## Stuck again - need next step

Advanced methods and approaches for solving Sudoku puzzles

### Stuck again - need next step

Another V.Hard - maybe I'm biting off more than I can chew here....

Can someone help me just enough to get me moving again please? Not after the full solution. Thanks.

Code: Select all
`GRID:1 . . | . 2 . | . . 36 . 3 | . . 4 | . . .9 . . | 7 1 3 | 8 . 6------+-------+------. . . | 1 . . | 3 7 .5 1 . | . 3 . | . 6 2. 3 . | . . . | . . .------+-------+------. . 8 | . 5 1 | . . 9. . . | 9 . . | . . 14 9 1 | . 6 . | . . .CANDIDATES:[1]   [4578] [457]   | [568] [2]    [5689] | [4579]  [459]   [3]   [6]   [2578] [3]     | [58]  [89]   [4]    | [12579] [1259]  [57]  [9]   [245]  [245]   | [7]   [1]    [3]    | [8]     [245]   [6]   ---------------------+---------------------+-----------------------[28]  [246]  [2469]  | [1]   [489]  [256]  | [3]     [7]     [458] [5]   [1]    [479]   | [48]  [3]    [789]  | [49]    [6]     [2]   [278] [3]    [24679] | [256] [4789] [256]  | [1459]  [14589] [458] ---------------------+---------------------+-----------------------[237] [267]  [8]     | [234] [5]    [1]    | [2467]  [234]   [9]   [237] [2567] [2567]  | [9]   [478]  [278]  | [2467]  [2348]  [1]   [4]   [9]    [1]     | [238] [6]    [278]  | [257]   [2358]  [578] `
Shazbot

Posts: 220
Joined: 24 September 2005

There is another locked candidates situation.

Where can the 4's go in column 9? This should allow some eliminations and a placement in box 6.
SteveF

Posts: 86
Joined: 26 March 2005

### Re: Stuck again - need next step

shazbot wrote:maybe I'm biting off more than I can chew here....

Heh - happens to me a lot.

Since the only occurrences of 4 in column 9 are in box 6, there can be no other 4's there. Eliminating 4 from those gives r5c7=9.

Unfortunately, it looks like that is the end of the easy stuff! My guess is that we are looking for hidden triples or even more advanced techniques.

Mac
QBasicMac

Posts: 441
Joined: 13 July 2005

### Re: Stuck again - need next step

edit: Deleted, because it was just plain wrong!

S
Last edited by simes on Sat Oct 22, 2005 6:08 pm, edited 1 time in total.
simes

Posts: 324
Joined: 11 March 2005
Location: UK

### Re: Stuck again - need next step

simes wrote:One hidden single, then just naked singles.

Mind pointing out exactly where the "hidden single" you refer to is?

Thanks

Mac

Solution So Far
Code: Select all
`1-- -2- --36-3 --4 ---9-- 713 8-6--- 1-- 37-51- -3- 962-3- --- -----8 -51 --9--- 9-- --1491 -6- ---`

Pencilmarks So Far
Code: Select all
`-         4578      457       568       -         5689      457       459       -        -         2578      -         58        89        -         1257      1259      57       -         245       245       -         -         -         -         245       -        28        246       2469      -         489       25689     -         -         458      -         -         47        48        -         78        -         -         -        278       -         24679     24568     4789      256789    15        158       458      237       267       -         234       -         -         2467      234       -        237       2567      2567      -         478       278       2467      2348      -        -         -         -         238       -         278       257       2358      578      `
QBasicMac

Posts: 441
Joined: 13 July 2005

Hi QBasicMac,

Here are 2 quick hints from Simple Sudoku:

1) The 8's in row 5 are locked in box 5.
2) Check out column 6: I think you'll spot something there.

You are pretty close to the avalanche of singles.
Nick67

Posts: 113
Joined: 24 August 2007

### Re: Stuck again - need next step

QBasicMac wrote:
simes wrote:One hidden single, then just naked singles.

Mind pointing out exactly where the "hidden single" you refer to is?

errr... it looks like I answered using the wrong grid... again.

My Apologies.

S
simes

Posts: 324
Joined: 11 March 2005
Location: UK

thanks gang - sometimes I feel I just look at these things too long.

Do I now get the "can't see it unless it hits me in the face" award?
Shazbot

Posts: 220
Joined: 24 September 2005

shazbot wrote:Do I now get the "can't see it unless it hits me in the face" award?

No way! I OWN that award!

simes wrote:it looks like I answered using the wrong grid

Whew! I'm just glad you didn't find one, proving I am blind.

Nick67 wrote:Check out column 6: I think you'll spot something there

I finally found what you were talking about. I would have preferred
this:

"r1c6, r4c6 and r6c6 contain the only occurrences of 5, 6 and 9. Therefore the other candidates in those cells can be erased"

But I have gone through all that before and admit it was my fault not to request exact, specific answers. I hate hints. When I reach the point I am stuck, I want the answer. I get no joy whatsoever out of struggling after I once give up.

That aside, I wish you a lot of grass! I can sleep now.

Mac
QBasicMac

Posts: 441
Joined: 13 July 2005

[1,8,7,6,2,9,4,5,3]
[6,2,3,5,8,4,1,9,7]
[9,4,5,7,1,3,8,2,6]
[8,6,2,1,9,5,3,7,4]
[5,1,4,8,3,7,9,6,2]
[7,3,9,2,4,6,5,1,8]
[2,7,8,4,5,1,6,3,9]
[3,5,6,9,7,8,2,4,1]
[4,9,1,3,6,2,7,8,5]

Posts: 3
Joined: 23 October 2005

For your information, you are just wasting forum space by merely entering solutions. Any programmer can write a quickie program to solve SuDoku puzzles and there are some nice ones already coded and posted on the internet. Even if you solve it yourself with no computer, so what?

The forum is to discuss HOW a given puzzle can be solved, using techniques other than guessing or automatic computer solutions. The solution itself is boring and non-instructive. Nobody here has ever requested a solution.

Mac
QBasicMac

Posts: 441
Joined: 13 July 2005

Hear Hear QB. - Robertsetiadi - could you tell us HOW you did it please - your techniques for dealing with locked cells - disjoint subsets etc? It'd be most helpful in future.

BTW - Nobody on the forum is the least bit interested in postings of completed grids - unless they are a valid part of a discussion concerning technique - Anybody can paste a copy of a grid from one of the multitude of solvers - so please - no more.

stuartn
stuartn

Posts: 211
Joined: 18 June 2005