## Help sought! Times Sudoku Puzzle no 472

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### Help sought! Times Sudoku Puzzle no 472

I have been doing Su Doku for a while and whilst not the fastest kid on the block I can usually solve them. However last Thursdays Times Fiendish Su Doku has got me beat. Can anyone give me the next step? I have checked with the solution and so far I have not made any mistakes.

The puzzle was:

***87***5
13****487
*****5***
*5****174
*********
893****2*
***7*****
614****98
5***98***

I have got to here:

**287***5
135***487
**8**5***
256*8*174
**1***839
893**7526
3897***5*
614***798
527*98*4*

I am sure there must be some technique I don't know about!
Any help will be greatly appreciated.
UKGuy

Posts: 2
Joined: 22 November 2005

[Edited by Pappocom]

thanks
Guest

Posts: 312
Joined: 25 November 2005

### Re: Help sought! Times Sudoku Puzzle no 472

UKGuy wrote:Can anyone give me the next step?

Angus Johnson's Simple Sudoku program has a pleasant graphic interface and can provide hints on a step-by-step basis as you need them.

However, if you want a specific hint from someone in a forum such as this, you really need to provide the candidate list at your sticking point. For the puzzle you asked about, if your candidate list were ...
Code: Select all
` *-----------------------------------------------------------------------------* | 49      46      2       | 8       7       13469   | 369     16      5       | | 1       3       5       | 269     26      269     | 4       8       7       | | 479     467     8       | 123469  12346   5       | 2369    16      123     | |-------------------------+-------------------------+-------------------------| | 2       5       6       | 39      8       39      | 1       7       4       | | 47      47      1       | 2456    2456    246     | 8       3       9       | | 8       9       3       | 14      14      7       | 5       2       6       | |-------------------------+-------------------------+-------------------------| | 3       8       9       | 7       1246    1246    | 26      5       12      | | 6       1       4       | 235     235     23      | 7       9       8       | | 5       2       7       | 136     9       8       | 36      4       13      | *-----------------------------------------------------------------------------*`

... they might point to the naked pair 16 in box 3,
or naked pair 14 in box 5,
or the lock by box 3 on candidate 2 in row 3,
or the lock by box 9 on candidate 2 in row 7,
etc. etc.
Last edited by ronk on Wed Nov 23, 2005 8:51 am, edited 1 time in total.
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

### Thanks!

Thanks Ronk the program you sent me to showed me immediately where the gap in my logic was!
UKGuy

Posts: 2
Joined: 22 November 2005

I programmed that one in just now and my site worked it out. Also gives the steps it uses, and does it online, so no downloads.

Yours is the latest one entered so will come up automatically

http://sudoku.sampercy.com/index.php

I know you've solved it now, but can you tell me if this is helpful? I'm still working on it when I can.

Sam.
SammyJ

Posts: 4
Joined: 17 November 2005

I don't really understand the annotation on that site, could somebody give direction from here, my program is under construction and so i am doing it manualy

|49 :46 : 2 | 8 : 7 134|3 9:1 6: 5 |
| 1 : 3 : 5 |269:26:269| 4 : 8 : 7 |
|479:467: 8 |134:134: 5 |239: 16: 23|
| 2 : 5 : 6 | 39: 8 : 39| 1 : 7 : 4 |
| 47: 47: 1 |256:256: 26| 8 : 3 : 9 |
| 8 : 9 : 3 |
14: 14: 7 | 5 : 2 : 6 |
| 3 | 8 | 9 | 7 :
146:146| 26: 5 : 12|
| 6 : 1 : 4 |235:235: 23| 7 : 9 : 8 |
| 5 : 2 : 7 |
16 : 9 : 8 | 36: 4 13|
Pi

Posts: 389
Joined: 27 May 2005

Pi wrote:I don't really understand the annotation on that site

The parenthesized locations are (x, y) => (col, row) which is reversed from the more usual row-col notation such as r4c3. Also ...
groups 1 to 9 are rows 1 to 9,
groups 10 to 18 are columns 1 to 9, and
groups 19 to 27 are boxes 1 to 9.

I have no idea why the user is asked to perform such mental gymnastics.

could somebody give direction from here

Look for a naked quad in column 6
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

Simple Sudoku looks good. An alternative Sudoku grid with visual hints is http://www.axcis.com.au/numbler.
masb

Posts: 16
Joined: 17 November 2005

### Solution for Puzzle 472

I have the solution for this puzzle, can you give me your email so i can send it to you.
foxface

Posts: 4
Joined: 08 December 2005

### Help sought! Times Sudoku Puzzle No.472

ronk wrote:" ...I have no idea why the user is asked to perform such mental gymnastics..."

I share your same opinion Ronk. Whilst commending anyone for expanding their programming skills, I too find SammyJ's notation of using 'x' (for column) and 'y' (for row) is less "user-friendly" than this forum's established practice of defining a cell, say r8c4, where the "r" obviously refers to the row number and "c" the column number.

Similarly, dividing the grid into nine 3X3 boxes (numbered 1 to 9) is far preferable to Sammyj's notation of defining these boxes as groups 19 to 27 - for example, 'box 7' is mentally much easier to focus in your mind compared to locating where 'group 25' is.

Cec
Cec

Posts: 1039
Joined: 16 June 2005

cecbevwr and ronk:

It makes sense to define it this way, with each group as a collection of cells, because it's then easy to add additional groups, like diagonals, and the whole idea can then be extended further to multiple grids.
Lardarse

Posts: 106
Joined: 01 July 2005

Lardarse wrote:with each group as a collection of cells, because it's then easy to add additional groups, like diagonals, and the whole idea can then be extended further to multiple grids.

Most people think in terms of rows, columns, and boxes. Should users pay a penalty to make it easier for the programmer? Or make extension easier to puzzle styles that very people care about? IMO the answers are clearly ... "no" and "no".
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

I have completed every puzzle since 472 apart from yesterday's Fiendish 512 but looking at this forum I see 472 is a classic.

I reached the grid submitted by Ronk and got a little further tidying up box 2 but have not completed another cell yet. I use a Mac so the applications mentioned are no use to me. Can someone point me to the next step, I'm not so much interested in the final solution, I have a program which will display that, but I wonder if there is a logical technique I am not using.

Many thanks.
David B

Posts: 15
Joined: 16 June 2005

If you have got to the stage where i posted..

In collum 6 there is a hidden pair of 1 and 4

Therefore you can eliminate some more candidates.
Pi

Posts: 389
Joined: 27 May 2005