The New Sudoku Players' Forum

by **Yogi** » Mon Feb 28, 2022 11:56 pm

...7.5.............7.619.3.3.6...9.8...2.3....1.....2..9.....1.1.7.5.6.44..1.8..5

Code: Select all: +---+---+---+ |...|7.5|...| |...|...|...| |.7.|619|.3.| +---+---+---+ |3.6|...|9.8| |...|2.3|...| |.1.|...|.2.| +---+---+---+ |.9.|...|.1.| |1.7|.5.|6.4| |4..|1.8|..5| +---+---+---+

Not too hard - for those not ready to reach for the sky . . . just yet.

by **RSW** » Tue Mar 01, 2022 2:51 am

Easily solved with basics only. So...
After singles only:

Code: Select all: +--------------------+---------------+-----------------+ | 2689 a3468 123489 | 7 238 5 | 148 4689 169 | | 25689 a3568 123589 | 38 238 4 | 1578 56789 1679 | |a58 7 a458 | 6 1 9 | 458 3 2 | +--------------------+---------------+-----------------+ | 3 2 6 | 45 47 1 | 9 457 8 | | 5789 458 4589 | 2 46789 3 | 1457 4567 167 | | 5789 1 4589 | 4589 46789 67 | 3457 2 367 | +--------------------+---------------+-----------------+ | 2568 9 2358 | 34 3467 67 | 2378 1 37 | | 1 8-3 7 | 39 5 2 | 6 89 4 | | 4 b36 23 | 1 3679 8 | 237 79 5 | +--------------------+---------------+-----------------+

(3=4586)b1p2579-(6=3)r9c2 => -3r8c2; stte

by **jco** » Tue Mar 01, 2022 3:25 am

After singles (to 31 known numbers)

Code: Select all: .-----------------------------------------------------------------------------. | 2689 3468 123489 | 7 238 5 | 148 468-9 169 | | 25689 3568 123589 | 38 238 4 | 1578 5678-9 1679 | | 58 7 458 | 6 1 9 | 458 3 2 | |-------------------------+-------------------------+-------------------------| | 3 2 6 | 45 47 1 | 9 457 8 | | 5789 458 4589 | 2 46789 3 | 1457 4567 167 | | 5789 1 4589 | 4589 46789 67 | 3457 2 367 | |-------------------------+-------------------------+-------------------------| | 2568 9 2358 | 34 3467 67 | 2378 1 37 | | 1 38 7 | 39 5 2 | 6 #8(9) 4 | | 4 36 23 | 1 3679 8 | 237 #7(9) 5 | '-----------------------------------------------------------------------------'

0.1 (9)r8c8 = (9)r9c8 => -9 r12c8 [LC elimination]

Code: Select all: .-----------------------------------------------------------------------------. | 2689 3468 123489 | 7 238 5 | 148 468 169 | | 25689 3568 123589 | 38 238 4 | 1578 5678 1679 | | 58 7 458 | 6 1 9 | 458 3 *2 | |-------------------------+-------------------------+-------------------------| | 3 2 6 | 45 47 1 | 9 457 *8 | | 5789 458 4589 | 2 46789 3 | 1457 4567 167 | | 5789 1 4589 | 4589 46789 67 | 3457 2 367 | |-------------------------+-------------------------+-------------------------| | 258-6 9 258-3 |#34 #3467 #67 | 28-37 1 #37 | | 1 38 7 | 39 *5 *2 | 6 89 4 | | 4 36 23 | 1 3679 *8 | 237 79 *5 | '-----------------------------------------------------------------------------'

0.2 HT: (258)r7c137 => -6 r7c1, -3 r7c3, -37 r7c7 (& +6 r9c2)

[OR NQ: (3467)r7c4569 with the same eliminations and placement]

