1 /****************************************************************************
2 * Copyright 2018-2021,2022 Thomas E. Dickey *
3 * Copyright 1998-2013,2017 Free Software Foundation, Inc. *
5 * Permission is hereby granted, free of charge, to any person obtaining a *
6 * copy of this software and associated documentation files (the *
7 * "Software"), to deal in the Software without restriction, including *
8 * without limitation the rights to use, copy, modify, merge, publish, *
9 * distribute, distribute with modifications, sublicense, and/or sell *
10 * copies of the Software, and to permit persons to whom the Software is *
11 * furnished to do so, subject to the following conditions: *
13 * The above copyright notice and this permission notice shall be included *
14 * in all copies or substantial portions of the Software. *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
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21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
24 * Except as contained in this notice, the name(s) of the above copyright *
25 * holders shall not be used in advertising or otherwise to promote the *
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28 ****************************************************************************/
30 * Knight's Tour - a brain game
32 * The original of this game was anonymous. It had an unbelievably bogus
33 * interface, you actually had to enter square coordinates! Redesign by
34 * Eric S. Raymond <esr@snark.thyrsus.com> July 22 1995. Mouse support
35 * added September 20th 1995.
37 * $Id: knight.c,v 1.52 2022/12/04 00:40:11 tom Exp $
40 #include <test.priv.h>
45 #define MAXMOVES (ylimit * xlimit)
47 /* where to start the instructions */
55 /* notification line */
58 /* virtual color values */
63 #define CX(x) (2 + 4 * (x))
64 #define CY(y) (1 + 2 * (y))
65 #define cellmove(y, x) wmove(boardwin, CY(y), CX(x))
66 #define CXINV(x) (((x) - 1) / 4)
67 #define CYINV(y) (((y) - 2) / 2)
73 typedef int SQUARES[YLIMIT][XLIMIT];
75 static WINDOW *boardwin; /* the board window */
76 static WINDOW *helpwin; /* the help window */
77 static WINDOW *msgwin; /* the message window */
79 #if HAVE_USE_DEFAULT_COLORS
83 static chtype minus = '-'; /* possible-move character */
85 static chtype plus = '+'; /* cursor hot-spot character */
86 static chtype trail = '#'; /* trail character */
88 static int ylimit = YLIMIT;
89 static int xlimit = XLIMIT;
90 static int maxmoves = (YLIMIT * XLIMIT);
92 static int count_tries; /* count of trials so far */
93 static int test_test; /* FIXME */
108 #define MAX_OFFSET (unsigned)SIZEOF(offsets)
114 setlocale(LC_ALL, "");
116 srand((unsigned) getpid());
118 cbreak(); /* immediate char return */
119 noecho(); /* no immediate echo */
122 boardwin = newwin(ylimit * 2 + 1, xlimit * 4 + 1, BOARDY, BOARDX);
123 helpwin = newwin(0, 0, INSTRY, INSTRX);
124 msgwin = newwin(1, INSTRX - 1, NOTIFYY, 0);
126 scrollok(msgwin, TRUE);
127 keypad(boardwin, TRUE);
130 int bg = COLOR_BLACK;
133 #if HAVE_USE_DEFAULT_COLORS
134 if (d_option && (use_default_colors() == OK))
138 (void) init_pair(TRAIL_COLOR, (short) COLOR_CYAN, (short) bg);
139 (void) init_pair(PLUS_COLOR, (short) COLOR_RED, (short) bg);
140 (void) init_pair(MINUS_COLOR, (short) COLOR_GREEN, (short) bg);
142 trail |= (chtype) COLOR_PAIR(TRAIL_COLOR);
