1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
|
<HTML>
<HEAD>
<TITLE>Sudoku Manual Page</TITLE>
</HEAD>
<BODY>
<PRE>
</PRE>
<H2>SYNOPSIS</H2><PRE>
(play the game)
<B>sudoku</B> [<I>options</I>] ... [<I><filename></I>]
(generate boards)
<B>sudoku</B> <B>-g</B> [<I><num></I>] [<I>options</I>] ...
(solve boards)
<B>sudoku</B> <B>-v</B> [<I>options</I>] ...
(calculate statistics)
<B>sudoku</B> <B>-s</B> [<I>options</I>] ...
</PRE>
<H2>DESCRIPTION</H2><PRE>
The <B>sudoku</B> board game is played on a 9x9 grid, divided into rows, col-
umns, and 9 blocks of 3x3 squares. The objective is to fill the empty
squares with the digits 1-9, so that each row, column, and block con-
tains each of the digits 1-9 (and hence, it is not possible for any
digit to appear twice in the same row, column or block).
</PRE>
<H2>EXAMPLE</H2><PRE>
Consider the following board, and the squares marked `<I>a</I>'-`<I>h</I>' and `<I>x</I>':
5 . <I>a</I> | 6 <I>b</I> 1 | . . . The digits appearing in each of the
7 9 . | . . . | <I>c</I> 6 8 squares `<I>a</I>'-`<I>h</I>' can be uniquely
<I>d</I> 3 . | . 8 . | 7 . . determined. For example, the value
-------+-------+------- at `<I>a</I>' must be 8, since an 8 appears
. 5 . | 4 1 <I>e</I> | . . 2 in the other rows and columns of the
. . 1 | <I>f</I> <I>x</I> . | 6 . . block. Using similar logic, it must
8 . . | . 3 7 | . 4 . be true that:
-------+-------+------- <I>b</I> = 7 <I>f</I> = 8
. . 4 | . 9 . | <I>g</I> 2 . <I>c</I> = 1 <I>g</I> = 8
2 8 <I>h</I> | . . . | . 9 7 <I>d</I> = 1 <I>h</I> = 5
. . . | 5 <I>i</I> 8 | . . 6 <I>e</I> = 6 <I>i</I> = 2
In contrast, it is not possible to uniquely determine the value of `<I>x</I>'
with the given information - it could take either the value 2 or 5.
The board now contains the squares:
5 . 8 | 6 7 1 | . . . It is now possible to determine the values
7 9 . | . . . | 1 6 8 appearing in other empty squares.
1 3 . | . 8 . | 7 . .
-------+-------+-------
. 5 . | 4 1 6 | . . 2
. . 1 | 8 <I>x</I> . | 6 . . <<< the value of <I>x</I> must now be 5.
8 . . | . 3 7 | . 4 .
-------+-------+-------
. . 4 | . 9 . | 8 2 .
2 8 5 | . . . | . 9 7
. . . | 5 2 8 | . . 6
Repeating this process a few more times reveals the solution:
5 4 8 | 6 7 1 | 2 3 9
7 9 2 | 3 4 5 | 1 6 8
1 3 6 | 9 8 2 | 7 5 4
-------+-------+-------
3 5 7 | 4 1 6 | 9 8 2
4 2 1 | 8 5 9 | 6 7 3
8 6 9 | 2 3 7 | 5 4 1
-------+-------+-------
6 1 4 | 7 9 3 | 8 2 5
2 8 5 | 1 6 4 | 3 9 7
9 7 3 | 5 2 8 | 4 1 6
</PRE>
<H2>GAME INTERFACE</H2><PRE>
The <B>sudoku</B> game has a simple text interface (using the <B>curses(3)</B>
library). The board is displayed in the middle of the screen, along
with a summary of the allowed key presses. The cursor can be moved
around the board using the arrow keys or the standard <B>vi(1)</B> movement
keys, and each square (except for the fixed board squares that are ini-
tially revealed) can be set to a given digit by pressing the corre-
sponding number key, or cleared by pressing either the `<I>0</I>' or `<I>.</I>'
keys.
<B>Generating</B> <B>a</B> <B>New</B> <B>Board</B>
A new board can be generated at any time by pressing the `<I>n</I>' key, and
either a <I>precanned</I> or randomly generated board will be displayed. If
the <B>-n</B> command line option is set, then only <I>precanned</I> boards will be
displayed.
<B>Entering</B> <B>a</B> <B>Custom</B> <B>Board</B>
A custom board (e.g. found on the internet, or published in a newspa-
per) can be entered into the game by first clearing the current board
(press the `<I>c</I>' key), entering the published squares (using the cursor
motion keys and entering the appropriate numbers), and then fixing the
squares by pressing the `<I>f</I>' key. At this point, the entered squares
will be fixed (and cannot be changed).
<B>Hints</B>
The interactive game provides a simple hint mechanism to provide assis-
tance in solving the board. It attempts to highlight areas of the board
where moves can be made. If repeated hints are requested, the system
starts revealing the digit that can be placed on the board.
Often the hints can be quite cryptic. For example, consider the board
below:
v v v
. . 7 | . . <B>9</B> | . . .
<B>9</B> . <B>6</B> | 7 <B>4</B> . | . <B>1</B> <B>5</B>
. . <B>2</B> | <B>5</B> <B>1</B> . | . . .
-------+-------+-------
> <B>6</B> . <B>5</B> | . 7 . | . . <B>8</B> < <I>The</I> <I>characters</I> <I>><v^</I> <I>highlight</I> <I>the</I>
> . <B>7</B> . | . . . | . <B>3</B> . < <I>area</I> <I>of</I> <I>the</I> <I>hint</I>
> <B>8</B> . . | . . . | <B>7</B> . <B>6</B> <
-------+-------+-------
. . . | . <B>6</B> <B>7</B> | <B>8</B> . .
