The New Sudoku Players' Forum

by **Leren** » Thu Jul 01, 2021 10:43 am

Code: Select all: *-----------* |4..|..6|17.| |.7.|4..|...| |...|..8|.64| |---+---+---| |82.|...|..3| |.96|.13|.8.| |...|5.4|9..| |---+---+---| |9..|..5|...| |.6.|7..|.35| |.4.|...|79.| *-----------* 4....617..7.4..........8.6482......3.96.13.8....5.49..9....5....6.7...35.4....79.

by **pjb** » Thu Jul 01, 2021 11:40 am

Code: Select all: 4 38 289 | 39 5 6 | 1 7 289 6 7 189 | 4 239 12 | 38 5 89 12-3 5 129 | 139 7 8 |d23 6 4 ------------------------+----------------------+--------------------- 8 2 4 | 69 69 7 | 5 1 3 5 9 6 | 2 1 3 | 4 8 7 7 1 3 | 5 8 4 | 9 2 6 ------------------------+----------------------+--------------------- 9 38 7 | 138 23 5 | 6 4 128 b12 6 b128 | 7 4 9 |c28 3 5 a23 4 5 | 1368 236 12 | 7 9 128

(3=2)r9c1 - (2)r8c13 = (2)r8c7 - (2=3)r3c7 => -3 r3c1; stte

Phil

by **jco** » Thu Jul 01, 2021 1:42 pm

Code: Select all: .-------------------------------------------. | 4 a38 289 | 9-3 5 6 | 1 7 289 | | 6 7 189 | 4 d239 12 |d38 5 89 | | 123 5 129 | 139 7 8 | 23 6 4 | |--------------+---------------+------------| | 8 2 4 | 69 69 7 | 5 1 3 | | 5 9 6 | 2 1 3 | 4 8 7 | | 7 1 3 | 5 8 4 | 9 2 6 | |--------------+---------------+------------| | 9 b38 7 | 138 23 5 | 6 4 128 | | 12 6 b128 | 7 4 9 |c28 3 5 | | 23 4 5 | 1368 236 12 | 7 9 128 | '-------------------------------------------'

(3)r1c2 = (38)b7p26 - (8)r8c7 = (83)r2c75 => -3 r1c4; ste

by **SteveG48** » Thu Jul 01, 2021 1:58 pm

Code: Select all: *------------------------------------------------------------* | 4 38 289 | 39 5 6 | 1 7 289 | | 6 7 189 | 4 239 12 | 38 5 89 | | c123 5 129 | 139 7 8 |b23 6 4 | *--------------------+-------------------+-------------------| | 8 2 4 | 69 69 7 | 5 1 3 | | 5 9 6 | 2 1 3 | 4 8 7 | | 7 1 3 | 5 8 4 | 9 2 6 | *--------------------+-------------------+-------------------| | 9 38 7 | 138 23 5 | 6 4 128 | |ac12 6 a128 | 7 4 9 |b28 3 5 | | 3-2 4 5 | 1368 236 12 | 7 9 128 | *------------------------------------------------------------*

2r8c13 = (23)r38c7 - (3=12)r38c1 => -2 r9c1 ; stte

by **P.O.** » Thu Jul 01, 2021 4:36 pm

Code: Select all: after singles: 4 38 2389 39 5 6 1 7 289 6 7 12389 4 239 12 238 5 289 c12+3 5 1239 139 7 8 d+2-3 6 4 8 2 4 69 69 7 5 1 3 5 9 6 2 1 3 4 8 7 7 13 13 5 8 4 9 2 6 9 138 7 138 23 5 6 4 128 a1-2 6 a1-28 7 4 9 ×28 3 5 b1+2-3 4 5 1368 236 12 7 9 128 depth: 2 candidate: 2 from cell (((8 7 9) (2 8))) ((2 0 1 0) ((8 1 7) (1 2)) ((8 3 7) (1 2 8))) if neither is 2 ((2 0) (9 1 7) (1 2 3)) R9C1 is 2 ((3 1 10) (3 1 1) (1 2 3)) R3C1 is 3 ((2 2 9) (3 7 3) (2 3)) R3C7 is 2 ste.

