The New Sudoku Players' Forum

[ttt]

As reference…!

Hi All,
For me, I think that ALSs – especially A*ALSs, is one of “Heavy Weapons” that human use to attack hard puzzles . Below puzzle from French’s forum #283 hard (based on link was shown by Denis) that I used A*ALSs to solve.

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*-----------*      #283 hard (on French’s forum)
 |...|12.|.3.|
 |..4|5..|.6.|
 |.2.|..7|...|
 |---+---+---|
 |..8|...|..4|
 |7..|.9.|..5|
 |2..|...|6..|
 |---+---+---|
 |...|4..|.1.|
 |.9.|..6|8..|
 |.6.|.71|...|
 *-----------*
After SSTS (included Coloring : r2c1<>8 & r3c7<>9)
 *--------------------------------------------------------------------*
 | 5689   578    5679   | 1      2      489    | 4579   3      789    |
 | 139    1378   4      | 5      38     389    | 1279   6      12789  |
 | 13589  2      1359   | 3689   46     7      | 145    4589   189    |
 |----------------------+----------------------+----------------------|
 | 13569  135    8      | 2367   16     235    | 12379  279    4      |
 | 7      134    136    | 2368   9      2348   | 123    28     5      |
 | 2      1345   1359   | 378    14     3458   | 6      789    13789  |
 |----------------------+----------------------+----------------------|
 | 358    3578   2357   | 4      358    2389   | 23579  1      6      |
 | 1345   9      12357  | 23     35     6      | 8      2457   237    |
 | 3458   6      235    | 2389   7      1      | 23459  2459   239    |
 *--------------------------------------------------------------------*

01: Present as Diagram:

Code: Select all

AAALS(14579)r13c7  => r1c6<>8
 ||
(1)r3c7-(1)r45c7=(1)r6c9-(1=4)r6c5-(4)r3c5=(4)r1c6
 ||
(79)r1c7-(4)r1c7=(4)r1c6
 ||
(45)r13c7-(45)r3c8=(hp45)r89c8-(27)r8c8
                                ||
                               (4)r8c8-(4)r8c1=(4-8)r9c1=(8-9)r9c=(9)r7c6-(9=hp38)r2c56
                                ||
                               (5)r8c8-(5=3)r8c5-(3=8)r2c5

02: Dual Kraken : => r2c7<>1

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(1)r5c7
 ||
(1-4)r5c2=(4)r6c2-(4=1)r6c5-(1)r6c9=(1)r12c9
 ||
(1)r5c3--(1)r8c3=(1)r8c1-(1)r23c1
       |                  ||
        -----------------(1)r3c3
                          ||
                         (1)r2c2

03: Present as Diagram:

Code: Select all

AALS(23457)r8c458  => r6c9<>1
 ||
(235)r8c458-
 ||         |
 ||          -(4)r8c8=(4-1)r8c1=(1)r8c3-(1)r5c3
 ||         |                            ||
(7)r8c8-----                            (1)r5c7 
 ||                                      ||
 ||                                     (1-4)r5c2=(4)r6c2-(4=1)r6c5   
 ||
(4)r8c8-(4)r8c1=(4-8)r9c1=(8-9)r9c4=(9-6)r3c4=(6)r3c5-(4)r3c5
       |                                               ||
        ----------------------------------------------(4)r3c8 
                                                       ||
                                                      (4-1)r3c7=(1)r45c7

04: Present as Diagram:

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AALS(2379)r89c9  => r1c6<>9, some singles
 ||
(9)r9c9-(9)r9c4=(9)r7c6
 ||
(7)r8c9-(7)r1c9
 ||      ||
 ||     (9)r1c9 
 ||      ||
 ||     (8)r1c9-(8)r3c89
 ||              ||
 ||             (8-6)r3c4=(6-4)r3c5=(4)r1c6 
 ||              ||
 ||             (8)r3c1-(8)r9c1=(8-9)r9c4=(9)r7c6
 ||
(23)r89c9------(2)r2c9=(2)r2c7-(7)r2c7
         |                      ||
          -(3)r6c9=(hp13)r45c7-(7)r4c7
                                ||         
                               (7)r1c7-(4)r1c7=(4)r1c6
                                ||
                               (7)r7c7-(9)r7c7=(9)r7c6

