The New Sudoku Players' Forum

[Mauriès Robert]

Hi all,
Here is the puzzle that I suggest you solve, being myself in search of the best resolution.

..38.96..5....3.9........8...6..5..7..1.6.5..4..7..1...4........1.5....9..21.78..

Hidden Text: Show

[DEFISE]

This puzzle is in W6.
Here is a path in gW9 to greatly reduce the number of chains.
After basics :

Code: Select all

|-----------------------------------------------------------|
| 1     27    3     | 8     2457  9     | 6     2457  245   |
| 5     2678  478   | 246   247   3     | 247   9     1     |
| 2679  2679  479   | 246   2457  1     | 2347  8     2345  |
|-----------------------------------------------------------|
| 238   238   6     | 234   1     5     | 9     234   7     |
| 2379  2379  1     | 2349  6     248   | 5     234   2348  |
| 4     2359  59    | 7     2389  28    | 1     236   2368  |
|-----------------------------------------------------------|
| 36789 4     5789  | 239   2389  268   | 237   1     2356  |
| 3678  1     78    | 5     2348  2468  | 2347  23467 9     |
| 369   3569  2     | 1     349   7     | 8     3456  3456  |
|-----------------------------------------------------------|

whip[9]: c8n7{r1 r8}- r8c3{n7 n8}- r2c3{n8 n4}- c3n7{r2 r7}- r7n5{c3 c9}- r3n5{c9 c5}- r3n7{c5 c7}- r2c7{n7 n2}- b9n2{r7c7 .}
=> -7r1c2
Single(s): 2r1c2
whip[6]: r4c2{n3 n8}- r2n8{c2 c3}- r8c3{n8 n7}- c8n7{r8 r1}- c8n5{r1 r9}- c2n5{r9 .} => -3r6c2
Naked pairs: 59r6c23 => -9r6c5
Single(s): 9r5c4
g-whip[8]: c4n3{r7 r4}- c4n4{r4 r123}- r1n4{c5 c789}- c7n4{r2 r8}- r8n2{c7 c8}- r4c8{n2 n4}- r5c8{n4 n3}- r6n3{c8 .} => -2r7c4
Single(s): 3r7c4, 3r6c5
Box/Line: 8c5b8 => -8r7c6 -8r8c6
whip[7]: r7c6{n2 n6}- r7c9{n6 n5}- r1c9{n5 n4}- c7n4{r2 r8}- b9n7{r8c7 r8c8}- r8n3{c8 c1}- r8n6{c1 .} => -2r7c7
Single(s): 7r7c7, 7r1c8, 5r9c8, 5r7c3, 9r6c3, 5r6c2
Naked pairs: 26r7c69 => -6r7c1 -2r7c5
whip[8]: c6n4{r8 r5}- r4c4{n4 n2}- c1n2{r4 r5}- r5c8{n2 n3}- r8n3{c8 c1}- r4c1{n3 n8}- b7n8{r7c1 r8c3}- r8n7{c3 .} => -4r8c7
Box/Line: 4c7b3 => -4r1c9 -4r3c9
STTE

[Mauriès Robert]

Hello François,
Thank you for your 5 whips resolution.
By hand, mine below is not optimized in terms of number of steps, but it has the particularity that at no time does it call on the invalidity of the chains.
After reducing the puzzle using basic techniques :
(-4r9c5)->4r9c89->4r23c7->4r1c5->… => -4r238c5
(-4r4c8)->4r4c4->4r8c6->4r1c5->... => -4r18c8
(-2r1c2)->(7r1c2->7r8c8)->7r7c3->5r7c9->5r1c8->… => -2r1c8
(-2r1c2)->(7r1c2->5r1c8->5r3c5->7r2c5 et 7r8c8->8r8c3->4r2c3)->2r2c7->... => -2r1c9
(-2r1c2)->(7r1c2->7r8c8)->7r7c3->5r7c9->2r78c7->2r3c9->... -2r3c12 => -2r456c2
(-3r4c2)->8r4c2->8r2c3->7r8c3->7r1c8->5r9c8->5r6c2->… => -3r6c2 => r5c4=9
(-7r5c2)->7r5c1->2r4c1->8r4c2->8r2c3->7r8c3->7r1c8->... => -7r1c2 => r1c2=2
(-8r5c9)->8r5c6->4r8c6->4r1c5->5r1c9->5r9c8->4r9c9->… => -4r5c9 => -4r9c8
(-8r5c9)->8r5c6->4r8c6->(4r9c9 et 6r7c6)->6r6c9->… => -8r6c9 => r5c9=8
(-2r6c89)->28r6c56->3r4c4->(2r7c4 et 4r5c6->4r8c7)->2r8c8->... -2r45c8 => r6c6=8 + 2 placements
(-5r1c9)->4r1c9->4r9c5->9r7c5->8r8c5->7r8c3->7r1c8->… => -5r1c8 => r1c8=7 + 5 placements and a few eliminations
(-9r7c1)->8r7c1->7r8c3->3r8c1->2r4c1->4r4c4->4r1c5->9r9c5->... => -9r7c5 => r7c5=8, end by basic techniques
Robert

[DEFISE]

By hand, mine below is not optimized in terms of number of steps, but it has the particularity that at no time does it call on the invalidity of the chains.

Hi Robert,
Good exercise, it is the logic of AIC but with "persistence" (= memorization) and without systematic continuity in the chains.