143 plus |= (chtype) COLOR_PAIR(PLUS_COLOR);
144 minus |= (chtype) COLOR_PAIR(MINUS_COLOR);
146 #ifdef NCURSES_MOUSE_VERSION
147 (void) mousemask(BUTTON1_CLICKED, (mmask_t *) NULL);
148 #endif /* NCURSES_MOUSE_VERSION */
149 #if defined(PDCURSES)
150 mouse_set(BUTTON1_RELEASED);
158 /* game explanation -- initial help screen */
160 (void) waddstr(helpwin, "Knight's move is a solitaire puzzle. Your\n");
161 (void) waddstr(helpwin, "objective is to visit each square of the \n");
162 (void) waddstr(helpwin, "chessboard exactly once by making knight's\n");
163 (void) waddstr(helpwin, "moves (one square right or left followed \n");
164 (void) waddstr(helpwin, "by two squares up or down, or two squares \n");
165 (void) waddstr(helpwin, "right or left followed by one square up or\n");
166 (void) waddstr(helpwin, "down). You may start anywhere.\n\n");
168 (void) waddstr(helpwin, "Use arrow keys to move the cursor around.\n");
169 (void) waddstr(helpwin, "When you want to move your knight to the \n");
170 (void) waddstr(helpwin, "cursor location, press <space> or Enter.\n");
171 (void) waddstr(helpwin, "Illegal moves will be rejected with an \n");
172 (void) waddstr(helpwin, "audible beep.\n\n");
173 (void) waddstr(helpwin, "The program will detect if you solve the\n");
174 (void) waddstr(helpwin, "puzzle; also inform you when you run out\n");
175 (void) waddstr(helpwin, "of legal moves.\n\n");
177 MvWAddStr(helpwin, NOTIFYY - INSTRY, 0,
178 "Press `?' to go to keystroke help.");
183 /* keystroke help screen */
185 (void) waddstr(helpwin, "Possible moves are shown with `-'.\n\n");
187 (void) waddstr(helpwin, "You can move around with the arrow keys or\n");
188 (void) waddstr(helpwin, "with the rogue/hack movement keys. Other\n");
189 (void) waddstr(helpwin, "commands allow you to undo moves or redraw.\n");
190 (void) waddstr(helpwin, "Your mouse may work; try left-button to\n");
191 (void) waddstr(helpwin, "move to the square under the pointer.\n\n");
193 (void) waddstr(helpwin, "x,q -- exit y k u 7 8 9\n");
194 (void) waddstr(helpwin, "r -- redraw screen \\|/ \\|/ \n");
195 (void) waddstr(helpwin, "bksp -- undo move h-+-l 4-+-6\n");
196 (void) waddstr(helpwin, "a -- autojump /|\\ /|\\ \n");
198 (void) waddstr(helpwin, "R -- solve (slow) b j n 1 2 3\n");
200 (void) waddstr(helpwin, " b j n 1 2 3\n");
203 (void) waddstr(helpwin, "\nYou can place your knight on the selected\n");
204 (void) waddstr(helpwin, "square with spacebar, Enter, or the keypad\n");
205 (void) waddstr(helpwin, "center key. Use F/B to review the path.\n");
207 MvWAddStr(helpwin, NOTIFYY - INSTRY, 0,
208 "Press `?' to go to game explanation");
212 show_help(bool * keyhelp)
226 isValidYX(int y, int x)
228 return (y >= 0 && y < ylimit && x >= 0 && x < xlimit) ? TRUE : FALSE;
232 isUnusedYX(SQUARES squares, int y, int x)
234 return (isValidYX(y, x) && (!squares[y][x]) ? TRUE : FALSE);
238 boardIsFilled(SQUARES squares, int y, int x)
242 for (n = 0; n < MAX_OFFSET; n++) {
243 if (isUnusedYX(squares, y + offsets[n].y, x + offsets[n].x)) {
255 MvAddStr(0, 20, "KNIGHT'S MOVE -- a logical solitaire");
257 move(BOARDY, BOARDX);
258 waddch(boardwin, ACS_ULCORNER);
259 for (j = 0; j < (ylimit - 1); j++) {
260 waddch(boardwin, ACS_HLINE);
261 waddch(boardwin, ACS_HLINE);
262 waddch(boardwin, ACS_HLINE);
263 waddch(boardwin, ACS_TTEE);
