| Version: | 2.8 |
| Date: | 2022-04-19 |
| Title: | Sudoku Puzzle Generator and Solver |
| Author: | David Brahm <brahm@alum.mit.edu> and Greg Snow <Greg.Snow@intermountainmail.org>, with contributions from Curt Seeliger <Seeliger.Curt@epamail.epa.gov> and Henrik Bengtsson <hb@maths.lth.se>. |
| Maintainer: | David Brahm <brahm@alum.mit.edu> |
| Suggests: | tkrplot |
| Description: | Generates, plays, and solves Sudoku puzzles. The GUI playSudoku() needs package "tkrplot" if you are not on Windows. |
| License: | GPL-2 | GPL-3 [expanded from: GPL] |
| NeedsCompilation: | no |
| Packaged: | 2022-04-19 14:11:47 UTC; David |
| Repository: | CRAN |
| Date/Publication: | 2022-04-19 14:30:02 UTC |
Fetch the daily sudoku puzzle from https://www.sudoku.org.uk/
Description
Fetches the daily sudoku puzzle from https://www.sudoku.org.uk/ or one of their archive from the previous 31 days.
Usage
fetchSudokuUK(day)
Arguments
day |
Optional character string specifying the day of the puzzle to download. This is in European date format 'dd/mm/yyyy' and needs to represent a date within the last 31 days. |
Value
A 9x9 matrix representing a sudoku puzzle (blank squares have value 0).
Note
See the website for copyright information. Don't submit your
solution for the prize contest if you used solveSudoku or
playSudoku with solve=TRUE. This function requires a
working internet connection.
Author(s)
Greg Snow greg.snow@intermountainmail.org
References
See Also
solveSudoku, playSudoku,
generateSudoku
Examples
## Not run:
#todays puzzle
puz <- fetchSudokuUK()
# puzzle from 25 Jan 2006 (if still available)
puza <- fetchSudokuUK('25/01/2006')
playSudoku(puza)
## End(Not run)
Randomly Generate a Sudoku Puzzle Grid
Description
Creates a 9x9 Sudoku grid suitable for use by
playSudoku.
Usage
generateSudoku(Nblank=50, print.it=FALSE)
Arguments
Nblank |
Number of cells to blank out |
print.it |
Logical. If true, print result to screen. |
Details
The basic algorithm is to start with a 'primordial' Sudoku grid, swap around some rows and columns, then blank out some cells.
Value
A matrix, representing a 9x9 Sudoku grid.
Author(s)
Curt Seeliger <Seeliger.Curt@epamail.epa.gov>, Henrik Bengtsson <hb@maths.lth.se>, and David Brahm <brahm@alum.mit.edu>
References
Examples
generateSudoku(print.it=TRUE)
Give a Hint for a Sudoku Cell
Description
Generates a text string containing a 'hint' for cell (i,j) of Sudoku grid 'z'.
Usage
hintSudoku(z, i, j)
Arguments
z |
A 9x9 numeric matrix |
i |
Row index |
j |
Column index |
Value
A character string, suitable for cat.
Author(s)
Greg Snow greg.snow@intermountainmail.org and David E. Brahm <brahm@alum.mit.edu>
Interactively play a game of Sudoku
Description
Interactively play a game of 9x9 Sudoku with hints and undo
Usage
playSudoku(z=NULL, hist.len=100, solve=TRUE,
display=c("guess","windows","tk"),
hscale=1.25, vscale=1.25, ...)
Arguments
z |
Either a 9x9 numeric matrix representing the Sudoku grid
(with '0' representing a blank cell), or 0 (zero) for an empty
matrix, or a filename (passed to |
hist.len |
Integer representing the number of history steps to remember (number of undo's possible). |
solve |
Logical indicating if the solution should be computed (used for checking current answer or cheating). |
display |
Type of display. The default 'guess' uses a windows graphics device if getOption('device')=='windows', otherwise it uses tk (requiring the 'tkrplot' package). |
hscale |
Passed to tkrplot |
vscale |
Passed to tkrplot |
... |
Arguments passed to |
Details
To play, move the mouse arrow over an empty cell and press the number key to enter the number in the cell. Typing '?' brings up a menu of additional commands:
? -- a short help message
1-9 -- insert digit
0,' ' -- clear cell
r -- replot the puzzle
q -- quit
h -- hint/help
c -- correct wrong entries (show in red)
u -- undo last entry
s -- show number in cell
a -- show all (solve the puzzle)
Value
An invisible matrix with the solution or current state of the puzzle. Save this if you stop part way through, and use it as the input for the function to start again where you left off (undo info is lost so make sure that everything is correct).
