ref: 6ada3841a176fcdb12b953af23c0aac40532d417
parent: 12def7ede2c9cee4f7a5ac37a60ee1a61cd5c24a
author: Simon Tatham <anakin@pobox.com>
date: Sat Aug 13 06:43:26 EDT 2005
New puzzle: `Map'. Vaguely original, for a change. (This puzzle is theoretically printable, but I haven't added it in print.py since there's rather a lot of painful processing required to get from the game ID to the puzzle's visual appearance. It probably won't become printable unless I get round to implementing a more integrated printing architecture.) [originally from svn r6186]
--- a/Recipe
+++ b/Recipe
@@ -22,10 +22,11 @@
PEGS = pegs tree234
UNTANGLE = untangle tree234
SLANT = slant dsf
+MAP = map dsf
ALL = list NET NETSLIDE cube fifteen sixteen rect pattern solo twiddle
+ MINES samegame FLIP guess PEGS dominosa UNTANGLE blackbox SLANT
- + lightup
+ + lightup MAP
net : [X] gtk COMMON NET
netslide : [X] gtk COMMON NETSLIDE
@@ -46,6 +47,7 @@
blackbox : [X] gtk COMMON blackbox
slant : [X] gtk COMMON SLANT
lightup : [X] gtk COMMON lightup
+map : [X] gtk COMMON MAP
# Auxiliary command-line programs.
solosolver : [U] solo[STANDALONE_SOLVER] malloc
@@ -79,6 +81,7 @@
blackbox : [G] WINDOWS COMMON blackbox
slant : [G] WINDOWS COMMON SLANT
lightup : [G] WINDOWS COMMON lightup
+map : [G] WINDOWS COMMON MAP
# Mac OS X unified application containing all the puzzles.
Puzzles : [MX] osx osx.icns osx-info.plist COMMON ALL
@@ -170,7 +173,8 @@
install:
for i in cube net netslide fifteen sixteen twiddle \
pattern rect solo mines samegame flip guess \
- pegs dominosa untangle blackbox slant lightup; do \
+ pegs dominosa untangle blackbox slant lightup \
+ map; do \
$(INSTALL_PROGRAM) -m 755 $$i $(DESTDIR)$(gamesdir)/$$i; \
done
!end
--- a/list.c
+++ b/list.c
@@ -24,6 +24,7 @@
extern const game flip;
extern const game guess;
extern const game lightup;
+extern const game map;
extern const game mines;
extern const game net;
extern const game netslide;
@@ -45,6 +46,7 @@
&flip,
&guess,
&lightup,
+ &map,
&mines,
&net,
&netslide,
--- /dev/null
+++ b/map.c
@@ -1,0 +1,2061 @@
+/*
+ * map.c: Game involving four-colouring a map.
+ */
+
+/*
+ * TODO:
+ *
+ * - error highlighting
+ * - clue marking
+ * - more solver brains?
+ * - better four-colouring algorithm?
+ * - pencil marks?
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <ctype.h>
+#include <math.h>
+
+#include "puzzles.h"
+
+/*
+ * I don't seriously anticipate wanting to change the number of
+ * colours used in this game, but it doesn't cost much to use a
+ * #define just in case :-)
+ */
+#define FOUR 4
+#define THREE (FOUR-1)
+#define FIVE (FOUR+1)
+#define SIX (FOUR+2)
+
+/*
+ * Ghastly run-time configuration option, just for Gareth (again).
+ */
+static int flash_type = -1;
+static float flash_length;
+
+/*
+ * 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)
+#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) DIFFCOUNT };+static char const *const map_diffnames[] = { DIFFLIST(TITLE) };+static char const map_diffchars[] = DIFFLIST(ENCODE);
+#define DIFFCONFIG DIFFLIST(CONFIG)
+
+enum { TE, BE, LE, RE }; /* top/bottom/left/right edges */+
+enum {+ COL_BACKGROUND,
+ COL_GRID,
+ COL_0, COL_1, COL_2, COL_3,
+ NCOLOURS
+};
+
+struct game_params {+ int w, h, n, diff;
+};
+
+struct map {+ int refcount;
+ int *map;
+ int *graph;
+ int n;
+ int ngraph;
+ int *immutable;
+};
+
+struct game_state {+ game_params p;
+ struct map *map;
+ int *colouring;
+ int completed, cheated;
+};
+
+static game_params *default_params(void)
+{+ game_params *ret = snew(game_params);
+
+ ret->w = 20;
+ ret->h = 15;
+ ret->n = 30;
+ ret->diff = DIFF_NORMAL;
+
+ return ret;
+}
+
+static const struct game_params map_presets[] = {+ {20, 15, 30, DIFF_EASY},+ {20, 15, 30, DIFF_NORMAL},+ {30, 25, 75, DIFF_NORMAL},+};
+
+static int game_fetch_preset(int i, char **name, game_params **params)
+{+ game_params *ret;
+ char str[80];
+
+ if (i < 0 || i >= lenof(map_presets))
+ return FALSE;
+
+ ret = snew(game_params);
+ *ret = map_presets[i];
+
+ sprintf(str, "%dx%d, %d regions, %s", ret->w, ret->h, ret->n,
+ map_diffnames[ret->diff]);
+
+ *name = dupstr(str);
+ *params = ret;
+ 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 void decode_params(game_params *params, char const *string)
+{+ char const *p = string;
+
+ params->w = atoi(p);
+ while (*p && isdigit((unsigned char)*p)) p++;
+ if (*p == 'x') {+ p++;
+ params->h = atoi(p);
+ while (*p && isdigit((unsigned char)*p)) p++;
+ } else {+ params->h = params->w;
+ }
+ if (*p == 'n') {+ p++;
+ params->n = atoi(p);
+ while (*p && (*p == '.' || isdigit((unsigned char)*p))) p++;
+ } else {+ params->n = params->w * params->h / 8;
+ }
+ if (*p == 'd') {+ int i;
+ p++;
+ for (i = 0; i < DIFFCOUNT; i++)
+ if (*p == map_diffchars[i])
+ params->diff = i;
+ if (*p) p++;
+ }
+}
+
+static char *encode_params(game_params *params, int full)
+{+ char ret[400];
+
+ sprintf(ret, "%dx%dn%d", params->w, params->h, params->n);
+ if (full)
+ sprintf(ret + strlen(ret), "d%c", map_diffchars[params->diff]);
+
+ return dupstr(ret);
+}
+
+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 = "Regions";
+ ret[2].type = C_STRING;
+ sprintf(buf, "%d", params->n);
+ ret[2].sval = dupstr(buf);
+ ret[2].ival = 0;
+
+ 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->n = atoi(cfg[2].sval);
+ ret->diff = cfg[3].ival;
+
+ return ret;
+}
+
+static char *validate_params(game_params *params, int full)
+{+ if (params->w < 2 || params->h < 2)
+ return "Width and height must be at least two";
+ if (params->n < 5)
+ return "Must have at least five regions";
+ if (params->n > params->w * params->h)
+ return "Too many regions to fit in grid";
+ return NULL;
+}
+
+/* ----------------------------------------------------------------------
+ * Cumulative frequency table functions.
+ */
+
+/*
+ * Initialise a cumulative frequency table. (Hardly worth writing
+ * this function; all it does is to initialise everything in the
+ * array to zero.)
+ */
+static void cf_init(int *table, int n)
+{+ int i;
+
+ for (i = 0; i < n; i++)
+ table[i] = 0;
+}
+
+/*
+ * Increment the count of symbol `sym' by `count'.
+ */
+static void cf_add(int *table, int n, int sym, int count)
+{+ int bit;
+
+ bit = 1;
+ while (sym != 0) {+ if (sym & bit) {+ table[sym] += count;
+ sym &= ~bit;
+ }
+ bit <<= 1;
+ }
+
+ table[0] += count;
+}
+
+/*
+ * Cumulative frequency lookup: return the total count of symbols
+ * with value less than `sym'.