05: Kraken Cell: => r6c3<>1, single r6c2=1

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(1)r2c1-(1)r8c1=(1)r8c3
 ||
(3)r2c1-(hp38=9)r2c56-(9)r7c6=(9-8)r9c4=(8-4)r9c1=(4-1)r8c1=(1)r8c3
 ||
(9)r2c1-(9)r4c1=(9)r6c3

06: (ht358=7)r7c125-(7=hp38)r2c25-(38=9)r2c6-(9)r7c6=(9)r7c7 => r7c7<>35
07: (2=3)r8c4-(hp35=8)r78c5-(8)r9c4=(8-4)r9c1=(4-1)r8c1=(1)r8c3 => r8c3<>2

08: Kraken Cell: => r7c6<>2

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(2)r9c9-(2)r8c89=(2)r8c4
 ||
(3)r9c9-(3)r6c9=(3)r4c7-(hp35=2)r4c26
 ||
(9)r9c9-(9)r7c7=(9)r7c6

09: (3)r56c3=(3)r4c12-(3)r4c7=(3)r9c7 => r9c3<>3
10: (3=5)r8c5-(5)r7c5=(5)r7c123-(5=2)r9c3-(2)r9c4=(2)r8c4 => r8c4<>3, single r8c4=2
11: Dual Kraken : => r4c7<>9

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(9)r7c7
 ||
(7)r7c7-(7=3)r8c9-(3)r6c9=(3)r4c7
 ||
(2)r7c7—(9)r7c7=(9)r7c6-(9=hp38)r2c56-(38=7)r2c2-(7)r2c7
       |                                          ||
        -----------------------------------------(2)r2c7
                                                  ||
                                                 (9)r2c7

12: (7)r46c8=(7)r8c8-(7=3)r8c9-(3)r6c9=(3)r4c7 => r4c7<>7
13: (4)r8c1=(4-5)r8c8=(5)r9c78-(5=2)r9c3-(2)r9c9=(2-1)r2c9=(1)r2c1 => r8c1<>1, single r8c3=1
14: (7)r2c7=(7)r1c7-(7)r1c3=(7-2)r7c3=(2)r7c7 => r2c7<>2, some singles
15: XY-wing: r4c7=32, r7c7=29, r9c9=93 => r9c7 & r6c9<>3, some singles
16: XY-wing: r2c7=79, r1c9=98, r1c2=87 => r2c2 & r1c7<>7, singles to the end

Hope not much typos and a better proof by Experts!

Thanks to all,
ttt

[hobiwan]

02: Dual Kraken : => r2c7<>1

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(1)r5c7
 ||
(1-4)r5c2=(4)r6c2-(4=1)r6c5-(1)r6c9=(1)r12c9
 ||
(1)r5c3--(1)r8c3=(1)r8c1-(1)r23c1
       |                  ||
        -----------------(1)r3c3
                          ||
                         (1)r2c2

This has nothing to do with the topic of the thread, but why is it called a "Kraken" (and not simply a "Forcing Net")?

Besides (found by my solver, not by me):

Code: Select all

r5c3 -1- r456c2 =1= r2c2 -1- r2c7

[champagne]

Hi,

Puzzle "283 hard" prepared by JPF is not an easy one.

I am not using directly ALS, but AHS/AC.
As far as I know, it gives exactly the same solving capability.

Here the diagram of the AICs net suggested by my solver to go ahead.

This is dedicated to players having the flavour that r1c6 could be a start.
This has been found using the option (I could say "strategy") to select moves leading to a new known node.