<B>7</B> <B>4</B> . | . <B>5</B> . | <B>9</B> 6 <B>2</B>
. 6 . | <B>4</B> . . | . . .
^ ^ ^
The system gives the hint `<I>try</I> <I>the</I> <I>digit</I> <I>3</I>', but it is certainly not
obvious, with the revealed squares, where the 3 goes.
</PRE>
<H2>OPTIONS</H2><PRE>
<B>-c</B><I><class></I>
Generate a board until it finds a board of the specified class.
Supported classes are: very easy, easy, medium, hard, and fiendish.
<B>-d</B> Describe the moves needed to solve the board. Can only be used
with the <B>-v</B> option for solving <I>precanned</I> boards.
<B>-f</B><I><format></I>
Set output format. The supported formats are:
<B>standard</B> Default text format; <B>std</B> is a shortcut.
<B>compact</B> Compact text format.
<B>csv</B> Comma separated values, suitable for importing
into a spreadsheet.
<B>postscriptps</B> is a shortcut.
<B>html</B> Simple HTML.
<B>-g</B><I>[<num>]</I>
Generate <I><num></I> boards (or just 1 board, if not specified) and
write them to standard output.
<B>-n</B> No random boards generated in the interactive game. Requires the
optional file of <I>precanned</I> boards to be specified.
<B>-r</B> Run in restricted mode, disallowing any games to be saved.
<B>-s</B> Calculate statistics for the <I>precanned</I> boards, and attempt to
classify the difficulty of solving the boards. Can be used with
the <B>-v</B> option.
<B>-t</B><I><filename></I>
Set the template file. The file set on the command line will be
used instead of the default template file.
<B>-v</B> Solve <I>precanned</I> boards, writing the solution to standard output.
<I><filename></I>
Name of the optional file containing <I>precanned</I> boards.
<B>-w</B> Write <I>default template</I> to the working directory if it doesn't
exist yet.
</PRE>
<H2>ENVIRONMENT</H2><PRE>
No environment variables are used directly by the <B>sudoku</B> program.
</PRE>
<H2>FILES</H2><PRE>
<B>/usr/share/sudoku/template</B>
Template file for generating new sudoku boards.
<B>/usr/share/sudoku/precanned</B>
Optional file, containing `precanned' sudoku boards.
</PRE>
<H2>FILE FORMATS</H2><PRE>
<B>/usr/share/sudoku/template</B>
The template file contains a sequence of patterns that are used for
generating new <B>sudoku</B> boards. Each pattern is started by a line with a
leading `%' character, and consists of 9 lines of 9 characters. The
character `.' represents a square that is initially blank, and the
character `*' represents a square with a digit that is initially dis-
played.
<B>Compact</B> <B>text</B> <B>format</B>
This format is similar to that of the template file, but contains rep-
resentations of game boards. Each board is started by a line with a
leading `%' character, followed by an optional title for the board that
is displayed when the game is played. This is followed by 9 lines of 9
characters, where the character `.' represents an initially empty
square, and the characters `1'-`9' give the value of a fixed board
square that is initially displayed. The <B>sudoku</B> program can read pre-
canned files in this format, and will write them when the <B>-fcompact</B>
option is set.
<B>Standard</B> <B>text</B> <B>format</B>
This format is very similar to the compact text format, but includes
additional characters to delimit the blocks in the board. The <B>sudoku</B>
program can read precanned files in this format, and writes them by
default, unless another output format is set by the <B>-f</B> option.
<B>Comma</B> <B>separated</B> <B>text</B> <B>format</B>
This format is useful for importing <B>sudoku</B> boards into a spreadsheet.
It represents each board by 9 lines of comma separated fields. Each
field is blank, or contains a digit. The <B>sudoku</B> program cannot read
precanned files in this format, and writes them when the <B>-fcsv</B> option
is set. Unlike the standard or compact text formats, there are no lines
separating boards, and hence, it is really only feasible to store one
board per file.
<B>Postscript</B> <B>format</B>
This format is useful for printing out <B>sudoku</B> boards. The <B>sudoku</B> pro-
gram cannot read boards stored in this format, and writes them when the
<B>-fpostscript</B> option is set. Unlike the standard or compact text for-
mats, it is not possible to store multiple boards in the same file.
<B>HTML</B> <B>format</B>
This format is useful for printing out <B>sudoku</B> boards. The <B>sudoku</B> pro-
gram cannot read boards stored in this format, and writes them when the
<B>-fhtml</B> option is set. Unlike the standard or compact text formats, it
is not possible to store multiple boards in the same file.
</PRE>
<H2>SEE ALSO</H2><PRE>
There are a large number of websites dedicated to the <B>sudoku</B> puzzle
that can be found easily using a search engine. Some of these sites
provide game boards that can be challenging to solve, and others pro-
vide strategies for finding moves.
</PRE>
<H2>DIAGNOSTICS</H2><PRE>
There are limited diagnostics available when an error occurs.
</PRE>
<H2>ACKNOWLEDGEMENTS</H2><PRE>
Mark Foreman for the HTML output format; Joanna Ferris and Heather for
encouraging this endeavour.
</PRE>
<H2>AUTHOR</H2><PRE>
Michael Kennett (mike@laurasia.com.au)
</PRE>
<H2>COPYRIGHT</H2><PRE>
This manual page, and all associated files, have been placed into the
public domain by Michael Kennett, July 2005. They may be used by any-
body for any purpose whatsoever, however <B>NO</B> <B>WARRANTY</B>, of any sort,
applies to this work.
</PRE>
<HR/>
</BODY>
</HTML>
|