+ */
+static int cf_clookup(int *table, int n, int sym)
+{+ int bit, index, limit, count;
+
+ if (sym == 0)
+ return 0;
+
+ assert(0 < sym && sym <= n);
+
+ count = table[0]; /* start with the whole table size */
+
+ bit = 1;
+ while (bit < n)
+ bit <<= 1;
+
+ limit = n;
+
+ while (bit > 0) {+ /*
+ * Find the least number with its lowest set bit in this
+ * position which is greater than or equal to sym.
+ */
+ index = ((sym + bit - 1) &~ (bit * 2 - 1)) + bit;
+
+ if (index < limit) {+ count -= table[index];
+ limit = index;
+ }
+
+ bit >>= 1;
+ }
+
+ return count;
+}
+
+/*
+ * Single frequency lookup: return the count of symbol `sym'.
+ */
+static int cf_slookup(int *table, int n, int sym)
+{+ int count, bit;
+
+ assert(0 <= sym && sym < n);
+
+ count = table[sym];
+
+ for (bit = 1; sym+bit < n && !(sym & bit); bit <<= 1)
+ count -= table[sym+bit];
+
+ return count;
+}
+
+/*
+ * Return the largest symbol index such that the cumulative
+ * frequency up to that symbol is less than _or equal to_ count.
+ */
+static int cf_whichsym(int *table, int n, int count) {+ int bit, sym, top;
+
+ assert(count >= 0 && count < table[0]);
+
+ bit = 1;
+ while (bit < n)
+ bit <<= 1;
+
+ sym = 0;
+ top = table[0];
+
+ while (bit > 0) {+ if (sym+bit < n) {+ if (count >= top - table[sym+bit])
+ sym += bit;
+ else
+ top -= table[sym+bit];
+ }
+
+ bit >>= 1;
+ }
+
+ return sym;
+}
+
+/* ----------------------------------------------------------------------
+ * Map generation.
+ *
+ * FIXME: this isn't entirely optimal at present, because it
+ * inherently prioritises growing the largest region since there
+ * are more squares adjacent to it. This acts as a destabilising
+ * influence leading to a few large regions and mostly small ones.
+ * It might be better to do it some other way.
+ */
+
+#define WEIGHT_INCREASED 2 /* for increased perimeter */
+#define WEIGHT_DECREASED 4 /* for decreased perimeter */
+#define WEIGHT_UNCHANGED 3 /* for unchanged perimeter */
+
+/*
+ * Look at a square and decide which colours can be extended into
+ * it.
+ *
+ * If called with index < 0, it adds together one of
+ * WEIGHT_INCREASED, WEIGHT_DECREASED or WEIGHT_UNCHANGED for each
+ * colour that has a valid extension (according to the effect that
+ * it would have on the perimeter of the region being extended) and
+ * returns the overall total.
+ *
+ * If called with index >= 0, it returns one of the possible
+ * colours depending on the value of index, in such a way that the
+ * number of possible inputs which would give rise to a given
+ * return value correspond to the weight of that value.
+ */
+static int extend_options(int w, int h, int n, int *map,
+ int x, int y, int index)
+{+ int c, i, dx, dy;
+ int col[8];
+ int total = 0;
+
+ if (map[y*w+x] >= 0) {+ assert(index < 0);
+ return 0; /* can't do this square at all */
+ }
+
+ /*
+ * Fetch the eight neighbours of this square, in order around
+ * the square.
+ */
+ for (dy = -1; dy <= +1; dy++)
+ for (dx = -1; dx <= +1; dx++) {+ int index = (dy < 0 ? 6-dx : dy > 0 ? 2+dx : 2*(1+dx));
+ if (x+dx >= 0 && x+dx < w && y+dy >= 0 && y+dy < h)
+ col[index] = map[(y+dy)*w+(x+dx)];
+ else
+ col[index] = -1;
+ }
+
+ /*
+ * Iterate over each colour that might be feasible.
+ *
+ * FIXME: this routine currently has O(n) running time. We
+ * could turn it into O(FOUR) by only bothering to iterate over
+ * the colours mentioned in the four neighbouring squares.
+ */
+
+ for (c = 0; c < n; c++) {+ int count, neighbours, runs;
+
+ /*
+ * One of the even indices of col (representing the
+ * orthogonal neighbours of this square) must be equal to
+ * c, or else this square is not adjacent to region c and
+ * obviously cannot become an extension of it at this time.
+ */
+ neighbours = 0;
+ for (i = 0; i < 8; i += 2)
+ if (col[i] == c)
+ neighbours++;
+ if (!neighbours)
+ continue;
+
+ /*
+ * Now we know this square is adjacent to region c. The
+ * next question is, would extending it cause the region to
+ * become non-simply-connected? If so, we mustn't do it.
+ *
+ * We determine this by looking around col to see if we can
+ * find more than one separate run of colour c.
+ */
+ runs = 0;
+ for (i = 0; i < 8; i++)
+ if (col[i] == c && col[(i+1) & 7] != c)
+ runs++;
+ if (runs > 1)
+ continue;
+
+ assert(runs == 1);
+
+ /*
+ * This square is a possibility. Determine its effect on
+ * the region's perimeter (computed from the number of
+ * orthogonal neighbours - 1 means a perimeter increase, 3
+ * a decrease, 2 no change; 4 is impossible because the
+ * region would already not be simply connected) and we're
+ * done.
+ */
+ assert(neighbours > 0 && neighbours < 4);
+ count = (neighbours == 1 ? WEIGHT_INCREASED :
+ neighbours == 2 ? WEIGHT_UNCHANGED : WEIGHT_DECREASED);
+
+ total += count;
+ if (index >= 0 && index < count)
+ return c;
+ else
+ index -= count;
+ }
+
+ assert(index < 0);
+
+ return total;
+}
+
+static void genmap(int w, int h, int n, int *map, random_state *rs)
+{+ int wh = w*h;
+ int x, y, i, k;
+ int *tmp;
+
+ assert(n <= wh);
+ tmp = snewn(wh, int);
+
+ /*
+ * Clear the map, and set up `tmp' as a list of grid indices.
+ */
+ for (i = 0; i < wh; i++) {+ map[i] = -1;
+ tmp[i] = i;
+ }
+
+ /*
+ * Place the region seeds by selecting n members from `tmp'.
+ */
+ k = wh;
+ for (i = 0; i < n; i++) {+ int j = random_upto(rs, k);
+ map[tmp[j]] = i;
+ tmp[j] = tmp[--k];
+ }
+
+ /*
+ * Re-initialise `tmp' as a cumulative frequency table. This
+ * will store the number of possible region colours we can
+ * extend into each square.
+ */
+ cf_init(tmp, wh);
+
+ /*
+ * Go through the grid and set up the initial cumulative
+ * frequencies.
+ */
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++)
+ cf_add(tmp, wh, y*w+x,
+ extend_options(w, h, n, map, x, y, -1));
+
+ /*
+ * Now repeatedly choose a square we can extend a region into,
+ * and do so.
+ */
+ while (tmp[0] > 0) {+ int k = random_upto(rs, tmp[0]);
+ int sq;
+ int colour;
+ int xx, yy;
+
+ sq = cf_whichsym(tmp, wh, k);
+ k -= cf_clookup(tmp, wh, sq);
+ x = sq % w;
+ y = sq / w;
+ colour = extend_options(w, h, n, map, x, y, k);
+
+ map[sq] = colour;
+
+ /*
+ * Re-scan the nine cells around the one we've just
+ * modified.
