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oaxen
Joined: 10 Jul 2006 Posts: 96
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Posted: Tue Aug 22, 2006 6:51 pm Post subject: august 18 very hard |
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After solving the "easy ones (20 units)"I got stucked and asked for a hint.
received "5" on c8r3. Why? I canīt see the logic in that choice. Can somebody tell me or do I have to write down the situation as far as I got
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TKiel
Joined: 22 Feb 2006 Posts: 292 Location: Kalamazoo, MI
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Posted: Wed Aug 23, 2006 2:37 am Post subject: |
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If I've done this right, at that point in the puzzle the candidates for r3c8 are 2, 5 & 8. There is an X-wing on 2 in row 6 & 7 that removes that digit and the 8 can be excluded because the 8 in row 2 must be in box 3 (which I think would make it a box/box interaction) and can thus be excluded from all other cells in that same box. |
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oaxen
Joined: 10 Jul 2006 Posts: 96
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Posted: Wed Aug 23, 2006 7:06 am Post subject: |
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Thank you Tracy, that was not too easy to find out
Lars/Oaxen |
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Golfgal
Joined: 31 Jul 2006 Posts: 7
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Posted: Wed Aug 23, 2006 11:33 am Post subject: 8/18 |
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found the x-wing BUT unsure of what 2 in boxes 3, 6 & 9 could be removed
this is what i have
700 020 361
140 763 {289}{2589}{28}
306 900 4{25}7
238 679 514
400 000 {268}{238}{268}
651 048 7{23}9
064 007 1{29}3
000 130 {689}4{68}
813 090 {26}75 |
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TKiel
Joined: 22 Feb 2006 Posts: 292 Location: Kalamazoo, MI
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Posted: Wed Aug 23, 2006 12:00 pm Post subject: |
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This is the point at which the X-wing occurred.
Code: |
*-----------------------------------------------------------*
| 7 89 59 | 458 2 45 | 3 6 1 |
| 1 4 259 | 7 6 3 | 289 2589 28 |
| 3 28 6 | 9 158 15 | 4 258 7 |
|-------------------+-------------------+-------------------|
| 2 3 8 | 6 7 9 | 5 1 4 |
| 4 79 79 | 235 15 125 | 268 238 268 |
| 6 5 1 |[23] 4 8 | 7 [23] 9 |
|-------------------+-------------------+-------------------|
| 59 6 4 |[258] 58 7 | 1 [289] 3 |
| 59 279 2579 | 1 3 256 | 2689 4 268 |
| 8 1 3 | 24 9 246 | 26 7 5 |
*-----------------------------------------------------------*
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All the 2's in columns 4 & 7 can be excluded, except the ones that have brackets. I'm not sure why the hint didn't indicate that r9c4 would have to be 4, which seems a more obvious move than the one given. Probably the order in which techniques are implemented and it would have already found the box/box interaction and excluded the 8 from r3c8. |
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Golfgal
Joined: 31 Jul 2006 Posts: 7
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Posted: Wed Aug 23, 2006 12:23 pm Post subject: |
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Tracey,
So obvious when the answer is presented.......Thank You |
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