Problem with the killer sudoku of june 9

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Ron@ldK
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Problem with the killer sudoku of june 9

Post by Ron@ldK »

Good afternoon,

I am a fan of the sum- or killersudoku's so I downloaded the killers from june. I have a problem with the killer from june 9.

The SumoCue-program gives me a solution wich I don't underderstand. The program gives me the following step 'Naked single 1 found in r3 c6.

Unfortunately I am not succeeding in posting the grid here.

Here is the ps-code of the grid:
3x3::k:4096:4096:3842:3842:4356:5381:5381:4359:4359:4096:3850:3850:3842:4356:5381:2831:2831:4359:2322:3850:5140:5140:4356:2327:2327:2831:3866:2322:2322:5140:4382:4382:3104:2327:3866:3866:2852:2852:2852:4382:3104:4137:3114:3114:3114:5165:5165:4143:3104:4137:4137:3891:3636:3636:5165:3383:4143:4143:2874:3891:3891:4157:3636:3903:3383:3383:5186:2874:5188:4157:4157:3143:3903:3903:5186:5186:2874:5188:5188:3143:3143:

Who helps me.

Thnx,
Ronald[/code]
Ruud
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Joined: Fri Dec 30, 2005 10:21 pm

Post by Ruud »

Hi Ronald,

welcome to the forum. Glad you like the killers posted on my website.

to post a candidate grid on the forum, press Control+M in SumoCue and paste it into your message. Put the [code] tags around it to make it more readable.

This is the state of the puzzle in which the progam suggests a naked single in r3c6. To arrive at this stage, you need to work through a series of steps with triple outies for rows 1 and 2 and some advanced reduction of candidates in the upper region of the puzzle.

Code: Select all

.-----------------------.-----------------------.-----------.-----------------------.-----------------------.
|(16)                   |(15)                   |(17)       |(21)                   |(17)                   |
| 123456789   123456789 | 123456789   123456789 | 123456789 | 456789      56789     | 123456789   123456789 |
|           .-----------'-----------.           |           |           .-----------'-----------.           |
|           |(15)                   |           |           |           |(11)                   |           |
| 123456789 | 123456789   123456    | 123456789 | 123456789 | 456789    | 124         1234      | 123456789 |
:-----------:           .-----------'-----------:           :-----------'-----------.           :-----------:
|(9)        |           |(20)                   |           |(9)                    |           |(15)       |
| 123456    | 56789     | 3456789     3456789   | 56789     | 1           35        | 5678      | 123456789 |
|           '-----------:           .-----------'-----------+-----------.           :-----------'           |
|                       |           |(17)                   |(12)       |           |                       |
| 123456      123456    | 3456789   | 123456789   123456789 | 123456789 | 35        | 123456789   123456789 |
:-----------------------'-----------:           .-----------+-----------+-----------'-----------------------:
|(11)                               |           |           |(16)       |(12)                               |
| 12345678    12345678    123456    | 123456789 | 123456789 | 123456789 | 124         123456789   123456789 |
:-----------------------.-----------+-----------+-----------'           :-----------.-----------------------:
|(20)                   |(16)       |           |                       |(15)       |(14)                   |
| 3456789     3456789   | 123456789 | 123456789 | 123456789   123456789 | 356789    | 123456789   123456789 |
|           .-----------:           '-----------+-----------.-----------'           :-----------.           |
|           |(13)       |                       |(11)       |                       |(16)       |           |
| 3456789   | 123456789 | 123456789   123456789 | 12345678  | 123456789   356789    | 356789    | 123456789 |
:-----------:           '-----------.-----------:           :-----------.-----------'           :-----------:
|(15)       |                       |(20)       |           |(20)       |                       |(12)       |
| 123456789 | 123456789   123456    | 3456789   | 12345678  | 3456789   | 124         356789    | 123456789 |
|           '-----------.-----------'           |           |           '-----------.-----------'           |
|                       |                       |           |                       |                       |
| 123456789   123456789 | 3456789     3456789   | 12345678  | 3456789     356789    | 123456789   123456789 |
'-----------------------'-----------------------'-----------'-----------------------'-----------------------'
As you can see, there is only one candidate left in r3c6. This is caused by the pair in the remaining 2 cells of the cage. If you are having trouble with sudoku terminology like "naked single", you should do a bit of reading in my solving guide. As you probably know, the solving strategies for regular sudoku can also be used in killers. My Assassins are handmade and I often manage to slip a in few advanced solving tricks.