Code: Select all: .-----------------------------------------------------------------------------. | 269-8 #348 129-348 | 7 238 5 | 148 468 169 | | 269-58 #358 129-358 | 38 238 4 | 1578 5678 1679 | |#58 7 #458 |*6 *1 *9 | 458 3 *2 | |-------------------------+-------------------------+-------------------------| | 3 *2 6 | 5 47 1 | 9 47 8 | | 5789 458 4589 | 2 46789 3 | 1457 4567 167 | | 5789 *1 4589 | 489 46789 67 | 3457 2 367 | |-------------------------+-------------------------+-------------------------| | 258 *9 258 | 34 3467 67 | 28 1 37 | | 1 38 7 | 39 5 2 | 6 89 4 | | 4 *6 23 | 1 379 8 | 237 79 5 | '-----------------------------------------------------------------------------'

0.3 HQ: (1269)r12c1,r12c3 => -3 r12c3, -4 r1c3, -5 r2c13, -8 r12c13; ste

[OR NQ: (3458)r12c2,r3c13 with the same eliminations]

by **P.O.** » Tue Mar 01, 2022 10:12 am

Code: Select all: grid: "...7.5.............7.619.3.3.6...9.8...2.3....1.....2..9.....1.1.7.5.6.44..1.8..5" (" r3c9b3 n2 " " r8c6b8 n2 " " r2c6b2 n4 " " r4c6b5 n1 " " r4c2b4 n2 ") intersections: ((((9 0) (8 8 9) (8 9)) ((9 0) (9 8 9) (7 9)))) QUAD ROW: ((7 4 8) (3 4)) ((7 5 8) (3 4 6 7)) ((7 6 8) (6 7)) ((7 9 9) (3 7)) (((7 1 7) (2 5 6 8)) ((7 3 7) (2 3 5 8)) ((7 7 9) (2 3 7 8))) (" r9c2b7 n6 ") QUAD BOX: ((1 2 1) (3 4 8)) ((2 2 1) (3 5 8)) ((3 1 1) (5 8)) ((3 3 1) (4 5 8)) (((1 1 1) (2 6 8 9)) ((1 3 1) (1 2 3 4 8 9)) ((2 1 1) (2 5 6 8 9)) ((2 3 1) (1 2 3 5 8 9))) (" r9c3b7 n3 " " r8c2b7 n8 " " r8c8b9 n9 " " r9c8b9 n7 " " r7c9b9 n3 " " r8c4b8 n3 " " r9c5b8 n9 " " r9c7b9 n2 " " r2c4b2 n8 " " r7c4b8 n4 " " r7c7b9 n8 " " r4c4b5 n5 " " r4c8b6 n4 " " r6c4b5 n9 " " r4c5b5 n7 " " r6c6b5 n6 " " r6c9b6 n7 " " r7c5b8 n6 " " r7c6b8 n7 " " r6c7b6 n3 " " r2c7b3 n7 " " r5c1b4 n7 " " r1c8b3 n8 " " r5c3b4 n9 " " r5c5b5 n8 " " r6c5b5 n4 " " r5c2b4 n4 " " r3c3b1 n4 " " r2c2b1 n5 " " r6c3b4 n8 " " r3c1b1 n8 " " r1c2b1 n3 " " r1c5b2 n2 " " r2c5b2 n3 " " r2c8b3 n6 " " r3c7b3 n5 " " r5c7b6 n1 " " r5c8b6 n5 " " r5c9b6 n6 " " r6c1b4 n5 " " r7c1b7 n2 " " r7c3b7 n5 " " r1c3b1 n1 " " r1c7b3 n4 " " r1c9b3 n9 " " r2c1b1 n9 " " r2c3b1 n2 " " r2c9b3 n1 " " r1c1b1 n6 ") SOLVED WITH BASICS. 6 3 1 7 2 5 4 8 9 9 5 2 8 3 4 7 6 1 8 7 4 6 1 9 5 3 2 3 2 6 5 7 1 9 4 8 7 4 9 2 8 3 1 5 6 5 1 8 9 4 6 3 2 7 2 9 5 4 6 7 8 1 3 1 8 7 3 5 2 6 9 4 4 6 3 1 9 8 2 7 5