265 waddch(boardwin, ACS_HLINE);
266 waddch(boardwin, ACS_HLINE);
267 waddch(boardwin, ACS_HLINE);
268 waddch(boardwin, ACS_URCORNER);
270 for (i = 1; i < ylimit; i++) {
271 move(BOARDY + i * 2 - 1, BOARDX);
272 waddch(boardwin, ACS_VLINE);
273 for (j = 0; j < xlimit; j++) {
274 waddch(boardwin, ' ');
275 waddch(boardwin, ' ');
276 waddch(boardwin, ' ');
277 waddch(boardwin, ACS_VLINE);
279 move(BOARDY + i * 2, BOARDX);
280 waddch(boardwin, ACS_LTEE);
281 for (j = 0; j < xlimit - 1; j++) {
282 waddch(boardwin, ACS_HLINE);
283 waddch(boardwin, ACS_HLINE);
284 waddch(boardwin, ACS_HLINE);
285 waddch(boardwin, ACS_PLUS);
287 waddch(boardwin, ACS_HLINE);
288 waddch(boardwin, ACS_HLINE);
289 waddch(boardwin, ACS_HLINE);
290 waddch(boardwin, ACS_RTEE);
293 move(BOARDY + i * 2 - 1, BOARDX);
294 waddch(boardwin, ACS_VLINE);
295 for (j = 0; j < xlimit; j++) {
296 waddch(boardwin, ' ');
297 waddch(boardwin, ' ');
298 waddch(boardwin, ' ');
299 waddch(boardwin, ACS_VLINE);
302 move(BOARDY + i * 2, BOARDX);
303 waddch(boardwin, ACS_LLCORNER);
304 for (j = 0; j < xlimit - 1; j++) {
305 waddch(boardwin, ACS_HLINE);
306 waddch(boardwin, ACS_HLINE);
307 waddch(boardwin, ACS_HLINE);
308 waddch(boardwin, ACS_BTEE);
310 waddch(boardwin, ACS_HLINE);
311 waddch(boardwin, ACS_HLINE);
312 waddch(boardwin, ACS_HLINE);
313 waddch(boardwin, ACS_LRCORNER);
317 mark_possibles(SQUARES squares, int y, int x, chtype mark)
321 for (n = 0; n < MAX_OFFSET; n++) {
322 if (isUnusedYX(squares, y + offsets[n].y, x + offsets[n].x)) {
323 cellmove(y + offsets[n].y, x + offsets[n].x);
324 waddch(boardwin, mark);
330 find_next_move(SQUARES squares, HISTORY * doneData, int doneSize, int *y, int *x)
336 int oldy = doneData[doneSize - 1].y;
337 int oldx = doneData[doneSize - 1].x;
342 for (j = 0; j < MAX_OFFSET * 2; j++) {
343 unsigned k = j % MAX_OFFSET;
344 int newy = oldy + offsets[k].y;
345 int newx = oldx + offsets[k].x;
346 if (isUnusedYX(squares, newy, newx)) {
352 } else if (found >= 0) {
361 *y = oldy + offsets[next].y;
362 *x = oldx + offsets[next].x;
370 count_next_moves(SQUARES squares, int count_moves, int y, int x)
375 wprintw(msgwin, "\nMove %d", count_moves);
376 for (j = 0; j < MAX_OFFSET; j++) {
377 int newy = y + offsets[j].y;
378 int newx = x + offsets[j].x;
379 if (isUnusedYX(squares, newy, newx)) {
383 wprintw(msgwin, ", gives %d choices", count);
388 unmarkcell(int row, int column)
390 cellmove(row, column);
391 waddch(boardwin, '\b');
392 waddch(boardwin, ' ');
393 waddch(boardwin, minus);
394 waddch(boardwin, ' ');
398 markcell(chtype tchar, int row, int column)
400 cellmove(row, column);
401 waddch(boardwin, '\b');
402 waddch(boardwin, tchar);
403 waddch(boardwin, tchar);
404 waddch(boardwin, tchar);
408 drawMove(SQUARES squares, int count_moves, chtype tchar, int oldy, int oldx, int
410 /* place the stars, update board & currents */
412 if (count_moves <= 1) {
415 for (i = 0; i < ylimit; i++) {
416 for (j = 0; j < xlimit; j++) {
417 if (count_moves == 0) {
421 if (winch(boardwin) == minus)
422 waddch(boardwin, ' ');
427 markcell(tchar, oldy, oldx);
428 mark_possibles(squares, oldy, oldx, ' ');
431 if (row >= 0 && column >= 0) {
432 markcell(trail, row, column);
433 mark_possibles(squares, row, column, minus);
434 squares[row][column] = TRUE;
437 wprintw(msgwin, "\nMove %d", count_moves);
438 if (count_tries != count_moves)