Enjoy the rest of the series. July's killers are a little easier, but the August puzzle is back to its usual deadly level.

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
Ron@ldK
New kid on the Grid
New kid on the Grid
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Joined: Fri Aug 04, 2006 10:21 am
Location: Holland

Post by Ron@ldK »

Hi Ruud,

Thnx for answering my question. Unfortunately I still don't get it.

When looking at the 7 steps before getting to the given solution of digit 1 in r3c6.

Step 1: 45 test eliminates in 3 outies of rows 1,2
It leaves 9 for the 3 outies, that implies three combinations for
the 9, 1,2,6 / 1,3,5 and 2,3,4

Step 2: Unplaceable candidate in cage 11(3) in nonet 3
In my opinion only the 9 is not placeable.

Step 3: 45 test eliminates in 3 outies of rows 1,2
I don't see the difference with step 1

Step 4: 45 test eliminates in 3 outies of rows 8,9
It leaves 9 for the 3 outies, that implies three combinations for
the 9, 1,2,6 / 1,3,5 and 2,3,4

Step 5: Unplaceable candidates in cage 16(3) in nonet 9
I don't see any candidates

Step 6: Naked subset of size 3 found in column 7
What is the meaning of this

Step 7: Unplaceable candidates in cage 9(3) in nonet 2,3,6
The combination for 9 can be 1,2,6 / 1,3,5 or 2,3,4 , so 7,8,9 are
not placeable.

Step 8: Digit 1 is placed in r3c6

Can you please explain some of the steps to me.

Tnx again,
Ronald
Ruud
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Posts: 601
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Post by Ruud »

Ron@ldK wrote:Step 1: 45 test eliminates in 3 outies of rows 1,2
It leaves 9 for the 3 outies, that implies three combinations for
the 9, 1,2,6 / 1,3,5 and 2,3,4
The 3 outies add up to (16+15+17+21+17+15+11-90) = 22. Since it cannot go below {589}, all candidates 1,2,3 & 4 are scrapped.
Step 2: Unplaceable candidate in cage 11(3) in nonet 3
In my opinion only the 9 is not placeable.
This is the result of your incorrect calculation in step 1. Because the outie must be 5 or higher, the other 2 digits must add up to 6 or less, but {15} is impossible because it would result in a repeating 5.
Step 3: 45 test eliminates in 3 outies of rows 1,2
I don't see the difference with step 1
Read carefully: it reads "columns" and not "rows"
The outies add up to 9 (maybe you tested the columns in step 1?). The highest possible number is 6 in {126}
Step 4: 45 test eliminates in 3 outies of rows 8,9
It leaves 9 for the 3 outies, that implies three combinations for
the 9, 1,2,6 / 1,3,5 and 2,3,4
Again: Columns, not rows. The surplus is 7 for the 3 outies. {124} is the only configuration for that.
Step 5: Unplaceable candidates in cage 16(3) in nonet 9
I don't see any candidates
I like this one. Hard to find indeed. The outie cell has {124} after the preious step. If you press X (show configurations) you will see that there are no configurations that contain 2 of these digits, which means that the other 2 cells cannot place them.
Step 6: Naked subset of size 3 found in column 7
What is the meaning of this
Step 4 caused 3 cells in column 7 with candidates {124}. These 3 cells will be the ONLY spots in column 7 that can contain 1, 2 or 4. All other cells in column 7 can be cleared of these digits. For more details, read my online solving guide.
Step 7: Unplaceable candidates in cage 9(3) in nonet 2,3,6
The combination for 9 can be 1,2,6 / 1,3,5 or 2,3,4 , so 7,8,9 are
not placeable.
This is because you did not take the previous step into account. The 2 cells in column 7 no longer have digits 1,2 & 4 as candidate. As a result, the combination {126} no is longer valid. This eliminates 6. Now the 2 cells in column 7 only allow {3,5}, so the other cell can only be 1.
Step 8: Digit 1 is placed in r3c6
Perfectly logical.


Difficult killers like these must be handled with care. Read the hints carefully, do not confuse rows & columns, and check your calculations.

Ruud
Ron@ldK
New kid on the Grid
New kid on the Grid
Posts: 3
Joined: Fri Aug 04, 2006 10:21 am
Location: Holland

Post by Ron@ldK »

Thanks a lot,

It's now perfectly clear to me.

I wasn't careful enough and it was all due to my miscalculation.

Ronald
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