+ */
+ for (yy = max(y-1, 0); yy < min(y+2, h); yy++)
+ for (xx = max(x-1, 0); xx < min(x+2, w); xx++) {+ cf_add(tmp, wh, yy*w+xx,
+ -cf_slookup(tmp, wh, yy*w+xx) +
+ extend_options(w, h, n, map, xx, yy, -1));
+ }
+ }
+
+ /*
+ * Finally, go through and normalise the region labels into
+ * order, meaning that indistinguishable maps are actually
+ * identical.
+ */
+ for (i = 0; i < n; i++)
+ tmp[i] = -1;
+ k = 0;
+ for (i = 0; i < wh; i++) {+ assert(map[i] >= 0);
+ if (tmp[map[i]] < 0)
+ tmp[map[i]] = k++;
+ map[i] = tmp[map[i]];
+ }
+
+ sfree(tmp);
+}
+
+/* ----------------------------------------------------------------------
+ * Functions to handle graphs.
+ */
+
+/*
+ * Having got a map in a square grid, convert it into a graph
+ * representation.
+ */
+static int gengraph(int w, int h, int n, int *map, int *graph)
+{+ int i, j, x, y;
+
+ /*
+ * Start by setting the graph up as an adjacency matrix. We'll
+ * turn it into a list later.
+ */
+ for (i = 0; i < n*n; i++)
+ graph[i] = 0;
+
+ /*
+ * Iterate over the map looking for all adjacencies.
+ */
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++) {+ int v, vx, vy;
+ v = map[y*w+x];
+ if (x+1 < w && (vx = map[y*w+(x+1)]) != v)
+ graph[v*n+vx] = graph[vx*n+v] = 1;
+ if (y+1 < h && (vy = map[(y+1)*w+x]) != v)
+ graph[v*n+vy] = graph[vy*n+v] = 1;
+ }
+
+ /*
+ * Turn the matrix into a list.
+ */
+ for (i = j = 0; i < n*n; i++)
+ if (graph[i])
+ graph[j++] = i;
+
+ return j;
+}
+
+static int graph_adjacent(int *graph, int n, int ngraph, int i, int j)
+{+ int v = i*n+j;
+ int top, bot, mid;
+
+ bot = -1;
+ top = ngraph;
+ while (top - bot > 1) {+ mid = (top + bot) / 2;
+ if (graph[mid] == v)
+ return TRUE;
+ else if (graph[mid] < v)
+ bot = mid;
+ else
+ top = mid;
+ }
+ return FALSE;
+}
+
+static int graph_vertex_start(int *graph, int n, int ngraph, int i)
+{+ int v = i*n;
+ int top, bot, mid;
+
+ bot = -1;
+ top = ngraph;
+ while (top - bot > 1) {+ mid = (top + bot) / 2;
+ if (graph[mid] < v)
+ bot = mid;
+ else
+ top = mid;
+ }
+ return top;
+}
+
+/* ----------------------------------------------------------------------
+ * Generate a four-colouring of a graph.
+ *
+ * FIXME: it would be nice if we could convert this recursion into
+ * pseudo-recursion using some sort of explicit stack array, for
+ * the sake of the Palm port and its limited stack.
+ */
+
+static int fourcolour_recurse(int *graph, int n, int ngraph,
+ int *colouring, int *scratch, random_state *rs)
+{+ int nfree, nvert, start, i, j, k, c, ci;
+ int cs[FOUR];
+
+ /*
+ * Find the smallest number of free colours in any uncoloured
+ * vertex, and count the number of such vertices.
+ */
+
+ nfree = FIVE; /* start off bigger than FOUR! */
+ nvert = 0;
+ for (i = 0; i < n; i++)
+ if (colouring[i] < 0 && scratch[i*FIVE+FOUR] <= nfree) {+ if (nfree > scratch[i*FIVE+FOUR]) {+ nfree = scratch[i*FIVE+FOUR];
+ nvert = 0;
+ }
+ nvert++;
+ }
+
+ /*
+ * If there aren't any uncoloured vertices at all, we're done.
+ */
+ if (nvert == 0)
+ return TRUE; /* we've got a colouring! */
+
+ /*
+ * Pick a random vertex in that set.
+ */
+ j = random_upto(rs, nvert);
+ for (i = 0; i < n; i++)
+ if (colouring[i] < 0 && scratch[i*FIVE+FOUR] == nfree)
+ if (j-- == 0)
+ break;
+ assert(i < n);
+ start = graph_vertex_start(graph, n, ngraph, i);
+
+ /*
+ * Loop over the possible colours for i, and recurse for each
+ * one.
+ */
+ ci = 0;
+ for (c = 0; c < FOUR; c++)
+ if (scratch[i*FIVE+c] == 0)
+ cs[ci++] = c;
+ shuffle(cs, ci, sizeof(*cs), rs);
+
+ while (ci-- > 0) {+ c = cs[ci];
+
+ /*
+ * Fill in this colour.
+ */
+ colouring[i] = c;
+
+ /*
+ * Update the scratch space to reflect a new neighbour
+ * of this colour for each neighbour of vertex i.
+ */
+ for (j = start; j < ngraph && graph[j] < n*(i+1); j++) {+ k = graph[j] - i*n;
+ if (scratch[k*FIVE+c] == 0)
+ scratch[k*FIVE+FOUR]--;
+ scratch[k*FIVE+c]++;
+ }
+
+ /*
+ * Recurse.
+ */
+ if (fourcolour_recurse(graph, n, ngraph, colouring, scratch, rs))
+ return TRUE; /* got one! */
+
+ /*
+ * If that didn't work, clean up and try again with a
+ * different colour.
+ */
+ for (j = start; j < ngraph && graph[j] < n*(i+1); j++) {+ k = graph[j] - i*n;
+ scratch[k*FIVE+c]--;
+ if (scratch[k*FIVE+c] == 0)
+ scratch[k*FIVE+FOUR]++;
+ }
+ colouring[i] = -1;
+ }
+
+ /*
+ * If we reach here, we were unable to find a colouring at all.
+ * (This doesn't necessarily mean the Four Colour Theorem is
+ * violated; it might just mean we've gone down a dead end and
+ * need to back up and look somewhere else. It's only an FCT
+ * violation if we get all the way back up to the top level and
+ * still fail.)
+ */
+ return FALSE;
+}
+
+static void fourcolour(int *graph, int n, int ngraph, int *colouring,
+ random_state *rs)
+{+ int *scratch;
+ int i;
+
+ /*
+ * For each vertex and each colour, we store the number of
+ * neighbours that have that colour. Also, we store the number
+ * of free colours for the vertex.
+ */
+ scratch = snewn(n * FIVE, int);
+ for (i = 0; i < n * FIVE; i++)
+ scratch[i] = (i % FIVE == FOUR ? FOUR : 0);
+
+ /*
+ * Clear the colouring to start with.
+ */
+ for (i = 0; i < n; i++)
+ colouring[i] = -1;
+
+ i = fourcolour_recurse(graph, n, ngraph, colouring, scratch, rs);
+ assert(i); /* by the Four Colour Theorem :-) */
+
+ sfree(scratch);
+}
+
+/* ----------------------------------------------------------------------
+ * Non-recursive solver.
+ */
+
+struct solver_scratch {+ unsigned char *possible; /* bitmap of colours for each region */
+ int *graph;
+ int n;
+ int ngraph;
+};
+
+static struct solver_scratch *new_scratch(int *graph, int n, int ngraph)
+{+ struct solver_scratch *sc;
+
+ sc = snew(struct solver_scratch);
+ sc->graph = graph;
+ sc->n = n;
+ sc->ngraph = ngraph;
+ sc->possible = snewn(n, unsigned char);
+
+ return sc;
+}
+
+static void free_scratch(struct solver_scratch *sc)
+{+ sfree(sc->possible);
+ sfree(sc);
+}
+
+static int place_colour(struct solver_scratch *sc,
+ int *colouring, int index, int colour)
+{+ int *graph = sc->graph, n = sc->n, ngraph = sc->ngraph;
+ int j, k;
+
+ if (!(sc->possible[index] & (1 << colour)))
+ return FALSE; /* can't do it */
+
+ sc->possible[index] = 1 << colour;
+ colouring[index] = colour;
+
+ /*
+ * Rule out this colour from all the region's neighbours.
