X-Treme Dec 10

Welcome to the world of the unknown. Each day you need to solve <a href="http://www.sudocue.net/xfile.php">two mysteries</a>.<br>Take the X-R-Size or solve the X-Treme problem. Stuck? Found a nice solution? Tell us about it.
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emm
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X-Treme Dec 10

Post by emm »

Any hints for getting over this hump?

4 or 9 must be in r5c89 but how to figure this out without using brute force?

Code: Select all

+---------------+---------------+------------------+ 
| 2   3    6    |  5   9   1   | 8    7      4     | 
| 49  1    49   |  8   2   7   | 5    6      3     | 
| 5   8    7    |  3   6   4   | 9    12     12    | 
+---------------+--------------+-------------------+ 
| 8   45   129  |  6   14  3   | 12   12459  7     | 
| 69  246  1239 |  7   8   5   | 36   1249   129   | 
| 7   456  13   |  2   14  9   | 36   145    8     | 
+---------------+--------------+-------------------+ 
| 3   69   5    |  1   7   2   | 4    8      69    | 
| 46  7    24   |  9   5   8   | 12   3      126   | 
| 1   29   8    |  4   3   6   | 7    29     5     | 
+---------------+--------------+-------------------+
Ruud
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Post by Ruud »

There is an XY-chain that eliminates digit 9 from r5c9:

Code: Select all

&#40;9=6&#41;r7c9-&#40;6=9&#41;r7c2-&#40;9=2&#41;r9c2-&#40;2=4&#41;r8c3-&#40;4=6&#41;r8c1-&#40;6=9&#41;r5c1
if you prefer it in Nice Loop notation:

Code: Select all

&#91;r5c9&#93;-9-&#91;r7c9&#93;-6-&#91;r7c2&#93;-9-&#91;r9c2&#93;-2-&#91;r8c3&#93;-4-&#91;r8c1&#93;-6-&#91;r5c1&#93;-9-&#91;r5c9&#93; => &#91;r5c9&#93;<>9
It's singles all the way from there.

Ruud
“If the human brain were so simple that we could understand it, we would be so simple that we couldn't.” - Emerson M Pugh
emm
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Post by emm »

Thanks :)
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