I have to check, but it seems to me that no ALS/AHS has been used here, so this should be something in the field of Denis'rules.

Code: Select all

5689  578  5679  |1     2   489  |4579  3    789     
1389  1378 4     |5     38  389  |1279  6    12C789   
13589 2    1359  |3689  46  7    |1459  4589 189     
--------------------------------------------------
13569 135  8     |2367  16  235  |12379 279  4       
7     134  136   |2368  9   2348 |123   28   5       
2     1345 1359  |378   14  3458 |6     789  13789
--------------------------------------------------
358   3578 2357  |4     358 2389 |23579 1    6       
1345  9    12357 |23    35  6    |8     2457 237     
3458  6    235   |2389  7   1    |23459 2459 239 

the first net is pretty long

Code: Select all

      ____________________ |9r1c9|                   
      /                     |     |                    |7r7c7|
9r1c6 |- 8r3c1 | = 8r3c89 - |8r1c9| = 7r1c9 - 7r2c17 = |7r4c7| - 5r8c138 = 5r8c5 _ 5r8c8
      |- 8r3c4 |

                          |1r3c7|
                          |4r3c7|
        |5r3c8  - 5r3c7 = |9r3c7| -
        |                          \
5r8c8 = |5r9c8  - 4r9c8 = |4r9c1| -  9r1c6
                          |4r9c7|

The second one is much simpler

Code: Select all

5r9c1 ---------------------\
5r9c3 - 5r9c78 = | 5r7c7 |--\
                 | 5r7c8 |   |
                             |
5r9c7 - 5r3c7 = |1r3c7|      |
                |4r3c7|---------8r1c6
                |7r3c7|     /
                           /
5r9c8 - 4r9c8 = |4r9c1|   /
                |4r9c7|--/

And four nodes are found


2 r1c6=4 3 r3c5=6 4 r4c5=1 5 r5c2=4 6 r6c5=4

[ttt]

02: Dual Kraken : => r2c7<>1

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(1)r5c7
 ||
(1-4)r5c2=(4)r6c2-(4=1)r6c5-(1)r6c9=(1)r12c9
 ||
(1)r5c3--(1)r8c3=(1)r8c1-(1)r23c1
       |                  ||
        -----------------(1)r3c3
                          ||
                         (1)r2c2

... but why is it called a "Kraken" (and not simply a "Forcing Net")?

I'm not named, I follow the name that called by Myth, Ronk, Mike.

Besides (found by my solver, not by me):

Code: Select all

r5c3 -1- r456c2 =1= r2c2 -1- r2c7

For me, the presenting deductions by Krakens or my diagrams show all candidates & cells that relate for eliminating - yours is not...
BTW, other way to eliminate r2c7=1 by Kraken Column with 1's on col.2

Code: Select all

(1)r2c2
 ||
(1)r46c2-(1)r5c23=(1)r5c7
 ||
(1-4)r5c2=(4)r6c2-(4=1)r6c5-(1)r6c9=(1)r23c9

Anyway, thanks for your comments!
ttt

[ronk]

I'm not named, I follow the name [edit: kraken] that called by Myth, Ronk, Mike.

You must have missed my post a couple years back ...

Kraken Fish ... Kraken Blossom and House ... Kraken UR ... Kraken BUG ... Kraken ALS ... Kraken A*LS ... Kraken (insert your favorite restricted subset here) ...

Franken kraken kracken smacken ... totally over the top IMO.

I reluctantly use the "kraken" term because everyone else seems to ... but I certainly don't consider myself a proponent.

[edit 1: added the following]

Besides (found by my solver, not by me):

Code: Select all

r5c3 -1- r456c2 =1= r2c2 -1- r2c7

For me, the presenting deductions by Krakens or my diagrams show all candidates & cells that relate for eliminating - yours is not...

