The New Sudoku Players' Forum

[shye]

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+-------+-------+-------+
| 4 5 . | . . . | 6 7 . |
| 6 . 8 | . . . | . . 9 |
| . 9 7 | . . 1 | 8 . . |
+-------+-------+-------+
| . . . | 3 . . | . 4 . |
| . . . | . . 6 | . . 7 |
| . . 2 | . 4 . | . . . |
+-------+-------+-------+
| 5 . 9 | . . . | 7 1 . |
| 7 . . | 9 . . | 2 . 8 |
| . 8 . | . 7 . | . 9 3 |
+-------+-------+-------+
45....67.6.8.....9.97..18.....3...4......6..7..2.4....5.9...71.7..9..2.8.8..7..93

estimated rating: 4.2
too easy?

[jco]

Two steps for me.

Code: Select all

.----------------------------------------------------------------------.
| 4      5      13     | 28     2389   2389   |  6       7     e(12)   |
| 6      123    8      | 2457   235    23457  |a(4)35-1 e(235)   9     |
| 23     9      7      | 2456   2356   1      |  8      e(235)   245   |
|----------------------+----------------------+------------------------|
| 189    167    156    | 3      12589  25789  |  159      4      1256  |
| 1389   134    1345   | 1258   12589  6      |  1359     2358   7     |
| 1389   1367   2      | 1578   4      5789   |  1359     3568   156   |
|----------------------+----------------------+------------------------|
| 5      2346   9      | 2468   2368   2348   |  7        1      46    |
| 7      1346   1346   | 9      1356   345    |  2      d(5)6    8     |
| 12     8      146    | 12456  7      245    |c(45)      9      3     |
'----------------------------------------------------------------------'


1. (4)r2c7 = (4-5)r9c7 = (5)r8c8 - (5=321)b3p358 => -1 r2c7 [15 placements and basics]
---

Code: Select all

.-----------------------------------------------------------.
| 4     5     3     | 28    289   289   | 6     7     1     |
| 6     1     8     | 7     35    345   | 345   2     9     |
| 2     9     7     | 456   356   1     | 8     35    45    |
|-------------------+-------------------+-------------------|
| 89    6     15    | 3     589   7     | 159   4     2     |
| 389   4     15    | 1258  2589  6     | 1359  358   7     |
| 389   7     2     | 158   4     589   | 1359  3568  56    |
|-------------------+-------------------+-------------------|
| 5     2     9     | 468   368   348   | 7     1     46    |
| 7     3     4-6   | 9     1     45    | 2    c56    8     |
| 1     8    a46    | 2456  7     245   |b45    9     3     |
'-----------------------------------------------------------'

2. Y-wing (6=4)r9c3 - (4=5)r9c7 - (5=6)r8c8 => -6 r8c3; ste

Hidden Text: Show

The second elimination is available at step 1 as
[(6=4)r9c3 - (4=5)r9c7 - (5=6)r8c8] = (1)r9c3 - (1=23)r39c1 - (3=12)r1c39 - (2=356)r238c8
=> -6 r8c23
but does not solve the puzzle,

EDIT: corrected formatting of grid and added hidden comment.

[totuan]

Code: Select all

 *--------------------------------------------------------------------*
 | 4      5     #13A    | 28     2389   2389   | 6      7     #12A    |
 | 6     #123    8      | 2457   235    23457  | 1345  #235    9      |
 |#23     9      7      | 2456   2356   1      |#8      235    245    |
 |----------------------+----------------------+----------------------|
 | 189    167    156    | 3      12589  25789  | 159    4      1256   |
 | 1389   134    1345   | 1258   12589  6      | 1359   2358   7      |
 | 1389   1367   2      | 1578   4      5789   | 1359   3568   156    |
 |----------------------+----------------------+----------------------|
 |#5      2346   9      | 2468   2368   2348   | 7     #1      46     |
 | 7     #1346   1346   | 9      1356   345    |#2      56     8      |
 | 12     8     #146A   | 12456  7      245    | 45     9     #3A     |
 *--------------------------------------------------------------------*

Not sure…! But, it seems look like “reverse tridagon” on using given values
Form tridagon (123) #-marked cells, by 8r3c7 & 5r7c1 => one of digit (1|2|3) at rectangle A-marked cells must be twice => r1c3=3

Thanks for the puzzle!
totuan

[Hajime]

No basics needed like naked/hidden subsets and pointing/claiming. Only several XY-wings to solve it.
Maybe less XY-wings when applying in different order.