+ */
+ for (j = graph_vertex_start(graph, n, ngraph, index);
+ j < ngraph && graph[j] < n*(index+1); j++) {+ k = graph[j] - index*n;
+ sc->possible[k] &= ~(1 << colour);
+ }
+
+ return TRUE;
+}
+
+/*
+ * Returns 0 for impossible, 1 for success, 2 for failure to
+ * converge (i.e. puzzle is either ambiguous or just too
+ * difficult).
+ */
+static int map_solver(struct solver_scratch *sc,
+ int *graph, int n, int ngraph, int *colouring,
+ int difficulty)
+{+ int i;
+
+ /*
+ * Initialise scratch space.
+ */
+ for (i = 0; i < n; i++)
+ sc->possible[i] = (1 << FOUR) - 1;
+
+ /*
+ * Place clues.
+ */
+ for (i = 0; i < n; i++)
+ if (colouring[i] >= 0) {+ if (!place_colour(sc, colouring, i, colouring[i]))
+ return 0; /* the clues aren't even consistent! */
+ }
+
+ /*
+ * Now repeatedly loop until we find nothing further to do.
+ */
+ while (1) {+ int done_something = FALSE;
+
+ if (difficulty < DIFF_EASY)
+ break; /* can't do anything at all! */
+
+ /*
+ * Simplest possible deduction: find a region with only one
+ * possible colour.
+ */
+ for (i = 0; i < n; i++) if (colouring[i] < 0) {+ int p = sc->possible[i];
+
+ if (p == 0)
+ return 0; /* puzzle is inconsistent */
+
+ if ((p & (p-1)) == 0) { /* p is a power of two */+ int c;
+ for (c = 0; c < FOUR; c++)
+ if (p == (1 << c))
+ break;
+ assert(c < FOUR);
+ if (!place_colour(sc, colouring, i, c))
+ return 0; /* found puzzle to be inconsistent */
+ done_something = TRUE;
+ }
+ }
+
+ if (done_something)
+ continue;
+
+ if (difficulty < DIFF_NORMAL)
+ break; /* can't do anything harder */
+
+ /*
+ * Failing that, go up one level. Look for pairs of regions
+ * which (a) both have the same pair of possible colours,
+ * (b) are adjacent to one another, (c) are adjacent to the
+ * same region, and (d) that region still thinks it has one
+ * or both of those possible colours.
+ *
+ * Simplest way to do this is by going through the graph
+ * edge by edge, so that we start with property (b) and
+ * then look for (a) and finally (c) and (d).
+ */
+ for (i = 0; i < ngraph; i++) {+ int j1 = graph[i] / n, j2 = graph[i] % n;
+ int j, k, v, v2;
+
+ if (j1 > j2)
+ continue; /* done it already, other way round */
+
+ if (colouring[j1] >= 0 || colouring[j2] >= 0)
+ continue; /* they're not undecided */
+
+ if (sc->possible[j1] != sc->possible[j2])
+ continue; /* they don't have the same possibles */
+
+ v = sc->possible[j1];
+ /*
+ * See if v contains exactly two set bits.
+ */
+ v2 = v & -v; /* find lowest set bit */
+ v2 = v & ~v2; /* clear it */
+ if (v2 == 0 || (v2 & (v2-1)) != 0) /* not power of 2 */
+ continue;
+
+ /*
+ * We've found regions j1 and j2 satisfying properties
+ * (a) and (b): they have two possible colours between
+ * them, and since they're adjacent to one another they
+ * must use _both_ those colours between them.
+ * Therefore, if they are both adjacent to any other
+ * region then that region cannot be either colour.
+ *
+ * Go through the neighbours of j1 and see if any are
+ * shared with j2.
+ */
+ for (j = graph_vertex_start(graph, n, ngraph, j1);
+ j < ngraph && graph[j] < n*(j1+1); j++) {+ k = graph[j] - j1*n;
+ if (graph_adjacent(graph, n, ngraph, k, j2) &&
+ (sc->possible[k] & v)) {+ sc->possible[k] &= ~v;
+ done_something = TRUE;
+ }
+ }
+ }
+
+ if (!done_something)
+ break;
+ }
+
+ /*
+ * We've run out of things to deduce. See if we've got the lot.
+ */
+ for (i = 0; i < n; i++)
+ if (colouring[i] < 0)
+ return 2;
+
+ return 1; /* success! */
+}
+
+/* ----------------------------------------------------------------------
+ * Game generation main function.
+ */
+
+static char *new_game_desc(game_params *params, random_state *rs,
+ char **aux, int interactive)
+{+ struct solver_scratch *sc;
+ int *map, *graph, ngraph, *colouring, *colouring2, *regions;
+ int i, j, w, h, n, solveret, cfreq[FOUR];
+ int wh;
+ int mindiff, tries;
+#ifdef GENERATION_DIAGNOSTICS
+ int x, y;
+#endif
+ char *ret, buf[80];
+ int retlen, retsize;
+
+ w = params->w;
+ h = params->h;
+ n = params->n;
+ wh = w*h;
+
+ *aux = NULL;
+
+ map = snewn(wh, int);
+ graph = snewn(n*n, int);
+ colouring = snewn(n, int);
+ colouring2 = snewn(n, int);
+ regions = snewn(n, int);
+
+ /*
+ * This is the minimum difficulty below which we'll completely
+ * reject a map design. Normally we set this to one below the
+ * requested difficulty, ensuring that we have the right
+ * result. However, for particularly dense maps or maps with
+ * particularly few regions it might not be possible to get the
+ * desired difficulty, so we will eventually drop this down to
+ * -1 to indicate that any old map will do.
+ */
+ mindiff = params->diff;
+ tries = 50;
+
+ while (1) {+
+ /*
+ * Create the map.
+ */
+ genmap(w, h, n, map, rs);
+
+#ifdef GENERATION_DIAGNOSTICS
+ for (y = 0; y < h; y++) {+ for (x = 0; x < w; x++) {+ int v = map[y*w+x];
+ if (v >= 62)
+ putchar('!');+ else if (v >= 36)
+ putchar('a' + v-36);+ else if (v >= 10)
+ putchar('A' + v-10);+ else
+ putchar('0' + v);+ }
+ putchar('\n');+ }
+#endif
+
+ /*
+ * Convert the map into a graph.
+ */
+ ngraph = gengraph(w, h, n, map, graph);
+
+#ifdef GENERATION_DIAGNOSTICS
+ for (i = 0; i < ngraph; i++)
+ printf("%d-%d\n", graph[i]/n, graph[i]%n);+#endif
+
+ /*
+ * Colour the map.
+ */
+ fourcolour(graph, n, ngraph, colouring, rs);
+
+#ifdef GENERATION_DIAGNOSTICS
+ for (i = 0; i < n; i++)
+ printf("%d: %d\n", i, colouring[i]);+
+ for (y = 0; y < h; y++) {+ for (x = 0; x < w; x++) {+ int v = colouring[map[y*w+x]];
+ if (v >= 36)
+ putchar('a' + v-36);+ else if (v >= 10)
+ putchar('A' + v-10);+ else
+ putchar('0' + v);+ }
+ putchar('\n');+ }
+#endif
+
+ /*
+ * Encode the solution as an aux string.