After incorporating hobiwan's suggestion for the 3rd line of your "dual kraken", we have [edit 2: a NL with one multiple-inference or an] AAIC or "single kraken" deduction. In the NL notation of this forum ...

r2c7-1-r12c9=1=r6c9-1-r6c5-4-r6c2=4=r5c2(=1=r5c7-1-)(=1=r5c3-1-r456c2=1=r2c2-1-)r2c7 ==> r2c7<>1
[edit 2: moved both right-hand ')' parentheses]]

BTW, other way to eliminate r2c7=1 by Kraken Column with 1's on col.2

Code: Select all

(1)r2c2
 ||
(1)r46c2-(1)r5c23=(1)r5c7
 ||
(1-4)r5c2=(4)r6c2-(4=1)r6c5-(1)r6c9=(1)r23c9

With only one "kraken house", that is better than two kraken houses.

[champagne]

Hi,

This is dedicated to players having the flavour that r1c6 could be a start.

I had not to wait so long. A highly skilled french girl found the same first steps as my solver.

As often, she had a diferent way to bring the probe, especially for the first step.

champagne

[daj95376]

[Withdrawn: mindless]

[denis_berthier]

For those who don't like nets, here is SudoRules solution, using only chains or whips.

Remember that the dot at the place of a right-linking candidate (rlc) in the last cell of a whip indicates that no rlc compatible with the target and the previous rlc's is possible.