Website · by **denis_berthier** » Sun Mar 06, 2022 5:32 am

.
SER = 5.0

Code: Select all: Resolution state after Singles and whips[1]: +----------------------+----------------------+----------------------+ ! 2689 3468 123489 ! 7 238 5 ! 148 468 169 ! ! 25689 3568 123589 ! 38 238 4 ! 1578 5678 1679 ! ! 58 7 458 ! 6 1 9 ! 458 3 2 ! +----------------------+----------------------+----------------------+ ! 3 2 6 ! 45 47 1 ! 9 457 8 ! ! 5789 458 4589 ! 2 46789 3 ! 1457 4567 167 ! ! 5789 1 4589 ! 4589 46789 67 ! 3457 2 367 ! +----------------------+----------------------+----------------------+ ! 2568 9 2358 ! 34 3467 67 ! 2378 1 37 ! ! 1 38 7 ! 39 5 2 ! 6 89 4 ! ! 4 36 23 ! 1 3679 8 ! 237 79 5 ! +----------------------+----------------------+----------------------+ 167 candidates

1) simplest-first solution, in S4+W3:

Code: Select all: finned-x-wing-in-columns: n5{c2 c8}{r2 r5} ==> r5c7≠5 finned-x-wing-in-columns: n4{c2 c8}{r1 r5} ==> r5c7≠4 hidden-triplets-in-a-row: r7{n2 n5 n8}{c7 c3 c1} ==> r7c7≠7, r7c7≠3, r7c3≠3, r7c1≠6 hidden-single-in-a-block ==> r9c2=6 biv-chain[3]: r2c4{n8 n3} - r8n3{c4 c2} - r8n8{c2 c8} ==> r2c8≠8 biv-chain[3]: r3c1{n8 n5} - c2n5{r2 r5} - c2n4{r5 r1} ==> r1c2≠8 biv-chain[3]: r1c2{n4 n3} - r8c2{n3 n8} - c8n8{r8 r1} ==> r1c8≠4 whip[1]: c8n4{r5 .} ==> r6c7≠4 biv-chain[3]: r4c5{n4 n7} - c6n7{r6 r7} - r7n6{c6 c5} ==> r7c5≠4 singles ==> r7c4=4, r4c4=5 x-wing-in-columns: n5{c2 c8}{r2 r5} ==> r5c3≠5, r5c1≠5, r2c7≠5, r2c3≠5, r2c1≠5 finned-x-wing-in-columns: n3{c4 c2}{r8 r2} ==> r2c3≠3 biv-chain[3]: c3n3{r1 r9} - r8c2{n3 n8} - c8n8{r8 r1} ==> r1c3≠8 biv-chain[3]: r6n3{c7 c9} - r7c9{n3 n7} - c6n7{r7 r6} ==> r6c7≠7 z-chain[3]: b1n6{r2c1 r1c1} - r1c8{n6 n8} - b2n8{r1c5 .} ==> r2c1≠8 z-chain[3]: r2c4{n8 n3} - r2c2{n3 n5} - r3c1{n5 .} ==> r2c3≠8 naked-quads-in-a-block: b1{r1c2 r2c2 r3c1 r3c3}{n4 n3 n8 n5} ==> r1c3≠4, r1c3≠3, r1c1≠8 stte

2) 2-step solution in W4:

Code: Select all: biv-chain[4]: r3c1{n8 n5} - c2n5{r2 r5} - c2n4{r5 r1} - r3n4{c3 c7} ==> r3c7≠8 whip[1]: r3n8{c3 .} ==> r1c1≠8, r1c2≠8, r1c3≠8, r2c1≠8, r2c2≠8, r2c3≠8 whip[4]: c2n5{r5 r2} - r3n5{c3 c7} - r3n4{c7 c3} - b4n4{r5c3 .} ==> r5c2≠8 stte

N2H 50