+ */
+ if (*aux) /* in case we've come round again */
+ sfree(*aux);
+ retlen = retsize = 0;
+ ret = NULL;
+ for (i = 0; i < n; i++) {+ int len;
+
+ if (colouring[i] < 0)
+ continue;
+
+ len = sprintf(buf, "%s%d:%d", i ? ";" : "S;", colouring[i], i);
+ if (retlen + len >= retsize) {+ retsize = retlen + len + 256;
+ ret = sresize(ret, retsize, char);
+ }
+ strcpy(ret + retlen, buf);
+ retlen += len;
+ }
+ *aux = ret;
+
+ /*
+ * Remove the region colours one by one, keeping
+ * solubility. Also ensure that there always remains at
+ * least one region of every colour, so that the user can
+ * drag from somewhere.
+ */
+ for (i = 0; i < FOUR; i++)
+ cfreq[i] = 0;
+ for (i = 0; i < n; i++) {+ regions[i] = i;
+ cfreq[colouring[i]]++;
+ }
+ for (i = 0; i < FOUR; i++)
+ if (cfreq[i] == 0)
+ continue;
+
+ shuffle(regions, n, sizeof(*regions), rs);
+
+ sc = new_scratch(graph, n, ngraph);
+
+ for (i = 0; i < n; i++) {+ j = regions[i];
+
+ if (cfreq[colouring[j]] == 1)
+ continue; /* can't remove last region of colour */
+
+ memcpy(colouring2, colouring, n*sizeof(int));
+ colouring2[j] = -1;
+ solveret = map_solver(sc, graph, n, ngraph, colouring2,
+ params->diff);
+ assert(solveret >= 0); /* mustn't be impossible! */
+ if (solveret == 1) {+ cfreq[colouring[j]]--;
+ colouring[j] = -1;
+ }
+ }
+
+#ifdef GENERATION_DIAGNOSTICS
+ for (i = 0; i < n; i++)
+ if (colouring[i] >= 0) {+ if (i >= 62)
+ putchar('!');+ else if (i >= 36)
+ putchar('a' + i-36);+ else if (i >= 10)
+ putchar('A' + i-10);+ else
+ putchar('0' + i);+ printf(": %d\n", colouring[i]);+ }
+#endif
+
+ /*
+ * Finally, check that the puzzle is _at least_ as hard as
+ * required, and indeed that it isn't already solved.
+ * (Calling map_solver with negative difficulty ensures the
+ * latter - if a solver which _does nothing_ can't solve
+ * it, it's too easy!)
+ */
+ memcpy(colouring2, colouring, n*sizeof(int));
+ if (map_solver(sc, graph, n, ngraph, colouring2,
+ mindiff - 1) == 1) {+ /*
+ * Drop minimum difficulty if necessary.
+ */
+ if (mindiff > 0 && (n < 9 || n > 3*wh/2)) {+ if (tries-- <= 0)
+ mindiff = 0; /* give up and go for Easy */
+ }
+ continue;
+ }
+
+ break;
+ }
+
+ /*
+ * Encode as a game ID. We do this by:
+ *
+ * - first going along the horizontal edges row by row, and
+ * then the vertical edges column by column
+ * - encoding the lengths of runs of edges and runs of
+ * non-edges
+ * - the decoder will reconstitute the region boundaries from
+ * this and automatically number them the same way we did
+ * - then we encode the initial region colours in a Slant-like
+ * fashion (digits 0-3 interspersed with letters giving
+ * lengths of runs of empty spaces).
+ */
+ retlen = retsize = 0;
+ ret = NULL;
+
+ {+ int run, pv;
+
+ /*
+ * Start with a notional non-edge, so that there'll be an
+ * explicit `a' to distinguish the case where we start with
+ * an edge.
+ */
+ run = 1;
+ pv = 0;
+
+ for (i = 0; i < w*(h-1) + (w-1)*h; i++) {+ int x, y, dx, dy, v;
+
+ if (i < w*(h-1)) {+ /* Horizontal edge. */
+ y = i / w;
+ x = i % w;
+ dx = 0;
+ dy = 1;
+ } else {+ /* Vertical edge. */
+ x = (i - w*(h-1)) / h;
+ y = (i - w*(h-1)) % h;
+ dx = 1;
+ dy = 0;
+ }
+
+ if (retlen + 10 >= retsize) {+ retsize = retlen + 256;
+ ret = sresize(ret, retsize, char);
+ }
+
+ v = (map[y*w+x] != map[(y+dy)*w+(x+dx)]);
+
+ if (pv != v) {+ ret[retlen++] = 'a'-1 + run;
+ run = 1;
+ pv = v;
+ } else {+ /*
+ * 'z' is a special case in this encoding. Rather
+ * than meaning a run of 26 and a state switch, it
+ * means a run of 25 and _no_ state switch, because
+ * otherwise there'd be no way to encode runs of
+ * more than 26.
+ */
+ if (run == 25) {+ ret[retlen++] = 'z';
+ run = 0;
+ }
+ run++;
+ }
+ }
+
+ ret[retlen++] = 'a'-1 + run;
+ ret[retlen++] = ',';
+
+ run = 0;
+ for (i = 0; i < n; i++) {+ if (retlen + 10 >= retsize) {+ retsize = retlen + 256;
+ ret = sresize(ret, retsize, char);
+ }
+
+ if (colouring[i] < 0) {+ /*
+ * In _this_ encoding, 'z' is a run of 26, since
+ * there's no implicit state switch after each run.
+ * Confusingly different, but more compact.
+ */
+ if (run == 26) {+ ret[retlen++] = 'z';
+ run = 0;
+ }
+ run++;
+ } else {+ if (run > 0)
+ ret[retlen++] = 'a'-1 + run;
+ ret[retlen++] = '0' + colouring[i];
+ run = 0;
+ }
+ }
+ if (run > 0)
+ ret[retlen++] = 'a'-1 + run;
+ ret[retlen] = '\0';
+
+ assert(retlen < retsize);
+ }
+
+ free_scratch(sc);
+ sfree(regions);
+ sfree(colouring2);
+ sfree(colouring);
+ sfree(graph);
+ sfree(map);
+
+ return ret;
+}
+
+static char *parse_edge_list(game_params *params, char **desc, int *map)
+{+ int w = params->w, h = params->h, wh = w*h, n = params->n;
+ int i, k, pos, state;
+ char *p = *desc;
+
+ for (i = 0; i < wh; i++)
+ map[wh+i] = i;
+
+ pos = -1;
+ state = 0;
+
+ /*
+ * Parse the game description to get the list of edges, and
+ * build up a disjoint set forest as we go (by identifying
+ * pairs of squares whenever the edge list shows a non-edge).
+ */
+ while (*p && *p != ',') {+ if (*p < 'a' || *p > 'z')
+ return "Unexpected character in edge list";
+ if (*p == 'z')
+ k = 25;
+ else
+ k = *p - 'a' + 1;
+ while (k-- > 0) {+ int x, y, dx, dy;
+
+ if (pos < 0) {+ pos++;
+ continue;
+ } else if (pos < w*(h-1)) {+ /* Horizontal edge. */
+ y = pos / w;
+ x = pos % w;
+ dx = 0;
+ dy = 1;
+ } else if (pos < 2*wh-w-h) {+ /* Vertical edge. */
+ x = (pos - w*(h-1)) / h;
+ y = (pos - w*(h-1)) % h;
+ dx = 1;
+ dy = 0;
+ } else
+ return "Too much data in edge list";
+ if (!state)
+ dsf_merge(map+wh, y*w+x, (y+dy)*w+(x+dx));
+
+ pos++;
+ }
+ if (*p != 'z')
+ state = !state;
+ p++;
+ }
+ assert(pos <= 2*wh-w-h);
+ if (pos < 2*wh-w-h)
+ return "Too little data in edge list";
+
+ /*
+ * Now go through again and allocate region numbers.