SER = 9,1 NRCZT = 11

***** SudoRules version 13.7w *****
...12..3.
..45...6.
.2...7...
..8.....4
7...9...5
2.....6..
...4...1.
.9...68..
.6..71...
hidden-single-in-a-row ==> r7c9 = 6
interaction row r1 with block b1 for number 6 ==> r3c3 <> 6, r3c1 <> 6
nrc-chain[2] n9{r3c4 r9c4} - n9{r7c6 r7c7} ==> r3c7 <> 9
naked-triplets-in-a-column {n3 n8 n5}{r2 r7 r8}c5 ==> r6c5 <> 8, r6c5 <> 5, r6c5 <> 3, r4c5 <> 5
interaction column c5 with block b8 for number 5 ==> r7c6 <> 5
naked-triplets-in-a-column {n3 n8 n5}{r2 r7 r8}c5 ==> r4c5 <> 3, r3c5 <> 8
nrc-chain[2] n8{r9c1 r9c4} - n8{r7c5 r2c5} ==> r2c1 <> 8
naked-triplets-in-a-column {n3 n8 n5}{r2 r7 r8}c5 ==> r3c5 <> 3
nrczt-whip-cn[5] n1{r2c9 r6c9} - {n1 n4}r6c5 - n4{r5c6 r5c2} - n1{r5c2 r5c3} - {n1r6c2 .} ==> r2c7 <> 1
nrczt-whip-rn[7] {n1 n4}r6c5 - n4{r6c2 r5c2} - n1{r5c2 r5c3} - n1{r8c3 r8c1} - n1{r3c1 r3c7} - n4{r3c7 r3c8} - {n4r8c8 .} ==> r6c9 <> 1
interaction column c9 with block b3 for number 1 ==> r3c7 <> 1
nrc-chain[3] n1{r5c7 r4c7} - {n1 n6}r4c5 - n6{r5c4 r5c3} ==> r5c3 <> 1
nrczt-whip-rn[7] n1{r8c3 r8c1} - n4{r8c1 r9c1} - n8{r9c1 r9c4} - n9{r9c4 r3c4} - n9{r3c3 r1c3} - {n9 n3}r2c1 - {n3r3c3 .} ==> r6c3 <> 1
nrczt-whip-rc[7] n1{r8c3 r3c3} - n1{r3c9 r2c9} - n2{r2c9 r2c7} - n7{r2c7 r2c2} - n7{r1c3 r7c3} - n2{r7c3 r7c6} - {n2r8c4 .} ==> r8c3 <> 3
nrczt-whip-rc[8] n1{r8c3 r3c3} - n1{r2c1 r2c9} - n2{r2c9 r2c7} - n7{r2c7 r2c2} - n7{r7c2 r7c3} - n2{r7c3 r7c6} - {n2 n3}r8c4 - {n3r8c5 .} ==> r8c3 <> 5
nrczt-whip-cn[8] n1{r5c7 r4c7} - {n1 n6}r4c5 - n6{r5c4 r3c4} - n9{r3c4 r9c4} - n9{r9c9 r7c7} - n3{r7c7 r9c7} - {n3 n2}r9c9 - {n2r9c8 .} ==> r5c7 <> 2
nrczt-whip-rc[9] n2{r5c6 r5c8} - n2{r8c8 r8c9} - n2{r8c4 r7c6} - n9{r7c6 r7c7} - n7{r7c7 r8c8} - n7{r4c8 r4c7} - n1{r4c7 r5c7} - n3{r5c7 r9c7} - {n3r9c9 .} ==> r4c4 <> 2
nrczt-whip-rc[9] n1{r6c2 r6c5} - n4{r6c5 r3c5} - n6{r3c5 r3c4} - n9{r3c4 r9c4} - n8{r9c4 r9c1} - n8{r7c2 r1c2} - n7{r1c2 r1c3} - {n7 n9}r1c9 - {n9r1c6 .} ==> r2c2 <> 1
interaction column c2 with block b4 for number 1 ==> r4c1 <> 1
nrczt-whip-rc[8] {n3 n8}r2c5 - {n8 n9}r2c6 - n9{r7c6 r9c4} - n8{r9c4 r7c6} - {n8 n5}r7c1 - {n5 n3}r7c5 - {n3 n7}r7c2 - {n7r2c2 .} ==> r2c1 <> 3
nrczt-whip-rc[9] n9{r7c7 r7c6} - n2{r7c6 r7c3} - n7{r7c3 r7c2} - n7{r8c3 r1c3} - n6{r1c3 r1c1} - n5{r1c1 r1c2} - n8{r1c2 r2c2} - {n8 n3}r2c6 - {n3r2c5 .} ==> r7c7 <> 5
nrct-chain[11] n4{r1c6 r3c5} - n6{r3c5 r3c4} - n9{r3c4 r9c4} - n8{r9c4 r9c1} - n4{r9c1 r8c1} - n4{r8c8 r9c8} - n4{r9c7 r1c7} - {n4 n5}r3c7 - n5{r9c7 r9c3} - n5{r7c1 r7c5} - n8{r7c5 r2c5} ==> r1c6 <> 8
nrczt-whip-rn[9] n1{r4c5 r6c5} - n4{r6c5 r3c5} - n4{r3c8 r1c7} - {n4 n9}r1c6 - n9{r7c6 r7c7} - n7{r7c7 r2c7} - n2{r2c7 r2c9} - n9{r2c9 r2c1} - {n1r2c1 .} ==> r4c7 <> 1
hidden-single-in-a-block ==> r5c7 = 1
nrczt-whip-rn[10] n1{r2c9 r2c1} - n1{r8c1 r8c3} - n7{r8c3 r8c8} - n7{r7c7 r4c7} - n3{r4c7 r6c9} - {n3 n2}r8c9 - {n2 n9}r9c9 - n9{r7c7 r7c6} - n9{r2c6 r2c7} - {n2r2c7 .} ==> r2c9 <> 7
