The New Sudoku Players' Forum

[P.O.]

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. . .   . 9 .   . . .
. 2 .   5 . .   3 . .
. . .   . . .   . 5 .
. 5 .   . . 7   2 . 8
4 . .   . 2 .   . 1 .
. . .   3 . .   . . 6
. 7 .   2 . .   . . 1
. . 4   . 1 .   . 9 .
. . .   6 . 9   8 . .

....9.....2.5..3.........5..5...72.84...2..1....3....6.7.2....1..4.1..9....6.98..

135678  13468   135678  1478    9       123468  1467    24678   247             
16789   2       16789   5       4678    1468    3       4678    479             
136789  134689  136789  1478    34678   123468  14679   5       2479             
1369    5       1369    149     46      7       2       34      8               
4       3689    36789   89      2       568     579     1       3579             
12789   189     12789   3       458     1458    4579    47      6               
35689   7       35689   2       3458    3458    456     346     1               
23568   368     4       78      1       358     567     9       2357             
1235    13      1235    6       3457    9       8       2347    23457     


[yzfwsf]

step1:Cell Forcing Chain: Each candidate in r7c8 true in turn will all lead to: r13c7<>4
3r7c8 - (3=4)r4c8 - 4r4c4 = 4r13c4 - 4r2c56 = 4r2c89
4r7c8 - 4r46c8 = 4r6c7
6r7c8 - (6=5794)r5678c7
step2:Dynamic chain c7n4(r7,r6) - r4c8(n4,n3) - r7c8(n3,n6) - r7c7(n6,n5) - r8c7(n5,n7) - r8c4(n7,n8) - r5c4(n8,n9) - r5c7(n9,.) =>r7c56<>4,r9c89<>4
Locked Candidates
step3:Naked Pair: in r5c6,r6c5 => r5c4<>8,r6c6<>58;stte

[denis_berthier]

.
SER = 9.0 (not for human solvers)

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Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 135678 13468  135678 ! 1478   9      123468 ! 1467   24678  247    !
   ! 16789  2      16789  ! 5      4678   1468   ! 3      4678   479    !
   ! 136789 134689 136789 ! 1478   34678  123468 ! 14679  5      2479   !
   +----------------------+----------------------+----------------------+
   ! 1369   5      1369   ! 149    46     7      ! 2      34     8      !
   ! 4      3689   36789  ! 89     2      568    ! 579    1      3579   !
   ! 12789  189    12789  ! 3      458    1458   ! 4579   47     6      !
   +----------------------+----------------------+----------------------+
   ! 35689  7      35689  ! 2      3458   3458   ! 456    346    1      !
   ! 23568  368    4      ! 78     1      358    ! 567    9      2357   !
   ! 1235   13     1235   ! 6      3457   9      ! 8      2347   23457  !
   +----------------------+----------------------+----------------------+

235 candidates (again, not for human solvers)

