The New Sudoku Players' Forum

by **amirzadeh** » Wed Sep 20, 2006 5:48 pm

Hello all,

Original Puzzle

Code: Select all: *--------------------------------------------------------------------* | - - 6 | - - - | 9 8 3 | | - - - | - - 1 | - - - | | - - 4 | - 9 - | - - - | |----------------------+----------------------+----------------------| | - - 2 | - - - | - 4 - | | - - 3 | 6 7 - | 8 - 1 | | 6 - - | - - 4 | - - - | |----------------------+----------------------+----------------------| | - - - | 7 - - | - - - | | - - - | 5 - - | - - 2 | | 9 - 5 | - 6 8 | 4 - - | *--------------------------------------------------------------------*

Solution so far:

Code: Select all: *--------------------------------------------------------------------* | 125 125 6 | 4 25 7 | 1 5 8 | | 235 23578 9 | 238 2358 1 | 26 267 4 | | 123 12378 4 | 238 9 6 | 12 127 5 | |----------------------+----------------------+----------------------| | 8 15 2 | 9 135 35 | 7 4 6 | | 4 9 3 | 6 7 25 | 8 25 1 | | 6 15 7 | 1238 12358 4 | 23 235 9 | |----------------------+----------------------+----------------------| | 23 6 1 | 7 4 23 | 5 9 8 | | 7 4 8 | 5 13 9 | 136 136 2 | | 9 23 5 | 123 6 8 | 4 13 7 | *--------------------------------------------------------------------*

I am stuck at this point. I have been trying to read along the past forum posts but my not knowing the terminology is not helping. I don't understand the referneces and can't deduct the logic behind some of the answers people have provided. So if you have a solution some backgroun d would be great.

If anyone can help it would be greatly appreciated.

Thanks

Aram

by **gsf** » Wed Sep 20, 2006 5:59 pm

the pencilmark grid does not match the original grid
e.g., look at the top right box

by **Steve R** » Thu Sep 21, 2006 2:07 am

Also, according to the computer, the starting puzzle, as posted, has 35 solutions.

Steve

by **Pat** » Thu Sep 21, 2006 10:09 am

amirzadeh wrote:Original Puzzle
Code: Select all
*--------------------------------------------------------------------* | - - 6 | - - - | 9 8 3 | | - - - | - - 1 | - - - | | - - 4 | - 9 - | - - - | |----------------------+----------------------+----------------------| | - - 2 | - - - | - 4 - | | - - 3 | 6 7 - | 8 - 1 | | 6 - - | - - 4 | - - - | |----------------------+----------------------+----------------------| | - - - | 7 - - | - - - | | - - - | 5 - - | - - 2 | | 9 - 5 | - 6 8 | 4 - - | *--------------------------------------------------------------------*

Solution so far:
Code: Select all
*--------------------------------------------------------------------* | 125 125 6 | 4 25 7 | 1 5 8 | | 235 23578 9 | 238 2358 1 | 26 267 4 | | 123 12378 4 | 238 9 6 | 12 127 5 | |----------------------+----------------------+----------------------| | 8 15 2 | 9 135 35 | 7 4 6 | | 4 9 3 | 6 7 25 | 8 25 1 | | 6 15 7 | 1238 12358 4 | 23 235 9 | |----------------------+----------------------+----------------------| | 23 6 1 | 7 4 23 | 5 9 8 | | 7 4 8 | 5 13 9 | 136 136 2 | | 9 23 5 | 123 6 8 | 4 13 7 | *--------------------------------------------------------------------*

as already noted, the posted puzzle [24 clues] has more than one answer

Code: Select all: . . 6 | . . . | 9 8 3 . . . | . . 1 | . . . . . 4 | . 9 . | . . . -------+-------+------ . . 2 | . . . | . 4 . . . 3 | 6 7 . | 8 . 1 6 . . | . . 4 | . . . -------+-------+------ . . . | 7 . . | . . . . . . | 5 . . | . . 2 9 . 5 | . 6 8 | 4 . .

however, amirzadeh has somehow solved 25 cells, reaching this 49-cell position [after correcting the error in r1c789] - which does have exactly one answer

