Northwest Airlines Sudoku Puzzles

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Northwest Airlines Sudoku Puzzles

Postby daj95376 » Mon Aug 11, 2008 7:51 pm

In the DailySudoku forum, there's a question about solving an NWA Sudoku puzzle. If you belong to that forum, you might inform everyone that NWA Sudoku puzzles have extra constraints where four shaded boxes/regions must also have 1-9. This explains why vanilla Sudoku responds with multiple solutions.

Code: Select all
 Shaded Regions
 +-----------------------+
 | . . . | . . . | . . . |
 | . X X | X . X | X X . |
 | . X X | X . X | X X . |
 |-------+-------+-------|
 | . X X | X . X | X X . |
 | . . . | . . . | . . . |
 | . X X | X . X | X X . |
 |-------+-------+-------|
 | . X X | X . X | X X . |
 | . X X | X . X | X X . |
 | . . . | . . . | . . . |
 +-----------------------+

NWA Sudoku puzzles have appeared in this forum as well.

http://forum.enjoysudoku.com/viewtopic.php?p=55881#p55881
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Postby Glyn » Tue Aug 12, 2008 12:17 am

In fact it is worth mentioning that this form of puzzle, which is more commonly called NRC or Windoku, with the 4 extra explicit shaded regions labelled E,F,H and I, also contains 5 more hidden implicit regions A,B,C,D,G which must contain the digits 1-9. The total of 9 extra regions gives further information useful in solving these problems and in allowing the number of clues to be as low as 11.

Code: Select all
+-----------------------+
 | A B B | B A C | C C A |
 | D E E | E D F | F F D |
 | D E E | E D F | F F D |
 |-------+-------+-------|
 | D E E | E D F | F F D |
 | A B B | B A C | C C A |
 | G H H | H G I | I I G |
 |-------+-------+-------|
 | G H H | H G I | I I G |
 | G H H | H G I | I I G |
 | A B B | B A C | C C A |
 +-----------------------+
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Postby daj95376 » Fri Aug 15, 2008 1:09 pm

I passed Glyn's comment, about the puzzle being a Windoku, to NWA. I suggested that the puzzle be labeled Windoku instead of Sudoku. They passed my suggestion along to the publishers of their WorldTraveler magazine. The publisher's reply:

Danny,

Thank you for note. We apologize for the confusion. We are replacing the current puzzle with a traditional Sudoku in the September issue. Thanks again for taking the time to express your concern.

Frank Sisser

Side Note: I find it interesting that no one took the time to update the misinformation being passed around in the DailySudoku thread.
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Postby Pat » Sun Aug 17, 2008 5:12 am

daj95376 wrote:I find it interesting that no one took the time to update the misinformation being passed around in the DailySudoku thread.



this is the link to their discussion -- "Northwest Airlines"
    but we don't have many representatives active in that forum
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