439 wprintw(msgwin, " (%d tries)", count_tries);
453 evaluate_move(SQUARES squares, HISTORY * doneData, int doneSize, int row, int column)
457 else if (squares[row][column] == TRUE) {
458 waddstr(msgwin, "\nYou've already been there.");
461 int rdif = iabs(row - doneData[doneSize - 1].y);
462 int cdif = iabs(column - doneData[doneSize - 1].x);
464 if (!((rdif == 1) && (cdif == 2)) && !((rdif == 2) && (cdif == 1))) {
465 waddstr(msgwin, "\nThat's not a legal knight's move.");
474 completed(SQUARES squares)
478 for (i = 0; i < ylimit; i++) {
479 for (j = 0; j < xlimit; j++) {
480 if (squares[i][j] != 0) {
485 return ((count == maxmoves) ? -1 : count);
489 no_previous_move(void)
491 waddstr(msgwin, "\nNo previous move.");
495 /* Recursively try all possible moves, starting from (y,x) */
497 recurBack(SQUARES squares, int y, int x, int total)
504 if (total < maxmoves) {
507 for (k = 0; k < MAX_OFFSET; k++) {
508 int try_x = x + offsets[k].x;
509 int try_y = y + offsets[k].y;
510 if (isUnusedYX(squares, try_y, try_x)) {
512 squares[try_y][try_x] = total + 1;
513 result = recurBack(squares, try_y, try_x, total + 1);
514 if (result > longest) {
519 if (result >= maxmoves)
521 squares[try_y][try_x] = 0; /* allow retry... */
527 if (longest > total) {
529 squares[best_y][best_x] = total + 1;
530 (void) recurBack(squares, best_y, best_x, total + 1);
531 if (result < maxmoves)
532 squares[best_y][best_x] = 0;
539 * Solve the Knight Tour problem using backtracking, returning the length of
540 * the resulting solution. If this is invoked from a point where the remaining
541 * choices cannot complete the tour, the result will fall short.
544 useBacktracking(SQUARES result, HISTORY * doneData, int doneSize)
549 int actual = doneSize - 1;
551 memset(squares, 0, sizeof(squares));
552 for (n = 1; n <= actual; ++n) {
558 total = recurBack(squares, y, x, actual);
559 if (total > actual) {
560 for (y = 0; y < ylimit; ++y) {
561 for (x = 0; x < xlimit; ++x) {
562 result[y][x] = squares[y][x];
563 if ((n = squares[y][x]) != 0) {
574 reviewHistory(HISTORY * history, int count_moves, int review, int *ny, int *nx)
579 } else if (review > count_moves - 2) {
581 review = count_moves - 2;
583 *ny = history[count_moves - review - 1].y;
584 *nx = history[count_moves - review - 1].x;
585 wprintw(msgwin, "\nReview %d:%d.", count_moves - review - 1,
596 bool keyhelp; /* TRUE if keystroke help is up */
598 int lastcol; /* last location visited */
601 int review = 0; /* review history */
603 int rw = 0, col = 0; /* current row and column */
607 HISTORY history[(YLIMIT * XLIMIT) + 1];
608 int count_moves = 0; /* count of moves so far */
610 /* clear screen and draw board */
616 wnoutrefresh(stdscr);
617 wnoutrefresh(helpwin);
618 wnoutrefresh(msgwin);
619 wnoutrefresh(boardwin);
622 for (i = 0; i < ylimit; i++) {
623 for (j = 0; j < xlimit; j++) {
627 memset(squares, 0, sizeof(squares));
628 memset(history, 0, sizeof(history));
629 history[0].y = history[0].x = -1;
630 history[1].y = history[1].x = -1;
631 lastrow = lastcol = -2;
638 if (rw != lastrow || col != lastcol) {
639 if (lastrow >= 0 && lastcol >= 0) {
640 cellmove(lastrow, lastcol);
641 if (squares[lastrow][lastcol])
642 waddch(boardwin, trail);
644 waddch(boardwin, oldch);
648 oldch = winch(boardwin);
654 waddch(boardwin, plus);
659 switch (wgetch(boardwin)) {