1) Simplest-first solution, in W6:
whip[4]: r4n4{c5 c8} - r9n4{c8 c9} - r7n4{c8 c6} - r2n4{c6 .} ==> r6c5≠4
whip[3]: r6c5{n5 n8} - r5c4{n8 n9} - b6n9{r5c7 .} ==> r6c7≠5
whip[1]: r6n5{c6 .} ==> r5c6≠5
whip[3]: r5c6{n8 n6} - r4c5{n6 n4} - b8n4{r7c5 .} ==> r7c6≠8
whip[5]: r9n4{c9 c5} - r4n4{c5 c4} - c4n9{r4 r5} - b6n9{r5c9 r6c7} - r6n4{c7 .} ==> r7c8≠4
whip[5]: c9n9{r3 r5} - b6n3{r5c9 r4c8} - r7c8{n3 n6} - b3n6{r1c8 r1c7} - c7n1{r1 .} ==> r3c7≠9
whip[1]: c7n9{r6 .} ==> r5c9≠9
z-chain[5]: c2n4{r1 r3} - c4n4{r3 r4} - c4n9{r4 r5} - b6n9{r5c7 r6c7} - b6n4{r6c7 .} ==> r1c8≠4
whip[5]: c4n4{r3 r4} - c4n9{r4 r5} - b6n9{r5c7 r6c7} - c2n9{r6 r3} - c2n4{r3 .} ==> r1c6≠4
whip[5]: c2n4{r1 r3} - c4n4{r3 r4} - c4n9{r4 r5} - c7n9{r5 r6} - c2n9{r6 .} ==> r1c7≠4
z-chain[5]: c4n4{r3 r4} - c4n9{r4 r5} - b6n9{r5c7 r6c7} - c7n4{r6 r7} - b8n4{r7c6 .} ==> r3c5≠4
whip[5]: r7c8{n6 n3} - r4c8{n3 n4} - c7n4{r6 r3} - c2n4{r3 r1} - c4n4{r1 .} ==> r7c7≠6
z-chain[5]: r7c7{n5 n4} - b8n4{r7c6 r9c5} - r4c5{n4 n6} - r5c6{n6 n8} - r6c5{n8 .} ==> r7c5≠5
whip[5]: c2n4{r1 r3} - c4n4{r3 r4} - c4n9{r4 r5} - c7n9{r5 r6} - c2n9{r6 .} ==> r1c9≠4
whip[5]: c7n1{r3 r1} - c4n1{r1 r4} - c4n9{r4 r5} - c7n9{r5 r6} - c2n9{r6 .} ==> r3c2≠1
z-chain[6]: c7n1{r3 r1} - c7n6{r1 r8} - r7c8{n6 n3} - b6n3{r4c8 r5c9} - r5n5{c9 c7} - r7c7{n5 .} ==> r3c7≠4
whip[4]: c7n4{r7 r6} - b5n4{r6c6 r4c4} - c4n9{r4 r5} - c7n9{r5 .} ==> r7c5≠4
z-chain[4]: b8n4{r7c6 r9c5} - c9n4{r9 r2} - c9n9{r2 r3} - r3n2{c9 .} ==> r3c6≠4
biv-chain[5]: r5c4{n8 n9} - b6n9{r5c7 r6c7} - c7n4{r6 r7} - b8n4{r7c6 r9c5} - c5n5{r9 r6} ==> r6c5≠8
naked-single ==> r6c5=5
biv-chain[4]: b8n5{r8c6 r7c6} - b8n4{r7c6 r9c5} - r4c5{n4 n6} - r5c6{n6 n8} ==> r8c6≠8
biv-chain[5]: r5c4{n8 n9} - b6n9{r5c7 r6c7} - c7n4{r6 r7} - b8n4{r7c6 r9c5} - b8n7{r9c5 r8c4} ==> r8c4≠8
singles ==> r8c4=7, r7c5=8
biv-chain[3]: c8n2{r1 r9} - b9n7{r9c8 r9c9} - r1c9{n7 n2} ==> r1c6≠2, r3c9≠2
hidden-single-in-a-row ==> r3c6=2
biv-chain[3]: b9n7{r9c8 r9c9} - r1c9{n7 n2} - c8n2{r1 r9} ==> r9c8≠3, r9c8≠4
z-chain[2]: r9n4{c5 c9} - b3n4{r3c9 .} ==> r2c5≠4
biv-chain[3]: b9n4{r7c7 r9c9} - b9n7{r9c9 r9c8} - r6c8{n7 n4} ==> r6c7≠4
stte

2) 4-step solution, in W8:
whip[8]: c4n9{r4 r5} - b6n9{r5c9 r6c7} - c2n9{r6 r3} - c2n4{r3 r1} - c4n4{r1 r3} - c7n4{r3 r7} - c9n4{r9 r2} - r2n9{c9 .} ==> r4c4≠1
hidden-single-in-a-block ==> r6c6=1
whip[1]: r2n1{c3 .} ==> r1c1≠1, r1c2≠1, r1c3≠1, r3c1≠1, r3c2≠1, r3c3≠1
hidden-single-in-a-column ==> r9c2=1
whip[4]: r4n4{c5 c8} - r9n4{c8 c9} - r7n4{c8 c6} - r2n4{c6 .} ==> r6c5≠4
whip[1]: r6n4{c8 .} ==> r4c8≠4
naked-single ==> r4c8=3
whip[6]: r7c8{n4 n6} - r7c7{n6 n5} - r8c7{n5 n7} - r5c7{n7 n9} - r5c4{n9 n8} - r8c4{n8 .} ==> r7c6≠4
whip[1]: b8n4{r9c5 .} ==> r2c5≠4, r3c5≠4, r4c5≠4
singles ==> r4c5=6, r4c4=4, r5c4=9, r6c7=9, r6c2=8, r6c5=5, r5c6=8, r3c2=9, r2c9=9, r1c2=4, r6c8=4, r7c8=6, r2c6=4
whip[1]: r2n6{c3 .} ==> r1c1≠6, r1c3≠6, r3c1≠6, r3c3≠6
whip[1]: r6n7{c3 .} ==> r5c3≠7
hidden-pairs-in-a-column: c7{n1 n6}{r1 r3} ==> r3c7≠4, r3c7≠7, r1c7≠7
stte

[m_b_metcalf]

SER = 9.0 (not for human solvers)

In fact, ED=9.0/9.0/8.0, which has been played only once in the Patterns Game. As for human solvers, there is a backdoor solution that a human might find.
Mike

Hidden Text: Show

4r3c9

[denis_berthier]

As for human solvers, there is a backdoor solution that a human might find.

Hidden Text: Show

4r3c9

Maybe. But using backdoors is generally considered as guessing.

[P.O.]

.
SER = 9.0 (not for human solvers)

it is not for a human solver it is for testing algorithms, and as yzfwsf’s solution shows it is simply solved with 2 chains disregarding the basics; my solution is also 2 chains + basics:

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n4b9p1289 => r9c5 <> 35
 r7c7=4 - r9n4{c89 c5}
 r7c8=4 - r9n4{c89 c5}
 r9c8=4 - c8n2{r9 r1} - 479r123c9 - r9n7{c9 c5}
 r9c9=4 - 279r123c9 - c8n2{r1 r9} - r9n7{c8 c5}
 
c4n9{r5 r4} - b5n1{r4c4 r6c6} - b5n4{r6c6 r46c5} - r9c5{n4 n7} - r8c4{n7 n8} => r5c4 <> 8
bte.


