Solving with colors

Advanced methods and approaches for solving Sudoku puzzles

Solving with colors

Postby reallyjoel » Tue Jul 19, 2005 12:53 am

This is as far as I got with a sudoku in Simple Sudoku

..3|...|...
7..|98.|.16
.1.|.73|...
-----------
3.4|8..|9..
19.|...|.58
..8|..6|4.1
-----------
...|34.|.2.
24.|.19|..3
...|...|7..


..3|1..|...
752|984|316
.1.|.73|...
-----------
3.4|851|9..
19.|43.|.58
5.8|.96|431
-----------
...|34.|12.
24.|.19|..3
.31|...|7..


[49] [68] [3] [1] [26] [25] [258] [479] [479]
[7] [5] [2] [9] [8] [4] [3] [1] [6]
[4689] [1] [69] [256] [7] [3] [258] [489] [2459]
[3] [26] [4] [8] [5] [1] [9] [67] [27]
[1] [9] [67] [4] [3] [27] [26] [5] [8]
[5] [27] [8] [27] [9] [6] [4] [3] [1]
[689] [678] [5679] [3] [4] [578] [1] [2] [59]
[2] [4] [57] [567] [1] [9] [568] [68] [3]
[89] [3] [1] [256] [26] [258] [7] [469] [459]

Now the hint it gives are about Colors. I don't understand it, could anyone explain it?
reallyjoel
 
Posts: 8
Joined: 14 July 2005

Re: Solving with colors

Postby angusj » Tue Jul 19, 2005 2:01 am

reallyjoel wrote:This is as far as I got with a sudoku in Simple Sudoku ...
Now the hint it gives are about Colors. I don't understand it, could anyone explain it?


Filter on the 7s, and then apply colors (Blue & Green will do fine) to conjugate cells as per the following ...

Code: Select all
...|...|...
...|...|...
...|...|...
-----------
...|...|...
..B|..G|...
...|...|...
-----------
...|..B|...
..B|G..|...
...|...|...

You'll see that there a 2 B's (representing either the 'true' of 'false' state) in column 3. Because there can't be 2 'trues' in one group the Bs must represent 'false'. Therefore you can exclude 7 from all B cells and conversely assign 7 to a G cells.

See also: http://angusj.com/sudoku/hints.php#colors
angusj
 
Posts: 306
Joined: 12 June 2005


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