| Paul
| Joined: 11 Aug 2005 | Posts: 29 | : | | Items |
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Posted: Wed Jan 11, 2006 5:26 pm Post subject: Hidden single, or single hidden subset? |
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I was testing some puzzles against my solver, and came across this one which got it stumped. It's so simple, i can't believe i missed this!
Code: | 4.6|.5.|12.
...|4..|..8
.92|...|.7.
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.2.|.8.|...
7..|1.3|..6
...|.9.|.4.
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.1.|...|56.
2..|..5|...
.45|.1.|3.2 |
If you look at column 5, then the candidates are:
{5}{2,3,6,7}{3,6}{8}{2,4}{9}{2,3,4}{3,4,6}{1}
Obviously, since the number 7 only appears once in this column, it must be in the second cell.
My question is: Is this a hidden single, or a single hidden subset? Or would you class both as being the same? |
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| gaby
| Joined: 02 Jul 2005 | Posts: 120 | : | | Items |
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Posted: Wed Jan 11, 2006 6:08 pm Post subject: |
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A hidden subset is a set of N numbers that only appear in N cells between them, and nowhere else. So a hidden subset of size 1 would be 1 number appearing in 1 cell in a house and nowhere else.
Hidden singles, hidden subset where N=1, they're the same thing. _________________ Free daily sudoku - Online puzzle database
http://vanhegan.net/sudoku/ |
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