nrczt-whip-rn[7] n9{r7c7 r7c6} - n2{r7c6 r7c3} - n7{r7c3 r7c2} - n7{r2c2 r2c7} - n2{r2c7 r2c9} - n9{r2c9 r2c1} - {n1r2c1 .} ==> r7c7 <> 3
nrczt-whip-bn[5] n2{r5c8 r4c7} - n3{r4c7 r6c9} - n3{r9c9 r9c7} - n5{r9c7 r8c8} - {n4r8c8 .} ==> r9c8 <> 2
nrczt-whip-bn[5] n2{r5c8 r4c7} - n3{r4c7 r6c9} - n3{r9c9 r9c7} - n5{r9c7 r9c8} - {n4r9c8 .} ==> r8c8 <> 2
interaction column c8 with block b6 for number 2 ==> r4c7 <> 2
nrczt-whip-rc[6] n3{r4c7 r6c9} - n7{r6c9 r6c4} - n7{r6c8 r8c8} - {n7 n2}r8c9 - {n2 n9}r9c9 - {n9r7c7 .} ==> r4c7 <> 7
nrczt-whip-bn[6] {n3 n9}r4c7 - n9{r7c7 r7c6} - n9{r9c4 r3c4} - n9{r3c8 r9c8} - n5{r9c8 r8c8} - {n4r8c8 .} ==> r9c7 <> 3
hidden-single-in-a-column ==> r4c7 = 3
nrczt-whip-rc[5] {n2 n3}r8c4 - n3{r8c9 r9c9} - {n3 n5}r9c3 - n5{r9c8 r8c8} - {n5r8c5 .} ==> r9c4 <> 2
nrczt-whip-cn[6] n5{r6c6 r4c6} - {n5 n1}r4c2 - {n1 n6}r4c5 - n6{r3c5 r3c4} - n9{r3c4 r9c4} - {n8r9c4 .} ==> r6c6 <> 8
nrczt-whip-rn[6] {n4 n9}r1c6 - n9{r7c6 r7c7} - n7{r7c7 r2c7} - n2{r2c7 r2c9} - n9{r2c9 r2c1} - {n1r2c1 .} ==> r1c7 <> 4
naked and hidden singles ==> r1c6 = 4, r3c5 = 6, r4c5 = 1, r6c5 = 4, r4c2 = 5, r4c6 = 2, r8c4 = 2, r5c8 = 2, r6c6 = 5, r5c2 = 4, r6c2 = 1
interaction row r5 with block b5 for number 8 ==> r6c4 <> 8
interaction block b4 with column c3 for number 3 ==> r9c3 <> 3, r7c3 <> 3, r3c3 <> 3
nrczt-whip-cn[2] n3{r7c5 r2c5} - {n3r2c2 .} ==> r7c6 <> 3
nrc-chain[3] n9{r3c4 r2c6} - n3{r2c6 r5c6} - n8{r5c6 r5c4} ==> r3c4 <> 8
interaction block b2 with row r2 for number 8 ==> r2c9 <> 8, r2c2 <> 8
nrc-chain[3] {n9 n3}r3c4 - n3{r6c4 r6c3} - n9{r6c3 r4c1} ==> r3c1 <> 9
nrc-chain[3] n3{r3c1 r3c4} - n9{r3c4 r9c4} - n8{r9c4 r9c1} ==> r9c1 <> 3
nrc-chain[3] {n7 n3}r6c4 - n3{r9c4 r9c9} - {n3 n7}r8c9 ==> r6c9 <> 7
interaction block b6 with column c8 for number 7 ==> r8c8 <> 7
nrc-chain[3] n3{r3c1 r3c4} - n9{r3c4 r9c4} - n8{r9c4 r9c1} ==> r3c1 <> 8
interaction row r3 with block b3 for number 8 ==> r1c9 <> 8
nrc-chain[3] {n1 n9}r2c1 - n9{r2c6 r3c4} - n3{r3c4 r3c1} ==> r3c1 <> 1
nrc-chain[3] n1{r3c9 r3c3} - {n1 n9}r2c1 - n9{r2c6 r3c4} ==> r3c9 <> 9
hxy-rn-chain[4] {c8 c1}r8n4 - {c1 c3}r8n1 - {c3 c9}r3n1 - {c9 c8}r3n8 ==> r3c8 <> 4
hidden-single-in-a-block ==> r3c7 = 4
row R7 : hxyzt4-cn-chain-type-1 on cn-cells {r7 r2}c5n8 - {r2 r5}c6n8 - {r5 r2}c6n3 - {r2 r7}c2n3 ==> r7c2 <> 8
hidden-single-in-a-column ==> r1c2 = 8
nrc-chain[4] {n9 n3}r3c4 - n3{r3c1 r2c2} - n7{r2c2 r1c3} - {n7 n9}r1c9 ==> r3c8 <> 9
nrc-chain[4] n8{r7c1 r9c1} - n4{r9c1 r9c8} - {n4 n5}r8c8 - n5{r8c5 r7c5} ==> r7c5 <> 8
hidden-single-in-a-column ==> r2c5 = 8
interaction column c5 with block b8 for number 3 ==> r9c4 <> 3
naked and hidden singles
GRID papyg/Extra283-hard.sdk SOLVED. LEVEL = L11, MOST COMPLEX RULE = NRCT11
687124539
134589762
529367481
958612374
746893125
213745698
372458916
491236857
865971243

