Easy tridagon or not ??

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Easy tridagon or not ??

Postby champagne » Fri Apr 25, 2025 7:16 am

Here is a puzzle from mith's file
It came as "hard" in my attempt to select puzzles of interest.
I am curious to see what our experts can do
(could not check if it has already been processed)

Code: Select all
8......25......9..2...951.8..952..8......4..1..4.81.9..3......2..1......67....45.
|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|
| 8         9         367      | 13467     13467     367      | 367       2         5        |
| 13457     1456      3567     | 1234678   13467     23678    | 9         3467      367      |
| 2         46        367      | 3467      9         5        | 1         3467      8        |
|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|
| 137       16        9        | 5         2         367      | 367       8         4        |
| 357       2568      235678   | 9         367       4        | 23567     367       1        |
| 357       256       4        | 367       8         1        | 23567     9         367      |
|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|
| 459       3         58       | 4678      4567      6789     | 678       1         2        |
| 459       2458      1        | 234678    34567     236789   | 3678      367       3679     |
| 6         7         28       | 1238      13        2389     | 4         5         39       |
|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|++++++++++++++++++++++++++++++|
champagne
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Re: Easy tridagon or not ??

Postby denis_berthier » Fri Apr 25, 2025 8:11 am

.
I would call it trivial if one uses the tridagon pattern:
Code: Select all
Resolution state after Singles and whips[1]:
   +----------------------+----------------------+----------------------+
   ! 8      9      367    ! 13467  13467  367    ! 367    2      5      !
   ! 13457  1456   3567   ! 23678  367    23678  ! 9      3467   367    !
   ! 2      46     367    ! 367    9      5      ! 1      3467   8      !
   +----------------------+----------------------+----------------------+
   ! 137    16     9      ! 5      2      367    ! 367    8      4      !
   ! 357    2568   235678 ! 9      367    4      ! 23567  367    1      !
   ! 357    256    4      ! 367    8      1      ! 23567  9      367    !
   +----------------------+----------------------+----------------------+
   ! 459    3      58     ! 4678   4567   6789   ! 678    1      2      !
   ! 459    2458   1      ! 234678 34567  236789 ! 3678   367    3679   !
   ! 6      7      28     ! 1238   13     2389   ! 4      5      39     !
   +----------------------+----------------------+----------------------+
185 candidates.


hidden-pairs-in-a-column: c7{n2 n5}{r5 r6} ==> r6c7≠7, r6c7≠6, r6c7≠3, r5c7≠7, r5c7≠6, r5c7≠3
hidden-pairs-in-a-row: r2{n2 n8}{c4 c6} ==> r2c6≠7, r2c6≠6, r2c6≠3, r2c4≠7, r2c4≠6, r2c4≠3
hidden-pairs-in-a-row: r1{n1 n4}{c4 c5} ==> r1c5≠7, r1c5≠6, r1c5≠3, r1c4≠7, r1c4≠6, r1c4≠3

Code: Select all
   +----------------------+----------------------+----------------------+
   ! 8      9      367    ! 14     14     367#   ! 367#   2      5      !
   ! 13457  1456   3567   ! 28     367#   28     ! 9      3467   367#   !
   ! 2      46     367    ! 367#   9      5      ! 1      3467#@ 8      !
   +----------------------+----------------------+----------------------+
   ! 137    16     9      ! 5      2      367#   ! 367#   8      4      !
   ! 357    2568   235678 ! 9      367#   4      ! 25     367#   1      !
   ! 357    256    4      ! 367#   8      1      ! 25     9      367#   !
   +----------------------+----------------------+----------------------+
   ! 459    3      58     ! 4678   4567   6789   ! 678    1      2      !
   ! 459    2458   1      ! 234678 34567  236789 ! 3678   367    3679   !
   ! 6      7      28     ! 1238   13     2389   ! 4      5      39     !
   +----------------------+----------------------+----------------------+
tridagon for digits 3, 6 and 7 in blocks:
        b3, with cells (marked #): r3c8 (target cell, marked @), r2c9, r1c7
        b2, with cells (marked #): r3c4, r2c5, r1c6
        b6, with cells (marked #): r5c8, r6c9, r4c7
        b5, with cells (marked #): r5c5, r6c4, r4c6
 ==> r3c8≠3,6,7

S2-tte (singles + 1 x-wing)

PS: I remember talking about a T&E(3) puzzle falling down to W2 after using the tridagon. Not sure if it was that one or a different one.
.
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Re: Easy tridagon or not ??

Postby champagne » Fri Apr 25, 2025 8:45 am

In fact my filter has 2 starts here, one for each TH.
Using the upper TH, the puzzle is classified easy,
using the lower TH, the code keeps the upper TH untouched.
champagne
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Re: Easy tridagon or not ??

Postby denis_berthier » Fri Apr 25, 2025 9:27 am

.
which "lower TH", which "code"?
I can see only one tridagon.
.
denis_berthier
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Re: Easy tridagon or not ??

Postby champagne » Fri Apr 25, 2025 10:08 am

this puzzle has a lower TH "degenerated" with several guardians boxes 5689.

In my previous example, the second TH was solved, here it is not.

I am convinced that one day, in such a case, the "easy moves" will push to solve first the TH keeping untouched the other one.

And to select puzzles of interest, I have to consider such cases
champagne
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Joined: 02 August 2007
Location: France Brittany


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