The New Sudoku Players' Forum

[diggy]

My teacher showed us Sudoku games - he feels its a good thing for accounting students.

My problem is ::

What is a triple, a naked triple?

I can do and finish a game but have no idea what they are

HELP!!

[MCC]

diggy try clicking on this link.

http://forum.enjoysudoku.com/viewtopic.php?p=11308#p11308

[QBasicMac]

If still confused, maybe this will help:

A "Triple" is 3 cells in a given 9-cell (row, column, or box) which contain all of the occurrences of three candidate values. The simplest case would be {359}xx{359}x{359}xx where "x" are other cells not containing candidates 3,5, or 9.

But x{359}x{35}{59}xxxx would also be a triple

I guess technically, xx{359}xx{35}xx{35} would be a triple, but precedence would go to the two {35}'s (A double) and the fact of the triple would be ignored.

If the triple contains only the three candidates, it is called a "naked triple" otherwise it is called a "hidden triple". I might have chosen the term "exposed", rather than "naked" as the opposite of "hidden", but they are almost the same. Maybe "obvious" would be nice. But anyway, we are stuck with that term.

So who cares whether triples exist?

Take the case
x{2359}x{35}{589}xxxx

You can erase the pencilmarks 2 and 8, converting the hidden triple into the naked triple
x{359}x{35}{59}xxxx

And you can erase all occurences of 3, 5, and 9 in the other cells (x).

Those erasures may be sufficient to continue your solution.

Mac (with thanks to Myth Jellies)

[tso]

Err -- what's so special about naked triples that so many people are asking about it above all else suddenly? This is like the eleventy-sixth thread -- I know they're all newbies, but they've got to literally cover their eyes before asking so they won't accidently see the answer first.

[Myth Jellies]

Mac's reply, while true, was a little misleading about the usefulness of a naked triple. For example,

{386}{1}{359}{25}{4}{278}{35}{59}{2678}

is also a naked triple for the numbers 3, 5, and 9 in the third, seventh, and eighth cells. Even though these cells do not share both a box and a row or column, they are still useful, because you can eliminate the 3, 5, and 9 as possibilities in all of the other cells.

[QBasicMac]

Mac's reply, while true, ..."

Heh - actually kind of false. Thanks for checking it out in detail! It wasn't a typo. I was actually thinking at the time that the "in the box" additional criterion applied. I was probably confusing this with the case where a row in a box contained {58}x{35} and no other cell in the box has a 5. This would lead to my "you are so lucky" case that additional 5's are on the row outside the box that can be erased.

Anyway, the goof was so severe that I edited my post so unwary people don't get misled.

Thanks again,

Mac

Incorrect stuff removed from prior post:

Code: Select all

Then, for a naked triple, you might be so lucky that all 3 cells are in the same box plus on a single row or column. The cases are

1) The triple is true for a row. Then you can erase other occurrences of the three values that occur in the box.

2) The triple is true for a column. Similar to 1.

3) The triple is true for a box and they are in the same row. Then you can erase other occurrences of the three values that appear in that row.

4) The triple is true for a box and they are in the same column. Similar to 3.


[Cec]

Err -- what's so special about naked triples that so many people are asking about it .....

I can't resist this! I did mention in a previous thread - in jest of course -that newbies may get the wrong idea when reading about n*ke*d pairs and triples. Different terminology perhaps? No - let's retain it to keep the mystery intact.

Bonsai Cec

[Pat]

what's so special about naked triples that so many people are asking about it .....

I can't resist this! I did mention in a previous thread - in jest of course -that newbies may get the wrong idea when reading about n*ke*d pairs and triples. Different terminology perhaps? No - let's retain it to keep the mystery intact.

Bonsai Cec

my local theatre has now reserved Rows 1-9 for Naked Singles
{ link to Forum.EnjoySuDoku.com/viewtopic.php?p=10233#p10233 is now broken (lost post) and has been removed }

and the nearby Su Permaku has found shelf-space for a Skinny Dip

- Pat

[Cec]

OOh! You are naughty.

Bonsai Cec