+ */
+ pos = 0;
+ for (i = 0; i < wh; i++)
+ map[i] = -1;
+ for (i = 0; i < wh; i++) {+ k = dsf_canonify(map+wh, i);
+ if (map[k] < 0)
+ map[k] = pos++;
+ map[i] = map[k];
+ }
+ if (pos != n)
+ return "Edge list defines the wrong number of regions";
+
+ *desc = p;
+
+ return NULL;
+}
+
+static char *validate_desc(game_params *params, char *desc)
+{+ int w = params->w, h = params->h, wh = w*h, n = params->n;
+ int area;
+ int *map;
+ char *ret;
+
+ map = snewn(2*wh, int);
+ ret = parse_edge_list(params, &desc, map);
+ if (ret)
+ return ret;
+ sfree(map);
+
+ if (*desc != ',')
+ return "Expected comma before clue list";
+ desc++; /* eat comma */
+
+ area = 0;
+ while (*desc) {+ if (*desc >= '0' && *desc < '0'+FOUR)
+ area++;
+ else if (*desc >= 'a' && *desc <= 'z')
+ area += *desc - 'a' + 1;
+ else
+ return "Unexpected character in clue list";
+ desc++;
+ }
+ if (area < n)
+ return "Too little data in clue list";
+ else if (area > n)
+ return "Too much data in clue list";
+
+ return NULL;
+}
+
+static game_state *new_game(midend_data *me, game_params *params, char *desc)
+{+ int w = params->w, h = params->h, wh = w*h, n = params->n;
+ int i, pos;
+ char *p;
+ game_state *state = snew(game_state);
+
+ state->p = *params;
+ state->colouring = snewn(n, int);
+ for (i = 0; i < n; i++)
+ state->colouring[i] = -1;
+
+ state->completed = state->cheated = FALSE;
+
+ state->map = snew(struct map);
+ state->map->refcount = 1;
+ state->map->map = snewn(wh*4, int);
+ state->map->graph = snewn(n*n, int);
+ state->map->n = n;
+ state->map->immutable = snewn(n, int);
+ for (i = 0; i < n; i++)
+ state->map->immutable[i] = FALSE;
+
+ p = desc;
+
+ {+ char *ret;
+ ret = parse_edge_list(params, &p, state->map->map);
+ assert(!ret);
+ }
+
+ /*
+ * Set up the other three quadrants in `map'.
+ */
+ for (i = wh; i < 4*wh; i++)
+ state->map->map[i] = state->map->map[i % wh];
+
+ assert(*p == ',');
+ p++;
+
+ /*
+ * Now process the clue list.
+ */
+ pos = 0;
+ while (*p) {+ if (*p >= '0' && *p < '0'+FOUR) {+ state->colouring[pos] = *p - '0';
+ state->map->immutable[pos] = TRUE;
+ pos++;
+ } else {+ assert(*p >= 'a' && *p <= 'z');
+ pos += *p - 'a' + 1;
+ }
+ p++;
+ }
+ assert(pos == n);
+
+ state->map->ngraph = gengraph(w, h, n, state->map->map, state->map->graph);
+
+ /*
+ * Attempt to smooth out some of the more jagged region
+ * outlines by the judicious use of diagonally divided squares.
+ */
+ {+ random_state *rs = random_init(desc, strlen(desc));
+ int *squares = snewn(wh, int);
+ int done_something;
+
+ for (i = 0; i < wh; i++)
+ squares[i] = i;
+ shuffle(squares, wh, sizeof(*squares), rs);
+
+ do {+ done_something = FALSE;
+ for (i = 0; i < wh; i++) {+ int y = squares[i] / w, x = squares[i] % w;
+ int c = state->map->map[y*w+x];
+ int tc, bc, lc, rc;
+
+ if (x == 0 || x == w-1 || y == 0 || y == h-1)
+ continue;
+
+ if (state->map->map[TE * wh + y*w+x] !=
+ state->map->map[BE * wh + y*w+x])
+ continue;
+
+ tc = state->map->map[BE * wh + (y-1)*w+x];
+ bc = state->map->map[TE * wh + (y+1)*w+x];
+ lc = state->map->map[RE * wh + y*w+(x-1)];
+ rc = state->map->map[LE * wh + y*w+(x+1)];
+
+ /*
+ * If this square is adjacent on two sides to one
+ * region and on the other two sides to the other
+ * region, and is itself one of the two regions, we can
+ * adjust it so that it's a diagonal.
+ */
+ if (tc != bc && (tc == c || bc == c)) {+ if ((lc == tc && rc == bc) ||
+ (lc == bc && rc == tc)) {+ state->map->map[TE * wh + y*w+x] = tc;
+ state->map->map[BE * wh + y*w+x] = bc;
+ state->map->map[LE * wh + y*w+x] = lc;
+ state->map->map[RE * wh + y*w+x] = rc;
+ done_something = TRUE;
+ }
+ }
+ }
+ } while (done_something);
+ sfree(squares);
+ random_free(rs);
+ }
+
+ return state;
+}
+
+static game_state *dup_game(game_state *state)
+{+ game_state *ret = snew(game_state);
+
+ ret->p = state->p;
+ ret->colouring = snewn(state->p.n, int);
+ memcpy(ret->colouring, state->colouring, state->p.n * sizeof(int));
+ ret->map = state->map;
+ ret->map->refcount++;
+ ret->completed = state->completed;
+ ret->cheated = state->cheated;
+
+ return ret;
+}
+
+static void free_game(game_state *state)
+{+ if (--state->map->refcount <= 0) {+ sfree(state->map->map);
+ sfree(state->map->graph);
+ sfree(state->map->immutable);
+ sfree(state->map);
+ }
+ sfree(state->colouring);
+ sfree(state);
+}
+
+static char *solve_game(game_state *state, game_state *currstate,
+ char *aux, char **error)
+{+ if (!aux) {+ /*
+ * Use the solver.
