The New Sudoku Players' Forum

[opticdazzle]

here is my puzzle...although there is the answer sheet in the back pages of my book, i'd like some explanation as how to solve the puzzle from where i stay blocked...i will provide the original puzzle then provide my predicament...

the beginning

7,1,5,5,,9
,,,,,,274
39,,,,,,,
,,,,,,598
,,,1,8,,,
876,,,,,,
,,,,,,,52
659,,,,,,
,,,7,94,3


here is my problem:

721546839
568,,,274
394,,,615
213,,,598
945138726
876,,5341
437,,,952
659,,,187
182759463[/code]

[vidarino]

Code: Select all

7 2 1 5 4 6 8 3 9
5 6 8 , , , 2 7 4
3 9 4 , , , 6 1 5
2 1 3 , , , 5 9 8
9 4 5 1 3 8 7 2 6
8 7 6 , , 5 3 4 1
4 3 7 , , X 9 5 2
6 5 9 , X , 1 8 7
1 8 2 7 5 9 4 6 3


The spots marked with X'es can only have one specific value.

[QBasicMac]

Your original puzzle was a bit messed up on line one. Here is my guess.

Code: Select all

+-----------------+---------------------+----------------+
| 7    24    1    | 5     2348     6    | 38    38    9  |
| 5    6     8    | 39    139      13   | 2     7     4  |
| 3    9     24   | 248   2478     247  | 6     1     5  |
+-----------------+---------------------+----------------+
| 124  1234  234  | 2346  23467    2347 | 5     9     8  |
| 249  234   2345 | 1     2345679  8    | 37    2346  67 |
| 8    7     6    | 2349  23459    2345 | 13    234   1  |
+-----------------+---------------------+----------------+
| 14   1348  347  | 3468  13468    134  | 1789  5     2  |
| 6    5     9    | 2348  12348    1234 | 178   8     17 |
| 12   128   2    | 7     12568    9    | 4     68    3  |
+-----------------+---------------------+----------------+


The puzzle is easily solved by just by continuing the technique you were using. You got correctly to here:

Code: Select all

+---------+---------------+---------+
| 7  2  1 | 5    4    6   | 8  3  9 |
| 5  6  8 | 39   19   13  | 2  7  4 |
| 3  9  4 | 28   278  27  | 6  1  5 |
+---------+---------------+---------+
| 2  1  3 | 46   67   47  | 5  9  8 |
| 9  4  5 | 1    3    8   | 7  2  6 |
| 8  7  6 | 29   29   5   | 3  4  1 |
+---------+---------------+---------+
| 4  3  7 | 68   168  1   | 9  5  2 |
| 6  5  9 | 234  2    234 | 1  8  7 |
| 1  8  2 | 7    5    9   | 4  6  3 |
+---------+---------------+---------+


so I am surprised you are now stuck. That was good work.

Look at row 8, column 5 (r8c5).
It can't be 659187 (row 8 already populated)
It can't be 435 (column 5 already populated)
It can't be 759 (box 8 already populated)
That leave 2. Put it in.

Now look at r6c5.
Not 8765341 (row)
Not 4325 (column)
Not 1385 (box)
That leaves 9.

By the same token, r2c5 now has to be a 1.
The same with r2c6, etc.

Mac

[opticdazzle]

Thanks ya'll