In fact, ED=9.0/9.0/8.0, which has been played only once in the Patterns Game. As for human solvers, there is a backdoor solution that a human might find.

it is this one, as for backdoors it has 5 after singles and 3 after singles + intersections:

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n4r3c9 n7r5c7 n7r6c3 n8r8c1 n7r9c8
n8r1c4 n3r7c3 n5r7c6


[denis_berthier]

.
The number of steps is totally irrelevant if you can't assign some complexity to each step - and this in a consistent way for all your patterns.

[P.O.]

.
The number of steps is totally irrelevant if you can't assign some complexity to each step - and this in a consistent way for all your patterns.

when i started posting solutions my goal was to minimize the number of eliminations to solve a puzzle, i didn't even do the intersections only the singles, then i noticed that the intersections were made without their eliminations being taken into account, so i did the same; then later i noticed that most players only offer a solution after what is called basics, that is intersections and subsets, have been done and considered the puzzle solved when only the basics remained, and even wherever a basic appears it was not taken into account, so why not and i even added the basic fish to the list of what can be disregarded;
a simplest-first solution is a large number of unnecessary eliminations, a shorter solution is to seek to perform only those that are necessary; so this is the game i'm playing at the moment: do not take into account the eliminations made by the basics, minimize the eliminations.

[denis_berthier]

most players

you mean a handful of players, most of whom use computer solvers.

a simplest-first solution is a large number of unnecessary eliminations, a shorter solution is to seek to perform only those that are necessary;

Your claims rely on pure nonsense:
- an elimination is rarely "unnecessary"; it makes the next eliminations easier;
- an elimination is rarely "necessary"; there are always lots of different resolution paths.

There's always a balance between the number of steps and the lengths of the chains used.

Otherwise, you could find a 1-step solution:

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FORCING[3]-T&E(S) applied to trivalue candidates n9r4c1, n9r4c3 and n9r4c4 :
===> 15 values decided in the three cases: n4r1c2 n5r6c5 n1r6c6 n1r9c2 n2r3c6 n7r8c4 n2r8c9 n7r2c5 n7r1c9 n8r7c5 n7r3c1 n2r6c1 n2r9c3 n5r1c3 n8r8c1
===> 133 candidates eliminated in the three cases: n1r1c1 n5r1c1 n7r1c1 n8r1c1 n1r1c2 n3r1c2 n6r1c2 n8r1c2 n1r1c3 n3r1c3 n6r1c3 n7r1c3 n8r1c3 n4r1c4 n7r1c4 n1r1c6 n2r1c6 n4r1c6 n8r1c6 n4r1c7 n6r1c7 n7r1c7 n4r1c8 n6r1c8 n7r1c8 n2r1c9 n4r1c9 n7r2c1 n8r2c1 n7r2c3 n8r2c3 n9r2c3 n4r2c5 n6r2c5 n8r2c5 n1r2c6 n6r2c6 n4r2c8 n7r2c8 n7r2c9 n1r3c1 n3r3c1 n6r3c1 n8r3c1 n9r3c1 n1r3c2 n3r3c2 n4r3c2 n6r3c2 n1r3c3 n6r3c3 n7r3c3 n9r3c3 n7r3c4 n8r3c4 n4r3c5 n7r3c5 n8r3c5 n1r3c6 n3r3c6 n4r3c6 n6r3c6 n8r3c6 n4r3c7 n7r3c7 n9r3c7 n2r3c9 n7r3c9 n6r4c1 n3r4c3 n1r4c4 n4r4c8 n8r5c2 n8r5c3 n9r5c3 n5r5c6 n9r5c7 n7r5c9 n9r5c9 n1r6c1 n7r6c1 n8r6c1 n9r6c1 n1r6c2 n9r6c2 n1r6c3 n2r6c3 n9r6c3 n4r6c5 n8r6c5 n4r6c6 n5r6c6 n8r6c6 n5r6c7 n7r6c7 n6r7c1 n8r7c1 n5r7c3 n6r7c3 n8r7c3 n3r7c5 n4r7c5 n5r7c5 n3r7c6 n8r7c6 n5r7c7 n6r7c7 n4r7c8 n2r8c1 n3r8c1 n5r8c1 n6r8c1 n8r8c2 n8r8c4 n8r8c6 n7r8c7 n3r8c9 n5r8c9 n7r8c9 n1r9c1 n2r9c1 n3r9c1 n3r9c2 n1r9c3 n3r9c3 n5r9c3 n5r9c5 n7r9c5 n2r9c8 n3r9c8 n2r9c9 n4r9c9 n7r9c9
stte

[P.O.]

hi Denis, stop playing on words try to understand what is being said.

[denis_berthier]

hi Denis, stop playing on words try to understand what is being said.

I'm not playing on any words. I'm just reading what you write.