[ronk]

This mindless posting of the complete solution paths of programmed solvers is becoming numbingly boring ... and irritating.

[ttt]

Hi All,

Other puzzle from French’s Forum #284 – hard, quite simpler than above puzzle and as practice my NL notation…

Code: Select all

*-----------*
 |..1|...|.23|
 |...|3..|..4|
 |.2.|5..|6..|
 |---+---+---|
 |.5.|.4.|...|
 |...|178|...|
 |...|.5.|.7.|
 |---+---+---|
 |..8|..6|.3.|
 |3..|..7|...|
 |64.|...|1..|
 *-----------*
After SSTS (included 01 X-wing & 01 Coloring: r2c13 & r7c19<>7, r8c7<>5)
 *--------------------------------------------------------------------*
 | 4589   689    1      | 7      689    49     | 589    2      3      |
 | 589    6789   569    | 3      2689   129    | 5789   1589   4      |
 | 4789   2      3      | 5      89     149    | 6      189    1789   |
 |----------------------+----------------------+----------------------|
 | 12789  5      2679   | 269    4      239    | 2389   1689   12689  |
 | 29     369    2469   | 1      7      8      | 23459  4569   2569   |
 | 1289   13689  2469   | 269    5      239    | 23489  7      12689  |
 |----------------------+----------------------+----------------------|
 | 1259   179    8      | 249    129    6      | 24579  3      259    |
 | 3      19     259    | 2489   129    7      | 2489   45689  25689  |
 | 6      4      279    | 289    3      5      | 1      89     2789   |
 *--------------------------------------------------------------------*

01: ALS:([r9c39]=7|2=[r9c39])=2=[r9c4]-AUR(19)r78c25:([r78c5]=2|7=[r7c2])=7[r7c7]=7=[r9c9] => r9c9<>89
(hp27)r9c39=(2)r9c4-(2)r78c5=AUR(19)r78c25=(7)r7c2-(7)r7c7=(7)r9c9

02: [r1c7]=5=[r1c1]-4=[r3c1]-7=[r2c2]=AUR(19)r78c25:([r7c2]=7|2=[r78c5])=2=[r2c5]=2=[r2c6]-1=[r2c8]-5-[r2c8] => r2c8<>5, some singles
(5)r1c7=(5-4)r1c1=(4-7)r3c1=(7)r2c2-(7)r7c2=AUR(19)r78c25=(2)r78c5-(2)r2c5=(2-1)r2c6=(1)r2c8

03: [r3c1]-8-[r3c5]-9-[r1c6]-4=[r1c1]=4=[r3c1]-8-[r3c1] => r3c1<>8
(8=9)r3c5-(9=4)r1c6-(4)r1c1=(4)r3c1

04: [r3c9]-8-[r3c5]-9-[r1c6]-4=[r1c1]=4=[r3c1]-7=[r3c9]-8-[r3c9] => r3c9<>8, singles to the end
(8=9)r3c5-(9=4)r1c6-(4)r1c1=(4-7)r3c1=(7)r3c9

I'm sorry if something's wrong and please correct me for NL notation…!