Code: Select all: . . 6 | 4 . 7 | 9 8 3 . . 9 | . . 1 | . . 4 . . 4 | . 9 6 | . . 5 -------+-------+------ 8 . 2 | 9 . . | 7 4 6 4 9 3 | 6 7 . | 8 . 1 6 . 7 | . . 4 | . . 9 -------+-------+------ . 6 1 | 7 4 . | 5 9 8 7 4 8 | 5 . 9 | . . 2 9 . 5 | . 6 8 | 4 . 7

amirzadeh, the 1 for r1 must be in c1: not in c2 because the 1 for box4 must be in c2.

by **amirzadeh** » Thu Sep 21, 2006 3:06 pm

Sorry, Sorry I missed an 8 r4c1 and 9 on r7c6.

Code: Select all: *--------------------------------------------------------------------* | - - 6 | - - - | 9 8 3 | | - - - | - - 1 | - - - | | - - 4 | - 9 - | - - - | |----------------------+----------------------+----------------------| | 8 - 2 | - - - | - 4 - | | - - 3 | 6 7 - | 8 - 1 | | 6 - - | - - 4 | - - - | |----------------------+----------------------+----------------------| | - - - | 7 - - | - - - | | - - - | 5 - 9 | - - 2 | | 9 - 5 | - 6 8 | 4 - - | *--------------------------------------------------------------------*

Thanks.

by **ravel** » Thu Sep 21, 2006 5:07 pm

Assume you came here (changed the values in r1c789 in your grid above).

Code: Select all: *--------------------------------------------------------------------* | 125 125 6 | 4 25 7 | 9 8 3 | | 235 23578 9 | 238 2358 1 | 26 267 4 | | 123 12378 4 | 238 9 6 | 12 127 5 | |----------------------+----------------------+----------------------| | 8 15 2 | 9 135 35 | 7 4 6 | | 4 9 3 | 6 7 25 | 8 25 1 | | 6 15 7 | 1238 12358 4 | 23 235 9 | |----------------------+----------------------+----------------------| | 23 6 1 | 7 4 23 | 5 9 8 | | 7 4 8 | 5 13 9 | 136 136 2 | | 9 23 5 | 123 6 8 | 4 13 7 | *--------------------------------------------------------------------*

r1c2 cannot be 1: One way to see it is, that you have a pair 15 in r46c2, another way, that in box 4 the 1 only can be in column 2. In both cases 1 cannot be in the rest of column 2 (r13c2).
r1c2 cannot be 5: In column 1 the only places for a 5 are in box 1. So in this box the 5 must be in column 1 and cannot be in the rest of the box (r12c2).
Therefore r1c2=2.

by **QBasicMac** » Sat Sep 23, 2006 7:42 pm

amirzadeh wrote:I don't understand the references and can't deduct the logic behind some of the answers people have provided. So if you have a solution, some background would be great.

Code: Select all: +---------------+-----------------+---------------+ | 125 125 6 | 4 25 7 | 9 8 3 | | 235 23578 9 | 238 2358 1 | 26 267 4 | | 123 12378 4 | 238 9 6 | 12 127 5 | +---------------+-----------------+---------------+ | 8 15 2 | 9 135 35 | 7 4 6 | | 4 9 3 | 6 7 25 | 8 25 1 | | 6 15 7 | 1238 12358 4 | 23 235 {9} | +---------------+-----------------+---------------+ | 23 6 1 | 7 4 23 | 5 9 8 | | 7 4 8 | 5 13 9 | 136 136 2 | | 9 23 5 | 123 6 8 | 4 13 7 | +---------------+-----------------+---------------+

1)==================
Look at row 1, column 5. It has two candidates, 2 and 5 (r1c5=25).
Well, r2c5=2358.
These are the only two cells in box 2 that contain candidate 5.
Therefore one of these two cells MUST be 5.
That means no other cells in column 5 can contain 5.
So erase candidate 5 from r4c5 and r6c5.

In short, "Locked candidate 5 in box 2"

2)==================
Locked candidate 1 in box 3
Can you see that therefore
- r3c1 changes from 123 to 23
- r3c2 changes from 12378 to 2378

Fix them.

3)==================
Locked candidate 1 in box 4

Yea! Now we can solve cell r1c1, right?