663 ny = rw + ylimit - 1;
676 nx = col + xlimit - 1;
687 ny = rw + ylimit - 1;
688 nx = col + xlimit - 1;
694 nx = col + xlimit - 1;
699 ny = rw + ylimit - 1;
711 #ifdef NCURSES_MOUSE_VERSION
716 if (myevent.y >= CY(0) && myevent.y <= CY(ylimit)
717 && myevent.x >= CX(0) && myevent.x <= CX(xlimit)) {
718 nx = CXINV(myevent.x);
719 ny = CYINV(myevent.y);
727 #endif /* NCURSES_MOUSE_VERSION */
732 test_y = MOUSE_Y_POS + 0;
733 test_x = MOUSE_X_POS + 1;
734 if (test_y >= CY(0) && test_y <= CY(ylimit)
735 && test_x >= CX(0) && test_x <= CX(xlimit)) {
738 wmove(helpwin, 0, 0);
744 #endif /* PDCURSES */
745 #endif /* KEY_MOUSE */
751 if (evaluate_move(squares, history, count_moves, rw, col)) {
755 history[count_moves - 1].y,
756 history[count_moves - 1].x,
758 history[count_moves].y = (short) rw;
759 history[count_moves].x = (short) col;
763 if (boardIsFilled(squares, rw, col)) {
764 if (completed(squares) < 0) {
765 waddstr(msgwin, "\nYou won.");
768 "\nNo further moves are possible.");
780 if (count_moves <= 0) {
782 } else if (count_moves <= 1) {
783 ny = history[count_moves].y;
784 nx = history[count_moves].x;
785 if (nx < 0 || ny < 0) {
786 ny = (lastrow >= 0) ? lastrow : 0;
787 nx = (lastcol >= 0) ? lastcol : 0;
790 squares[ny][nx] = FALSE;
792 drawMove(squares, count_moves, ' ', ny, nx, -1, -1);
797 int oldy = history[count_moves - 1].y;
798 int oldx = history[count_moves - 1].x;
800 if (!squares[rw][col]) {
802 waddch(boardwin, ' ');
805 squares[oldy][oldx] = FALSE;
807 ny = history[count_moves - 1].y;
808 nx = history[count_moves - 1].x;
809 if (nx < 0 || ny < 0) {
813 drawMove(squares, count_moves, ' ', oldy, oldx, ny, nx);
815 /* avoid problems if we just changed the current cell */
816 cellmove(lastrow, lastcol);
817 oldch = winch(boardwin);
824 if (find_next_move(squares, history, count_moves, &ny, &nx))
825 count_next_moves(squares, count_moves, ny, nx);
831 review = reviewHistory(history, count_moves, review - 1,
836 review = reviewHistory(history, count_moves, review + 1,
842 wprintw(msgwin, "\nworking...");
845 test_size = useBacktracking(squares, history, count_moves);
846 wprintw(msgwin, "\nOk %d:%d (%d tests)",
847 test_size, maxmoves, test_test);
849 while (count_moves <= test_size) {
851 ny = history[count_moves].y,
852 nx = history[count_moves].x);
856 wprintw(msgwin, "\nBoard is too large.");
865 clearok(curscr, TRUE);
866 wnoutrefresh(stdscr);
867 wnoutrefresh(boardwin);
868 wnoutrefresh(msgwin);
869 wnoutrefresh(helpwin);
892 if ((count = completed(squares)) < 0)
893 wprintw(msgwin, "\nYou won. Care to try again? ");
895 wprintw(msgwin, "\n%d squares filled. Try again? ", count);
898 (tolower(wgetch(msgwin)) == 'y');
904 static const char *msg[] =
906 "Usage: knight [options]"
910 #if HAVE_USE_DEFAULT_COLORS
911 ," -d invoke use_default_colors"
913 ," -n NUM set board-size to NUM*NUM (default 8x8)"
917 for (n = 0; n < SIZEOF(msg); n++)
918 fprintf(stderr, "%s\n", msg[n]);
920 ExitProgram(ok ? EXIT_SUCCESS : EXIT_FAILURE);
927 main(int argc, char *argv[])
931 while ((ch = getopt(argc, argv, OPTS_COMMON "dn:")) != -1) {
933 #if HAVE_USE_DEFAULT_COLORS
940 if (ch < 3 || ch > 8) {
941 fprintf(stderr, "board size %d is outside [3..8]\n", ch);
944 xlimit = ylimit = ch;
948 ExitProgram(EXIT_SUCCESS);
950 usage(ch == OPTS_USAGE);
962 ExitProgram(EXIT_SUCCESS);