Note
display='windows' makes use of the getGraphicsEvent
function, which currently only works on Windows.
Author(s)
Greg Snow greg.snow@intermountainmail.org and David E. Brahm <brahm@alum.mit.edu>
See Also
Examples
## Not run:
puz1 <- playSudoku(0) # Use as an editor to create a puzzle, then quit
sol1 <- playSudoku(puz1) # now play the puzzle
puz2 <- edit(matrix(0,9,9)) # Or use this editor
sol2 <- playSudoku(puz2) # now play the puzzle
playSudoku() # Play a randomly generated game
playSudoku(fetchSudokuUK()) # Play today's game
## End(Not run)
Print a Sudoku Grid to the Terminal.
Description
Prints a Sudoku grid (a 9x9 matrix) to the terminal.
Usage
printSudoku(z)
Arguments
z |
A 9x9 numeric matrix, with '0' representing a blank cell. |
Value
None; used for side effect.
Author(s)
David E. Brahm <brahm@alum.mit.edu>
Read a File Containing a Sudoku Grid
Description
Reads a file containing a Sudoku grid (a 9x9 matrix).
Usage
readSudoku(fn, map)
Arguments
fn |
A filename. |
map |
Vector of unique puzzle elements (possibly longer than
necessary). The default is |
Details
The input file should look like this:
-6-1-4-5- --83-56-- 2-------1 8--4-7--6 --6---3-- 7--9-1--4 5-------2 --72-69-- -4-5-8-7-
Blank cells can be indicated with any character not in "map", such as the '-' used here.
Value
A numeric matrix (usually 9x9).
Author(s)
David E. Brahm <brahm@alum.mit.edu>
Examples
z <- readSudoku(system.file("puz1.txt", package="sudoku"))
Solve a Sudoku Puzzle
Description
Solves a Sudoku Puzzle.
Usage
solveSudoku(z, verbose=FALSE, map=c(1:9,letters), level=0,
print.it=TRUE)
Arguments
z |
A filename (passed to |
verbose |
If TRUE, report on progress. |
map |
Vector of unique puzzle elements (possibly longer than
necessary). The default is |
level |
Recursion level (should not be set by user). |
print.it |
Logical: print the solution? |
Details
A Sudoku puzzle consists of an NxN grid, where N is a perfect square (usually N=9). The grid is subdivided into N [sqrt(N) x sqrt(N)] boxes. You must fill in the missing values so that each row, each column, and each box contains the integers 1:N exactly once.
The algorithm uses an NxNxN array of logicals, representing the NxN cells and the N possible elements. For example, if a[1,2,3]=TRUE, then z[1,2] is known to be '3'. If a[1,2,4]=FALSE, then z[1,2] is known not to be '4'. The basic rules of Sudoku are used to fill in FALSE's, then elimination is used to find the TRUE's. If that approach runs out of steam, a guess is made and the program recurses to find either a solution or an inconsistency. No attempt is made to prove a solution's uniqueness.
Value
Invisibly returns the solved (numerical) matrix, and prints the character version.
Author(s)
David E. Brahm <brahm@alum.mit.edu>
References
Example "puz1" comes from https://sudoku.com/.
Examples
## Not run:
solveSudoku(system.file("puz1.txt",package="sudoku"), verbose=TRUE)
## End(Not run)
Write a Sudoku Grid to a File
Description
Writes a Sudoku grid (a matrix) to a file.
Usage
writeSudoku(z, fn)
Arguments
z |
A Sudoku grid. |
fn |
A filename. |
Value
None; used for its side effect.
Author(s)
David E. Brahm <brahm@alum.mit.edu>