = ty + 1 and gx < tx */
+ if (gy < ny)
+ if (nx == gx || (gy == ty && gx == tx))
+ *dy = +1;
+ else if (!gap_x_on_goal_side)
+ *dx = to_tile_x;
+ else if (ny - ty > abs(nx - tx))
+ *dx = to_tile_x;
+ else *dy = +1;
+
+ else if (gy == ny)
+ if (nx == tx) /* then we know ny > ty */
+ if (gx > nx || ny > ty + 1)
+ *dy = -1; /* ... so this is safe */
+ else
+ *dy = +1;
+ else if (gap_x_on_goal_side)
+ *dx = to_tile_x;
+ else if (gy == ty || (gy == ty + 1 && gx < tx))
+ *dy = +1;
+ else
+ *dy = -1;
+
+ else if (nx == tx) /* gy > ny */
+ if (gx > nx)
+ *dy = -1;
+ else
+ *dx = +1;
+ else if (gx == nx)
+ *dx = to_goal_x;
+ else if (gap_x_on_goal_side)
+ if (gy == ty + 1 && gx < tx)
+ *dx = to_tile_x;
+ else
+ *dy = -1;
+
+ else if (ny - ty > abs(nx - tx))
+ *dy = -1;
+ else
+ *dx = to_tile_x;
+}
+
+static int compute_hint(const game_state *state, int *out_x, int *out_y)
+{
+ /* The overall solving process is this:
+ * 1. Find the next piece to be put in its place
+ * 2. Move it diagonally towards its place
+ * 3. Move it horizontally or vertically towards its place
+ * (Modulo the last two tiles at the end of each row/column)
+ */
+
+ int gx = X(state, state->gap_pos);
+ int gy = Y(state, state->gap_pos);
+
+ int tx, ty, nx, ny, ox, oy, /* {target,next,next2}_{x,y} */ i;
+ int dx = 0, dy = 0;
+
+ /* 1. Find the next piece
+ * if (there are no more unfinished columns than rows) {
+ * fill the top-most row, left to right
+ * } else { fill the left-most column, top to bottom }
+ */
+ const int w = state->w, h = state->h, n = w*h;
+ int next_piece = 0, next_piece_2 = 0, solr = 0, solc = 0;
+ int unsolved_rows = h, unsolved_cols = w;
+
+ assert(out_x);
+ assert(out_y);
+
+ while (solr < h && solc < w) {
+ int start, step, stop;
+ if (unsolved_cols <= unsolved_rows)
+ start = solr*w + solc, step = 1, stop = unsolved_cols;
+ else
+ start = solr*w + solc, step = w, stop = unsolved_rows;
+ for (i = 0; i < stop; ++i) {
+ const int j = start + i*step;
+ if (state->tiles[j] != j + 1) {
+ next_piece = j + 1;
+ next_piece_2 = next_piece + step;
+ break;
+ }
+ }
+ if (i < stop) break;
+
+ (unsolved_cols <= unsolved_rows)
+ ? (++solr, --unsolved_rows)
+ : (++solc, --unsolved_cols);
+ }
+
+ if (next_piece == n)
+ return FALSE;
+
+ /* 2, 3. Move the next piece towards its place */
+
+ /* gx, gy already set */
+ tx = X(state, next_piece - 1); /* where we're going */
+ ty = Y(state, next_piece - 1);
+ for (i = 0; i < n && state->tiles[i] != next_piece; ++i);
+ nx = X(state, i); /* where we're at */
+ ny = Y(state, i);
+ for (i = 0; i < n && state->tiles[i] != next_piece_2; ++i);
+ ox = X(state, i);
+ oy = Y(state, i);
+
+ if (unsolved_cols <= unsolved_rows)
+ next_move(nx, ny, ox, oy, gx, gy, tx, ty, w, &dx, &dy);
+ else
+ next_move(ny, nx, oy, ox, gy, gx, ty, tx, h, &dy, &dx);
+
+ assert (dx || dy);
+
+ *out_x = gx + dx;
+ *out_y = gy + dy;
+ return TRUE;
+}
+
static char *interpret_move(const game_state *state, game_ui *ui,
const game_drawstate *ds,
int x, int y, int button)
{
- int gx, gy, dx, dy;
+ int cx = X(state, state->gap_pos), nx = cx;
+ int cy = Y(state, state->gap_pos), ny = cy;
char buf[80];
button &= ~MOD_MASK;
- gx = X(state, state->gap_pos);
- gy = Y(state, state->gap_pos);
-
- if (button == CURSOR_RIGHT && gx > 0)
- dx = gx - 1, dy = gy;
- else if (button == CURSOR_LEFT && gx < state->w-1)
- dx = gx + 1, dy = gy;
- else if (button == CURSOR_DOWN && gy > 0)
- dy = gy - 1, dx = gx;
- else if (button == CURSOR_UP && gy < state->h-1)
- dy = gy + 1, dx = gx;
- else if (button == LEFT_BUTTON) {
- dx = FROMCOORD(x);
- dy = FROMCOORD(y);
- if (dx < 0 || dx >= state->w || dy < 0 || dy >= state->h)
+ if (button == LEFT_BUTTON) {
+ nx = FROMCOORD(x);
+ ny = FROMCOORD(y);
+ if (nx < 0 || nx >= state->w || ny < 0 || ny >= state->h)
return NULL; /* out of bounds */
- /*
- * Any click location should be equal to the gap location
- * in _precisely_ one coordinate.