+ */
+ int *colouring;
+ struct solver_scratch *sc;
+ int sret;
+ int i;
+ char *ret, buf[80];
+ int retlen, retsize;
+
+ colouring = snewn(state->map->n, int);
+ memcpy(colouring, state->colouring, state->map->n * sizeof(int));
+
+ sc = new_scratch(state->map->graph, state->map->n, state->map->ngraph);
+ sret = map_solver(sc, state->map->graph, state->map->n,
+ state->map->ngraph, colouring, DIFFCOUNT-1);
+ free_scratch(sc);
+
+ if (sret != 1) {+ sfree(colouring);
+ if (sret == 0)
+ *error = "Puzzle is inconsistent";
+ else
+ *error = "Unable to find a unique solution for this puzzle";
+ return NULL;
+ }
+
+ retlen = retsize = 0;
+ ret = NULL;
+
+ for (i = 0; i < state->map->n; i++) {+ int len;
+
+ assert(colouring[i] >= 0);
+ if (colouring[i] == currstate->colouring[i])
+ continue;
+ assert(!state->map->immutable[i]);
+
+ len = sprintf(buf, "%s%d:%d", retlen ? ";" : "S;",
+ colouring[i], i);
+ if (retlen + len >= retsize) {+ retsize = retlen + len + 256;
+ ret = sresize(ret, retsize, char);
+ }
+ strcpy(ret + retlen, buf);
+ retlen += len;
+ }
+
+ sfree(colouring);
+
+ return ret;
+ }
+ return dupstr(aux);
+}
+
+static char *game_text_format(game_state *state)
+{+ return NULL;
+}
+
+struct game_ui {+ int drag_colour; /* -1 means no drag active */
+ int dragx, dragy;
+};
+
+static game_ui *new_ui(game_state *state)
+{+ game_ui *ui = snew(game_ui);
+ ui->dragx = ui->dragy = -1;
+ ui->drag_colour = -2;
+ return ui;
+}
+
+static void free_ui(game_ui *ui)
+{+ sfree(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)
+{+}
+
+struct game_drawstate {+ int tilesize;
+ unsigned char *drawn;
+ int started;
+ int dragx, dragy, drag_visible;
+ blitter *bl;
+};
+
+#define TILESIZE (ds->tilesize)
+#define BORDER (TILESIZE)
+#define COORD(x) ( (x) * TILESIZE + BORDER )
+#define FROMCOORD(x) ( ((x) - BORDER + TILESIZE) / TILESIZE - 1 )
+
+static int region_from_coords(game_state *state, game_drawstate *ds,
+ int x, int y)
+{+ int w = state->p.w, h = state->p.h, wh = w*h /*, n = state->p.n */;
+ int tx = FROMCOORD(x), ty = FROMCOORD(y);
+ int dx = x - COORD(tx), dy = y - COORD(ty);
+ int quadrant;
+
+ if (tx < 0 || tx >= w || ty < 0 || ty >= h)
+ return -1; /* border */
+
+ quadrant = 2 * (dx > dy) + (TILESIZE - dx > dy);
+ quadrant = (quadrant == 0 ? BE :
+ quadrant == 1 ? LE :
+ quadrant == 2 ? RE : TE);
+
+ return state->map->map[quadrant * wh + ty*w+tx];
+}
+
+static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
+ int x, int y, int button)
+{+ char buf[80];
+
+ if (button == LEFT_BUTTON || button == RIGHT_BUTTON) {+ int r = region_from_coords(state, ds, x, y);
+
+ if (r >= 0)
+ ui->drag_colour = state->colouring[r];
+ else
+ ui->drag_colour = -1;
+ ui->dragx = x;
+ ui->dragy = y;
+ return "";
+ }
+
+ if ((button == LEFT_DRAG || button == RIGHT_DRAG) &&
+ ui->drag_colour > -2) {+ ui->dragx = x;
+ ui->dragy = y;
+ return "";
+ }
+
+ if ((button == LEFT_RELEASE || button == RIGHT_RELEASE) &&
+ ui->drag_colour > -2) {+ int r = region_from_coords(state, ds, x, y);
+ int c = ui->drag_colour;
+
+ /*
+ * Cancel the drag, whatever happens.
+ */
+ ui->drag_colour = -2;
+ ui->dragx = ui->dragy = -1;
+
+ if (r < 0)
+ return ""; /* drag into border; do nothing else */
+
+ if (state->map->immutable[r])
+ return ""; /* can't change this region */
+
+ if (state->colouring[r] == c)
+ return ""; /* don't _need_ to change this region */
+
+ sprintf(buf, "%c:%d", (c < 0 ? 'C' : '0' + c), r);
+ return dupstr(buf);
+ }
+
+ return NULL;
+}
+
+static game_state *execute_move(game_state *state, char *move)
+{+ int n = state->p.n;
+ game_state *ret = dup_game(state);
+ int c, k, adv, i;
+
+ while (*move) {+ c = *move;
+ if ((c == 'C' || (c >= '0' && c < '0'+FOUR)) &&
+ sscanf(move+1, ":%d%n", &k, &adv) == 1 &&
+ k >= 0 && k < state->p.n) {+ move += 1 + adv;
+ ret->colouring[k] = (c == 'C' ? -1 : c - '0');
+ } else if (*move == 'S') {+ move++;
+ ret->cheated = TRUE;
+ } else {+ free_game(ret);
+ return NULL;
+ }
+
+ if (*move && *move != ';') {+ free_game(ret);
+ return NULL;
+ }
+ if (*move)
+ move++;
+ }
+
+ /*
+ * Check for completion.
+ */
+ if (!ret->completed) {+ int ok = TRUE;
+
+ for (i = 0; i < n; i++)
+ if (ret->colouring[i] < 0) {+ ok = FALSE;
+ break;
+ }
+
+ if (ok) {+ for (i = 0; i < ret->map->ngraph; i++) {+ int j = ret->map->graph[i] / n;
+ int k = ret->map->graph[i] % n;
+ if (ret->colouring[j] == ret->colouring[k]) {+ ok = FALSE;
+ break;
+ }
+ }
+ }
+
+ if (ok)
+ ret->completed = TRUE;
+ }
+
+ return ret;
+}
+
+/* ----------------------------------------------------------------------
+ * Drawing routines.
+ */
+
+static void game_compute_size(game_params *params, int tilesize,
+ int *x, int *y)
+{+ /* Ick: fake up `ds->tilesize' for macro expansion purposes */
+ struct { int tilesize; } ads, *ds = &ads;+ ads.tilesize = tilesize;
+
+ *x = params->w * TILESIZE + 2 * BORDER + 1;
+ *y = params->h * TILESIZE + 2 * BORDER + 1;
+}
+
+static void game_set_size(game_drawstate *ds, game_params *params,
+ int tilesize)
+{+ ds->tilesize = tilesize;
+
+ if (ds->bl)
+ blitter_free(ds->bl);
+ ds->bl = blitter_new(TILESIZE+3, TILESIZE+3);
+}
+
+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_0 * 3 + 0] = 0.7F;
+ ret[COL_0 * 3 + 1] = 0.5F;
+ ret[COL_0 * 3 + 2] = 0.4F;
+
+ ret[COL_1 * 3 + 0] = 0.8F;
+ ret[COL_1 * 3 + 1] = 0.7F;
+ ret[COL_1 * 3 + 2] = 0.4F;
+
+ ret[COL_2 * 3 + 0] = 0.5F;
+ ret[COL_2 * 3 + 1] = 0.6F;
+ ret[COL_2 * 3 + 2] = 0.4F;
+
+ ret[COL_3 * 3 + 0] = 0.55F;
+ ret[COL_3 * 3 + 1] = 0.45F;
+ ret[COL_3 * 3 + 2] = 0.35F;
+
+ *ncolours = NCOLOURS;
+ return ret;
+}
+
+static game_drawstate *game_new_drawstate(game_state *state)
+{+ struct game_drawstate *ds = snew(struct game_drawstate);
+
+ ds->tilesize = 0;
+ ds->drawn = snewn(state->p.w * state->p.h, unsigned char);
+ memset(ds->drawn, 0xFF, state->p.w * state->p.h);
+ ds->started = FALSE;
+ ds->bl = NULL;
+ ds->drag_visible = FALSE;
+ ds->dragx = ds->dragy = -1;
+
+ return ds;
+}
+
+static void game_free_drawstate(game_drawstate *ds)
+{+ if (ds->bl)
+ blitter_free(ds->bl);
+ sfree(ds);
+}
+
+static void draw_square(frontend *fe, game_drawstate *ds,
+ game_params *params, struct map *map,
+ int x, int y, int v)
+{+ int w = params->w, h = params->h, wh = w*h;
+ int tv = v / FIVE, bv = v % FIVE;
+
+ clip(fe, COORD(x), COORD(y), TILESIZE, TILESIZE);
+
+ /*
+ * Draw the region colour.
+ */
+ draw_rect(fe, COORD(x), COORD(y), TILESIZE, TILESIZE,
+ (tv == FOUR ? COL_BACKGROUND : COL_0 + tv));
+ /*
+ * Draw the second region colour, if this is a diagonally
+ * divided square.
+ */
+ if (map->map[TE * wh + y*w+x] != map->map[BE * wh + y*w+x]) {+ int coords[6];
+ coords[0] = COORD(x)-1;
+ coords[1] = COORD(y+1)+1;
+ if (map->map[LE * wh + y*w+x] == map->map[TE * wh + y*w+x])
+ coords[2] = COORD(x+1)+1;
+ else
+ coords[2] = COORD(x)-1;
+ coords[3] = COORD(y)-1;
+ coords[4] = COORD(x+1)+1;
+ coords[5] = COORD(y+1)+1;
+ draw_polygon(fe, coords, 3,
+ (bv == FOUR ? COL_BACKGROUND : COL_0 + bv), COL_GRID);
+ }
+
+ /*
+ * Draw the grid lines, if required.
