The New Sudoku Players' Forum

by **udosuk** » Tue Feb 13, 2007 4:43 pm

ravel wrote:To be more precise, the "Strong link of 1s in r5c78 => UR-type 4" doesn't exist here.

Thanks ravel... It's my turn to be blind...

by **Carcul** » Tue Feb 13, 2007 5:34 pm

Ravel wrote:If you remove the 2 in r9c1 instead, you get a harder one:

Code: Select all: *------------------------------------------------------------* | 3678 5 4 | 389 2 79 | 1378 13789 3689 | | 3678 2 9 | 348 47 1 | 378 5 368 | | 378 378 1 | 389 5 6 | 4 23789 2389 | |-------------------+-------------------+--------------------| | 1 37 5 | 49 47 8 | 237 6 239 | | 4 678 267 | 5 3 279 | 178 1789 89 | | 2378 9 237 | 16 16 27 | 5 378 4 | |-------------------+-------------------+--------------------| | 59 346 236 | 126 169 45 | 368 38 7 | | 59 346 8 | 7 69 45 | 236 23 1 | | 27 1 267 | 26 8 3 | 9 4 5 | *------------------------------------------------------------*

1. [r3c2]=8=[r5c2]-8-[r6c1]=8=[r6c8]-8-[r7c8]-3-[r7c3]=3=[r6c3](-3-
-[r6c1])-3-[r4c2]-7-[r4c2], => r4c2<>7, r6c1<>3.

2. [r4c5]-7-[r4c2]-3-[r6c3]-2-[r6c6]-7-[r4c5], => r4c5<>7.

Carcul

by **999_Springs** » Fri Mar 02, 2007 8:53 pm

Is it possible to remove both the 2 in r9c1 and the 1 in r4c1 and still get a puzzle with a unique solution?

(I was going to post this much earlier but due to "circumstances beyond my control" I was unable to access this site then.)

by **ravel** » Fri Mar 02, 2007 9:47 pm

No, there are 3 minimal puzzles, without 9 in r1c6 and 2 in r9c1, without 9 in r1c6 and 9 in r9c7 and without 1 in r4c1.

I calculate them using gsf's program, where i have a batch file (i called it gsfmin.bat) with this text, entered in notepad:
sudoku -m puzzles.txt > min.txt
When i copy the puzzle(s) to puzzles.txt (in the directory of gsf's program and the batch file), i only need to doubleclick the batch file in the explorer to get the minimals in min.txt.

by **ArkieTech** » Fri Mar 02, 2007 10:13 pm

post deleted

by **ravel** » Sat Mar 03, 2007 12:06 am

ArkieTech wrote:Single [R7C2]= 6

Cant see that, please explain.

by **daj95376** » Sat Mar 03, 2007 1:12 am

These eliminations are not supported by the contents of the grid when they occur.

Code: Select all: ColBox [R7C2]<> 6 ColBox [R8C2]<> 6 *--------------------------------------------------------------------* | 3678 5 4 | 389 2 79 | 1378 13789 3689 | | 3678 2 9 | 348 478 1 | 378 5 368 | | 378 378 1 | 389 5 6 | 4 23789 2389 | |----------------------+----------------------+----------------------| | 1 37 5 | 249 479 8 | 237 6 239 | | 4 *678 *267 | 5 3 279 | 1278 12789 289 | | 2378 9 237 | 126 167 27 | 5 2378 4 | |----------------------+----------------------+----------------------| | 2359 34-6 *236 | 1269 169 2459 | 2368 238 7 | | 2359 34-6 8 | 7 69 2459 | 236 23 1 | | 27 1 *267 | 268 68 3 | 9 4 5 | *--------------------------------------------------------------------*

by **ArkieTech** » Sat Mar 03, 2007 4:14 am

ravel said:

Cant see that, please explain.

daj95376 said:

These eliminations are not supported by the contents of the grid when they occur.

OOPs

My boo boo I will delete my post.

Sorry about the confusion.

Hope this is right

Code: Select all: *-----------* |.5.|.2.|...| |.29|..1|.5.| |...|..6|4..| |---+---+---| |1.5|..8|.6.| |4..|53.|...| |.9.|...|..4| |---+---+---| |...|...|..7| |..8|7..|..1| |.1.|..3|9..| *-----------* *--------------------------------------------------------------------------* | 3678 5 13467 | 3489 2 479 | 13678 13789 3689 | | 3678 2 9 | 348 478 1 | 3678 5 368 | | 378 378 137 | 389 5789 6 | 4 123789 2389 | |------------------------+------------------------+------------------------| | 1 37 5 | 249 479 8 | 237 6 239 | | 4 678 267 | 5 3 279 | 1278 12789 289 | | 23678 9 2367 | 126 167 27 | 123578 12378 4 | |------------------------+------------------------+------------------------| | 23569 346 2346 | 124689 145689 2459 | 23568 2348 7 | | 23569 346 8 | 7 4569 2459 | 2356 234 1 | | 2567 1 2467 | 2468 4568 3 | 9 248 2568 | *--------------------------------------------------------------------------* Hidden Single [R3C5]=5 Row Hidden Single [R6C7]=5 Row Hidden Single [R9C9]=5 Col Hidden Single [R1C3]=4 Box Hidden Single [R3C3]=1 Col BoxCol [R9C1]<> 6 BoxRow [R6C8]<> 1 BoxRow [R6C3]<> 6 BoxCol [R7C1]<> 6 BoxCol [R2C7]<> 6 ColBox [R7C4]<> 4 ColBox [R9C4]<> 4 ColBox [R7C5]<> 4 ColBox [R8C5]<> 4 ColBox [R9C5]<> 4 Hidden Single [R9C8]=4 Row BoxCol [R7C4]<> 6 BoxCol [R2C5]<> 8 Then it takes trips *--------------------------------------------------------------------* | 3678 5 4 | 389 2 79 | 1378 13789 3689 | | 3678 2 9 | 348 478 1 | 378 5 368 | | 378 378 1 | 389 5 6 | 4 23789 2389 | |----------------------+----------------------+----------------------| | 1 37 5 | 249 479 8 | 237 6 239 | | 4 678 267 | 5 3 279 | 1278 12789 289 | | 2378 9 237 | 126 167 27 | 5 2378 4 | |----------------------+----------------------+----------------------| | 2359 346 236 | 1269 169 2459 | 2368 238 7 | | 2359 346 8 | 7 69 2459 | 236 23 1 | | 27 1 267 | 268 68 3 | 9 4 5 | *--------------------------------------------------------------------*

by **Eioru** » Sat Mar 03, 2007 12:28 pm

I want to know what this puzzle rating in ER and its content. Thanks.

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

by **ronk** » Sat Mar 03, 2007 1:13 pm

Eioru wrote:I want to know what this puzzle rating in ER and its content. Thanks.

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