- */
- if ((dx == gx && dy == gy) || (dx != gx && dy != gy))
- return NULL;
+ } else if (IS_CURSOR_MOVE(button)) {
+ static int invert_cursor = -1;
+ if (invert_cursor == -1) {
+ char *env = getenv("FIFTEEN_INVERT_CURSOR");
+ invert_cursor = (env && (env[0] == 'y' || env[0] == 'Y'));
+ }
+ button = flip_cursor(button); /* the default */
+ if (invert_cursor)
+ button = flip_cursor(button); /* undoes the first flip */
+ move_cursor(button, &nx, &ny, state->w, state->h, FALSE);
+ } else if ((button == 'h' || button == 'H') && !state->completed) {
+ if (!compute_hint(state, &nx, &ny))
+ return NULL; /* shouldn't happen, since ^^we^^checked^^ */
} else
return NULL; /* no move */
- sprintf(buf, "M%d,%d", dx, dy);
- return dupstr(buf);
+ /*
+ * Any click location should be equal to the gap location
+ * in _precisely_ one coordinate.
+ */
+ if ((cx == nx) ^ (cy == ny)) {
+ sprintf(buf, "M%d,%d", nx, ny);
+ return dupstr(buf);
+ }
+
+ return NULL;
}
static game_state *execute_move(const game_state *from, const char *move)
FALSE, game_timing_state,
0, /* flags */
};
+
+#ifdef STANDALONE_SOLVER
+
+int main(int argc, char **argv)
+{
+ game_params *params;
+ game_state *state;
+ char *id = NULL, *desc, *err;
+ int grade = FALSE;
+ char *progname = argv[0];
+
+ char buf[80];
+ int limit, x, y, solvable;
+
+ while (--argc > 0) {
+ char *p = *++argv;
+ if (!strcmp(p, "-v")) {
+ /* solver_show_working = TRUE; */
+ } else if (!strcmp(p, "-g")) {
+ grade = TRUE;
+ } else if (*p == '-') {
+ fprintf(stderr, "%s: unrecognised option `%s'\n", progname, 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';
+
+ params = default_params();
+ decode_params(params, id);
+ err = validate_desc(params, desc);
+ if (err) {
+ free_params(params);
+ fprintf(stderr, "%s: %s\n", argv[0], err);
+ return 1;
+ }
+
+ state = new_game(NULL, params, desc);
+ free_params(params);
+
+ solvable = (PARITY_S(state) == perm_parity(state->tiles, state->n));
+ if (grade || !solvable) {
+ free_game(state);
+ fputs(solvable ? "Game is solvable" : "Game is unsolvable",
+ grade ? stdout : stderr);
+ return !grade;
+ }
+
+ for (limit = 5 * state->n * state->n * state->n; limit; --limit) {
+ game_state *next_state;
+ if (!compute_hint(state, &x, &y)) {
+ fprintf(stderr, "couldn't compute next move while solving %s:%s",
+ id, desc);
+ return 1;
+ }
+ printf("Move the space to (%d, %d), moving %d into the space\n",
+ x + 1, y + 1, state->tiles[C(state, x, y)]);
+ sprintf(buf, "M%d,%d", x, y);
+ next_state = execute_move(state, buf);
+
+ free_game(state);
+ if (!next_state) {
+ fprintf(stderr, "invalid move when solving %s:%s\n", id, desc);
+ return 1;
+ }
+ state = next_state;
+ if (next_state->completed) {
+ free_game(state);
+ return 0;
+ }
+ }
+
+ free_game(state);
+ fprintf(stderr, "ran out of moves for %s:%s\n", id, desc);
+ return 1;
+}
+
+#endif
~ian / sgt-puzzles.git / blobdiff