+ */
+ if (x <= 0 || map->map[RE*wh+y*w+(x-1)] != map->map[LE*wh+y*w+x])
+ draw_rect(fe, COORD(x), COORD(y), 1, TILESIZE, COL_GRID);
+ if (y <= 0 || map->map[BE*wh+(y-1)*w+x] != map->map[TE*wh+y*w+x])
+ draw_rect(fe, COORD(x), COORD(y), TILESIZE, 1, COL_GRID);
+ if (x <= 0 || y <= 0 ||
+ map->map[RE*wh+(y-1)*w+(x-1)] != map->map[TE*wh+y*w+x] ||
+ map->map[BE*wh+(y-1)*w+(x-1)] != map->map[LE*wh+y*w+x])
+ draw_rect(fe, COORD(x), COORD(y), 1, 1, COL_GRID);
+
+ unclip(fe);
+ draw_update(fe, COORD(x), COORD(y), TILESIZE, TILESIZE);
+}
+
+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 w = state->p.w, h = state->p.h, wh = w*h /*, n = state->p.n */;
+ int x, y;
+ int flash;
+
+ if (ds->drag_visible) {+ blitter_load(fe, ds->bl, ds->dragx, ds->dragy);
+ draw_update(fe, ds->dragx, ds->dragy, TILESIZE + 3, TILESIZE + 3);
+ ds->drag_visible = FALSE;
+ }
+
+ /*
+ * 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.
+ */
+ if (!ds->started) {+ int ww, wh;
+
+ game_compute_size(&state->p, TILESIZE, &ww, &wh);
+ draw_rect(fe, 0, 0, ww, wh, COL_BACKGROUND);
+ draw_rect(fe, COORD(0), COORD(0), w*TILESIZE+1, h*TILESIZE+1,
+ COL_GRID);
+
+ draw_update(fe, 0, 0, ww, wh);
+ ds->started = TRUE;
+ }
+
+ if (flashtime) {+ if (flash_type == 1)
+ flash = (int)(flashtime * FOUR / flash_length);
+ else
+ flash = 1 + (int)(flashtime * THREE / flash_length);
+ } else
+ flash = -1;
+
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++) {+ int tv = state->colouring[state->map->map[TE * wh + y*w+x]];
+ int bv = state->colouring[state->map->map[BE * wh + y*w+x]];
+ int v;
+
+ if (tv < 0)
+ tv = FOUR;
+ if (bv < 0)
+ bv = FOUR;
+
+ if (flash >= 0) {+ if (flash_type == 1) {+ if (tv == flash)
+ tv = FOUR;
+ if (bv == flash)
+ bv = FOUR;
+ } else if (flash_type == 2) {+ if (flash % 2)
+ tv = bv = FOUR;
+ } else {+ if (tv != FOUR)
+ tv = (tv + flash) % FOUR;
+ if (bv != FOUR)
+ bv = (bv + flash) % FOUR;
+ }
+ }
+
+ v = tv * FIVE + bv;
+
+ if (ds->drawn[y*w+x] != v) {+ draw_square(fe, ds, &state->p, state->map, x, y, v);
+ ds->drawn[y*w+x] = v;
+ }
+ }
+
+ /*
+ * Draw the dragged colour blob if any.
+ */
+ if (ui->drag_colour > -2) {+ ds->dragx = ui->dragx - TILESIZE/2 - 2;
+ ds->dragy = ui->dragy - TILESIZE/2 - 2;
+ blitter_save(fe, ds->bl, ds->dragx, ds->dragy);
+ draw_circle(fe, ui->dragx, ui->dragy, TILESIZE/2,
+ (ui->drag_colour < 0 ? COL_BACKGROUND :
+ COL_0 + ui->drag_colour), COL_GRID);
+ draw_update(fe, ds->dragx, ds->dragy, TILESIZE + 3, TILESIZE + 3);
+ ds->drag_visible = TRUE;
+ }
+}
+
+static float game_anim_length(game_state *oldstate, 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)
+{+ if (!oldstate->completed && newstate->completed &&
+ !oldstate->cheated && !newstate->cheated) {+ if (flash_type < 0) {+ char *env = getenv("MAP_ALTERNATIVE_FLASH");+ if (env)
+ flash_type = atoi(env);
+ else
+ flash_type = 0;
+ flash_length = (flash_type == 1 ? 0.50 : 0.30);
+ }
+ return flash_length;
+ } else
+ return 0.0F;
+}
+
+static int game_wants_statusbar(void)
+{+ return FALSE;
+}
+
+static int game_timing_state(game_state *state, game_ui *ui)
+{+ return TRUE;
+}
+
+#ifdef COMBINED
+#define thegame map
+#endif
+
+const struct game thegame = {+ "Map", "games.map",
+ 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,
+ TRUE, solve_game,
+ FALSE, game_text_format,
+ new_ui,
+ free_ui,
+ encode_ui,
+ decode_ui,
+ game_changed_state,
+ interpret_move,
+ execute_move,
+ 20, game_compute_size, game_set_size,
+ game_colours,
+ game_new_drawstate,
+ game_free_drawstate,
+ game_redraw,
+ game_anim_length,
+ game_flash_length,
+ game_wants_statusbar,
+ FALSE, game_timing_state,
+ 0, /* mouse_priorities */
+};
--- a/puzzles.but
+++ b/puzzles.but
@@ -1582,6 +1582,66 @@
probably be necessary.
+\C{map} \i{Map}+
+\cfg{winhelp-topic}{games.map}+
+You are given a map consisting of a number of regions. Your task is
+to colour each region with one of four colours, in such a way that
+no two regions sharing a boundary have the same colour. You are
+provided with some regions already coloured, sufficient to make the
+remainder of the solution unique.
+
+Only regions which share a length of border are required to be
+different colours. Two regions which meet at only one \e{point}+(i.e. are diagonally separated) may be the same colour.
+
+I believe this puzzle is original; I've never seen an implementation
+of it anywhere else. The concept of a four-colouring puzzle was
+suggested by Owen Dunn; credit must also go to Nikoli and to Verity
+Allan for inspiring the train of thought that led to me realising
+Owen's suggestion was a viable puzzle. Thanks also to Gareth Taylor
+for many detailed suggestions.
+
+
+\H{map-controls} \i{Map controls}+
+\IM{Map controls} controls, for Map+\IM{Map controls} keys, for Map+\IM{Map controls} shortcuts (keyboard), for Map+
+To colour a region, click on an existing region of the desired
+colour and drag that colour into the new region.
+
+(The program will always ensure the starting puzzle has at least one
+region of each colour, so that this is always possible!)
+
+If you need to clear a region, you can drag from an empty region, or
+from the puzzle boundary if there are no empty regions left.
+
+
+\H{map-parameters} \I{parameters, for Map}Map parameters+
+These parameters are available from the \q{Custom...} option on the+\q{Type} menu.+
+\dt \e{Width}, \e{Height}+
+\dd Size of grid in squares.
+
+\dt \e{Regions}+
+\dd Number of regions in the generated map.
+
+\dt \e{Difficulty}+
+\dd In \q{Easy} mode, there should always be at least one region+whose colour can be determined trivially. In \q{Normal} mode, you+will have to use more complex logic to deduce the colour of some
+regions. However, it will always be possible without having to
+guess or backtrack.
+
+
\A{licence} \I{MIT licence}\ii{Licence} This software is \i{copyright} 2004-2005 Simon Tatham.