Hidden Text: Show

Code: Select all

[1,0]XY-wing [3 cells] (1=3)r1c3-(3=2)r3c1-(2=1)r9c1 => (-1)r8c3 (-1)r9c3
[2,0]XY-wing [3 cells] (2=1)r1c9-(1=3)r1c3-(3=2)r3c1 => (-2)r3c9 (-2)r3c8
[3,0]XY-wing [3 cells] (5=4)r3c9-(4=6)r7c9-(6=5)r8c8 => (-5)r3c8 (-5)r2c8
[4,1] r3c8=3 Naked Single
[5,2] r2c8=2 Naked Single
[5,3] r3c1=2 Naked Single
[5,4] r9c1=1 Naked Single
[6,5] r1c9=1 Naked Single
[7,6] r1c3=3 Naked Single
[7,7] r2c2=1 Naked Single
[8,8] r8c5=1 Hidden Single in row 8
[8,9] r7c2=2 Hidden Single in col 2
[8,10] r4c9=2 Hidden Single in col 9
[8,11] r8c2=3 Hidden Single in box 7
[9,12] r5c2=4 Naked Single
[10,12]XY-chain [3 links] (5=4)r2c7-(4=5)r9c7 => (-5)r4c7 (-5)r5c7 (-5)r6c7
[11,12]XY-chain [3 links] (6=7)r4c2-(7=6)r6c2 => (-6)r4c3
[12,13] r4c2=6 Hidden Single in row 4
[12,14] r4c6=7 Hidden Single in row 4
[12,15] r6c2=7 Hidden Single in row 6
[12,16] r2c4=7 Hidden Single in col 4
[13,16]XY-wing [3 cells] (6=5)r3c5-(5=4)r3c9-(4=6)r7c9 => (-6)r7c5
[14,17] r3c5=6 Hidden Single in col 5
[15,17]XY-wing [3 cells] (4=6)r7c9-(6=5)r8c8-(5=4)r8c6 => (-4)r7c4 (-4)r7c6
[16,18] r7c9=4 Hidden Single in row 7
[16,19] r7c4=6 Hidden Single in row 7
[16,20] r9c3=6 Hidden Single in row 9
[16,21] r8c3=4 Hidden Single in col 3
[16,22] r2c7=4 Hidden Single in col 7
[16,23] r9c7=5 Hidden Single in col 7
[16,24] r6c9=6 Hidden Single in col 9
[16,25] r3c4=4 Hidden Single in box 2
[16,26] r3c9=5 Hidden Single in box 3
[16,27] r9c6=4 Hidden Single in box 8
[16,28] r8c6=5 Hidden Single in box 8
[16,29] r8c8=6 Hidden Single in box 9
[17,30] r2c6=3 Naked Single
[17,31] r7c6=8 Naked Single
[17,32] r9c4=2 Naked Single
[18,33] r1c4=8 Naked Single
[18,34] r2c5=5 Naked Single
[18,35] r6c6=9 Naked Single
[18,36] r7c5=3 Naked Single
[19,37] r1c6=2 Naked Single
[19,38] r4c5=8 Naked Single
[19,39] r5c5=2 Naked Single
[20,40] r1c5=9 Naked Single
[20,41] r4c1=9 Naked Single
[20,42] r4c7=1 Naked Single
[20,43] r6c7=3 Naked Single
[21,44] r4c3=5 Naked Single
[21,45] r5c3=1 Naked Single
[21,46] r5c4=5 Naked Single
[21,47] r5c7=9 Naked Single
[21,48] r5c8=8 Naked Single
[21,49] r6c1=8 Naked Single
[21,50] r6c4=1 Naked Single
[21,51] r6c8=5 Naked Single
[22,52] r5c1=3 Naked Single


[P.O.]

Code: Select all

4      5      13     28     2389   2389   6      7      12             
6      123    8      2457   235    23457  1345   235    9               
23     9      7      2456   2356   1      8      235    245             
189    167    156    3      12589  25789  159    4      1256           
1389   134    1345   1258   12589  6      1359   2358   7               
1389   1367   2      1578   4      5789   1359   3568   156             
5      2346   9      2468   2368   2348   7      1      46             
7      1346   1346   9      1356   345    2      56     8               
12     8      146    12456  7      245    45     9      3         

5r8c8 => r9c7 <> 4,5
 r8c8=5 - 23r23c8 - r1c9{n2 n1} - r2n1{c7 c2} - c2n2{r2 r7} - r7n3{c2 c56} - r8c6{n35 n4} - r7n4{c46 c9}
=> r8c8 <> 5
ste.


[shye]

hajime matched my solution
just wanted to make something on the simpler side, 4 y-wings (only 3 needed), and see if anyone could find something shorter thats still within reason :3
next puzzle will be a hard one to make up for it