Thanks to All,
ttt

[champagne]

Hi ttt,
I had a look with the same strategy as for 283H.

We have a slightly different start.
1)Small remark, couloring on "7" is a SwordFish
2)You can clear '9' r3c1 using a UR pattern
3)My solver entered the search for a new fix before clearing 5r8c7

so the start was

Code: Select all

*--------------------------------------------------------------------*
 | 4589   689    1      | 7      689    49     | 589    2      3      |
 | 589    6789   569    | 3      2689   129    | 5789   1589   4      |
 | 478    2      3      | 5      89     149    | 6      189    1789   |
 |----------------------+----------------------+----------------------|
 | 12789  5      2679   | 269    4      239    | 2389   1689   12689  |
 | 29     369    2469   | 1      7      8      | 23459  4569   2569   |
 | 1289   13689  2469   | 269    5      239    | 23489  7      12689  |
 |----------------------+----------------------+----------------------|
 | 1259   179    8      | 249    129    6      | 24579  3      259    |
 | 3      19     259    | 2489   129    7      | 24589  45689  25689  |
 | 6      4      279    | 289    3      5      | 1      89     2789   |
 *--------------------------------------------------------------------*

The proposal of the solver is to my opinion not as good as yours.
Subject to deeper cheking, again without use of ALS.

The sequence at the beginning is the following
#2r7c4 #9r7c4 giving r7c4=4
#9r9c3 #9r9c4 #9r9c9 giving r9c8=9

Compared to 283H, AICs nets are small.


The second cycle clears 9r4c1; 9r4c3; 9r4c6; 9r4c7


and then nothing special to the end except a XYZ Wing

champagne

[ttt]

Hi champagne,
Thank you very much for your comments.
For French’s forum 284 hard, my keys based on AUR (19)r78c25.

I’m studying your “Full Tagging”, but it seems difficult for me about the concept and… English (of course – I had to use Dictionaries many… many times). I’ll try and if I have any questions about that I’ll ask you…

Thanks again,
ttt

[champagne]

my keys based on AUR (19)r78c25.

My solver does not at all use deadly patterns; only basic UR's. I am thinking for long of introducing in such a case the direct condition (7r7c2 or 2r78c5 ) (one or both) but this has been posponed several times.

I’m studying your “Full Tagging”, but it seems difficult for me about the concept and… English (of course – I had to use Dictionaries many… many times). I’ll try and if I have any questions about that I’ll ask you…

For players already skill in AICs handlng, it should be relatively easy. Full tagging in that case is just one method to hep finding AIC's.

My website has a tutoring, but it is in French!!!

I will be glad to help you if necessary.

champagne

[denis_berthier]

This mindless posting of the complete solution paths of programmed solvers is becoming numbingly boring ... and irritating.

As I wasn't watching this thread, I had missed that one.

A partial solution is of little use for those who want to check the mainsteps without having to re-do all the intermediate resolution work.

Almost all the solutions proposed in this thread were produced by programmed solvers. Much mind work has been put in these solvers.
I'm therefore wondering, Ronk: who are you to make such snide remarks about mindless-ness, with the tone of a landowner finding campers having planted their tent in his field?
You're one of the oldest posters in this and other Sudoku forums, you've been reading and commenting everything; and you've mostly been criticising everything I've done, even though you only understantood part of it, as shown by your recent posts in my T&E thread.

My question is, have you ever invented anything? If so, please give references.

[ronk]

My question is, have you ever invented anything? If so, please give references.

With credit to John Hart Studios ...



Seriously, I'll let my record speak for itself. BTW I don't answer questions about my salary either.