The New Sudoku Players' Forum

[denis_berthier]

.
Diagonal cross 8.2

I proposed an easy (too easy?) and a difficult puzzle with the same "diagonal cross" pattern.
Here is an intermediate one.

Code: Select all

   +-------+-------+-------+
   ! . . 5 ! . . . ! 9 . . !
   ! . 2 . ! 6 . 1 ! . 7 . !
   ! 4 . . ! . 3 . ! . . 8 !
   +-------+-------+-------+
   ! . 3 . ! . . . ! . 2 . !
   ! . . 1 ! . . . ! 3 . . !
   ! . 9 . ! . . . ! . 6 . !
   +-------+-------+-------+
   ! 6 . . ! . 7 . ! . . 5 !
   ! . 5 . ! 8 . 2 ! . 9 . !
   ! . . 9 ! . . . ! 1 . . !
   +-------+-------+-------+
..5...9...2.6.1.7.4...3...8.3.....2...1...3...9.....6.6...7...5.5.8.2.9...9...1.. #  1254 FNBTHXY C24.m/S8.f
24 givens, SER = 8.2

[DEFISE]

W-rating =4 but here is a solution with only two whips[<=5] :

Single: 9r2c1
Alignment: 9c5b5 => -9r4c4 -9r4c6 -9r5c4 -9r5c6
Alignment: 1c8b3 => -1r1c9
Hidden pair: 26b3p37 => -3r1c9 -4r1c9 -5r3c7

whip[5]: r3c7{n2 n6}- r3c3{n6 n7}- r3c2{n7 n1}- r7n1{c2 c4}- c4n9{r7 .} => -2r3c4

Singles: 2r3c7, 6r1c9, 2r7c3, 2r9c9, 6r8c7, 7r8c9, 3r2c9, 8r2c3, 3r1c1, 1r8c1, 4r8c5, 5r2c5, 4r2c7, 1r1c8, 7r1c2, 6r3c3, 1r3c2, 5r3c8, 8r7c7, 4r7c2, 3r7c8, 9r7c6, 7r3c6, 9r3c4, 1r7c4, 3r8c3, 8r9c2, 6r5c2, 7r9c1, 6r9c5, 4r9c8, 8r5c8, 6r4c6, 7r5c4
Naked pair: 45b5p16 => -4r6c4 -5r6c4 -4r6c6 -5r6c6
Hidden pair: 19r4c59 => -8r4c5 -4r4c9
Single: 8r4c1

whip[4]: r5c1{n2 n5}- r5c6{n5 n4}- r1n4{c6 c4}- c4n2{r1 .} => -2r6c1
STTE

[pjb]

No single digit elimination for stte finish, so two uncomplicated chains:
(2)r9c9 = (2-6)r1c9 = (6)r1c2 - (6=1)r3c23 - (1)r7c2 = (1-9)r7c4 = (9-2)r3c4 = (2)r3c7 => -2 r1c9, -2 r7c7
(2=8)r1c5 - (8=4)r1c6 - (4=5)r5c6 - (5=2)r5c1 => -2 r5c5; stte

Phil

[denis_berthier]

No single digit elimination for stte finish,

Right (i.e. no BRT-anti-backdoor).
Moreover, no W1-anti-backdoor and no S-anti-backdoor.
Together with its medium difficulty level, that's the reason why I chose this puzzle among the 1,000 I generated for this pattern.

[Leren]

1 1/2 steps maybe ?

1.

Code: Select all

*-------------------------------------------------------------*
| 1378  1678  5    | 247    248    478   | 9     14-3  26     |
| 9     2     38   | 6      458    1     |a45    7    a34     |
| 4    b167  b67   | 2579   3      579   |b26   a15    8      |
|------------------+---------------------+--------------------|
| 578   3     4678 | 1457   145689 45678 | 4578  2     1479   |
| 2578  4678  1    | 2457   245689 45678 | 3     458   479    |
| 2578  9     2478 | 123457 12458  34578 | 4578  6     147    |
|------------------+---------------------+--------------------|
| 6     148   2348 | 1349   7      349   |c248  c348   5      |
| 137   5     347  | 8      146    2     | 467   9     467-3  |
| 2378  478   9    | 345    456    3456  | 1    c348   2467-3 |
*-------------------------------------------------------------*

(3=1) r2c79, r3c8 - (1=2) r3c237 - (2=3) r7c78, r9c8 => - 3 r1c8, r89c9; basics

1 1/2.

Code: Select all

*---------------------------------*
| 3  7 5  | 24  28   48 | 9  1 6  |
| 9  2 8  | 6   5    1  | 4  7 3  |
| 4  1 6  | 9   3    7  | 2  5 8  |
|---------+-------------+---------|
| 8  3 47 | 45  19   6  | 57 2 19 |
| 25 6 1  | 7   29   45 | 3  8 49 |
| 25 9 47 | 23 *2-18 38 | 57 6 14 |
|---------+-------------+---------|
| 6  4 2  | 1   7    9  | 8  3 5  |
| 1  5 3  | 8   4    2  | 6  9 7  |
| 7  8 9  | 35  6    35 | 1  4 2  |
*---------------------------------*

BUG + 1 => r6c6 = 2; stte

Leren