Code: Select all: +---------------+----------------+---------------+ | 125 25 6 | 4 25 7 | 9 8 3 | | 235 23578 9 | 238 2358 1 | 26 267 4 | | 23 2378 4 | 238 9 6 | 12 127 5 | +---------------+----------------+---------------+ | 8 15 2 | 9 13 35 | 7 4 6 | | 4 9 3 | 6 7 25 | 8 25 1 | | 6 15 7 | 1238 1238 4 | 23 235 9 | +---------------+----------------+---------------+ | 23 6 1 | 7 4 23 | 5 9 8 | | 7 4 8 | 5 13 9 | 136 136 2 | | 9 23 5 | 123 6 8 | 4 13 7 | +---------------+----------------+---------------+

4)==================
Locked candidate 5 in box 4

That leads to a solution for cell r1c2. Got it?

Mac

by **Len** » Mon Sep 25, 2006 1:41 am

Or, locked candidate 1 in box 3 means r3c1 changes from 123 to 23 resulting in a single for column 1 (r1c1=1).

by **zzr007** » Mon Oct 02, 2006 12:32 am

*--------------------------------------------------------------------*
| 1 2 6 | 4 5 7 | 9 8 3 |
| 5 8 9 | 3 3 1 | 6 7 4 |
| 3 7 4 | 8 9 6 | 1 2 5 |
|----------------------+----------------------+----------------------|
| 8 1 2 | 9 3 5 | 7 4 6 |
| 4 9 3 | 6 7 2 | 8 5 1 |
| 6 5 7 | 1 8 4 | 2 3 9 |
|----------------------+----------------------+----------------------|
| 2 6 1 | 7 4 3 | 5 9 8 |
| 7 4 8 | 5 1 9 | 3 6 2 |
| 9 3 5 | 2 6 8 | 4 1 7 |
*--------------------------------------------------------------------*

by **QBasicMac** » Mon Oct 02, 2006 12:42 am

[quote="zzr007"]

(a solution)

Hi, zzr007.

Just to let you know that on this forum, posting solutions is a disgrace. Anybody here can easily get a solution, even me, who likes guessing.

The point is the METHODOLOGY used to reach the solution.

Anyway, no problem. You, of course, post whatever you want. Just know that if you post solutions, you thereby earn the disgust and disdain of forum regulars.

Mac

by **udosuk** » Mon Oct 02, 2006 5:01 am

QBasicMac wrote:Hi, zzr007.

Just to let you know that on this forum, posting solutions is a disgrace. Anybody here can easily get a solution, even me, who likes guessing.

The point is the METHODOLOGY used to reach the solution.

Anyway, no problem. You, of course, post whatever you want. Just know that if you post solutions, you thereby earn the disgust and disdain of forum regulars.

Speak for yourself here...

I have no problem whatsoever about people posting solutions (and I am the most frequent "forum regular" here right now), especially for a puzzle posted for 10+ days. And I think only the original posters of the puzzles have a say about that issue, in that case they could politely request them to edit/remove the solutions. Sure, we could make it more subtle by using tiny fonts so only the desired readers would go to the trouble to extract the text, but even in this case I think there is not much damage done here. For serious puzzlers even if they glimpse through the solution they wouldn't remember many digits and it shouldn't affect much if they attempt the actual puzzle later. In fact many puzzle providers provide puzzle solutions either at the same time as the puzzles are published or on the very next day.

IMHO what's not appropriate in this forum is using aggressive/offensive languages to intimidate/scare away newcomers...

I mean, for ???'s sake this person just posted a bunch of numbers... Why treat it like it's a distasteful image of undressed women or a violent bloodshed photo?

Anyway I'm puzzled what gives you the authority to claim that "posting what and what is disgraceful/inappropriate here"... As far as I know only adminstrators and moderators can make that decision... :?:

(I myself wrote something like that in the previous paragraph, but I think it's more common sense and general etiquette...)

by **amirzadeh** » Tue Oct 03, 2006 2:16 pm

Thank you all for your help. I am getting better at seeing the solutions. I don't mind the answers, however any solution site will also give you the same thing so posting a solution is I think a waste of time and typing.

Aram

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