Website · by **denis_berthier** » Tue Jul 06, 2021 4:04 am

.
(find-sudoku-1-steppers-wrt-W1 "4....617..7.4..........8.6482......3.96.13.8....5.49..9....5....6.7...35.4....79.")

Code: Select all: Resolution state after Singles and whips[1]: +----------------+----------------+----------------+ ! 4 38 289 ! 39 5 6 ! 1 7 289 ! ! 6 7 189 ! 4 239 12 ! 38 5 89 ! ! 123 5 129 ! 139 7 8 ! 23 6 4 ! +----------------+----------------+----------------+ ! 8 2 4 ! 69 69 7 ! 5 1 3 ! ! 5 9 6 ! 2 1 3 ! 4 8 7 ! ! 7 1 3 ! 5 8 4 ! 9 2 6 ! +----------------+----------------+----------------+ ! 9 38 7 ! 138 23 5 ! 6 4 128 ! ! 12 6 128 ! 7 4 9 ! 28 3 5 ! ! 23 4 5 ! 1368 236 12 ! 7 9 128 ! +----------------+----------------+----------------+

There is an impressive number of easy 1-step solutions:

1) Using chains of length 3:

Code: Select all: z-chain[3]: b7n2{r8c3 r9c1} - c1n3{r9 r3} - r3c7{n3 .} ==> r8c7 ≠ 2 stte

Code: Select all: z-chain[3]: c1n3{r9 r3} - r3c7{n3 n2} - r8n2{c7 .} ==> r9c1 ≠ 2 stte

Code: Select all: whip[3]: r9c1{n3 n2} - r8n2{c3 c7} - r3c7{n2 .} ==> r3c1 ≠ 3 stte

Code: Select all: whip[3]: c7n2{r3 r8} - b7n2{r8c3 r9c1} - c1n3{r9 .} ==> r3c7 ≠ 3 stte

2) Using only bivaue-chains of length 4:

Code: Select all: biv-chain[4]: r1n3{c2 c4} - r2n3{c5 c7} - c7n8{r2 r8} - b7n8{r8c3 r7c2} ==> r1c2 ≠ 8, r7c2 ≠ 3 stte

Code: Select all: biv-chain[4]: r1c2{n3 n8} - b7n8{r7c2 r8c3} - c7n8{r8 r2} - r2n3{c7 c5} ==> r1c4 ≠ 3 stte

Code: Select all: biv-chain[4]: r2c7{n3 n8} - r8n8{c7 c3} - c2n8{r7 r1} - r1n3{c2 c4} ==> r2c5 ≠ 3 stte

Code: Select all: biv-chain[4]: r2n3{c7 c5} - r1n3{c4 c2} - c2n8{r1 r7} - r8n8{c3 c7} ==> r2c7 ≠ 8 stte

Code: Select all: biv-chain[4]: r7c2{n8 n3} - b1n3{r1c2 r3c1} - b3n3{r3c7 r2c7} - c7n8{r2 r8} ==> r8c3 ≠ 8, r7c9 ≠ 8 stte

by **RSW** » Wed Jul 07, 2021 3:36 am

Code: Select all: +------------+-------------+-----------+ | 4 38 289 | 39 5 6 | 1 7 289 | | 6 7 189 | 4 239 12 | 38 5 89 | |b123 5 129 | 139 7 8 |a23 6 4 | +------------+-------------+-----------+ | 8 2 4 | 69 69 7 | 5 1 3 | | 5 9 6 | 2 1 3 | 4 8 7 | | 7 1 3 | 5 8 4 | 9 2 6 | +------------+-------------+-----------+ | 9 38 7 | 138 23 5 | 6 4 128 | |d12 6 d128 | 7 4 9 |*8-2 3 5 | |c23 4 5 | 1368 236 12 | 7 9 128 | +------------+-------------+-----------+

(2=3)r3c7-(3)r3c1=(3-2)r9c1=(2)r8c13 => -2r8c7; ste

Leren's Puzzles 48