.
SER = 7.3
- Code: Select all
Resolution state after Singles (and whips[1]):
+-------------------+-------------------+-------------------+
! 5789 1279 15789 ! 16789 4 1568 ! 12689 3 128 !
! 4789 12479 1789 ! 3 16789 168 ! 5 24689 1248 !
! 34589 1349 6 ! 189 1589 2 ! 1489 489 7 !
+-------------------+-------------------+-------------------+
! 39 8 2 ! 1469 1569 7 ! 146 456 1345 !
! 6 5 37 ! 1248 128 1348 ! 12478 2478 9 !
! 1 379 4 ! 2689 25689 3568 ! 2678 25678 2358 !
+-------------------+-------------------+-------------------+
! 45789 4679 5789 ! 24678 3 468 ! 24789 1 2458 !
! 2 1347 13578 ! 1478 178 9 ! 478 4578 6 !
! 4789 14679 1789 ! 5 12678 1468 ! 3 24789 248 !
+-------------------+-------------------+-------------------+
237 candidates
The puzzle is not only in W5 but also in the much simpler BC5. Having an sk-loop in a puzzle with so low SER, as in pjb's solution is fun, but as also noticed by pjb, it doesn't simplify the solution.
There is indeed at least one
2-step solution in BC5. This is one case where there is no need to increase the length or complexity of individual chains in order to get a shorter path than provided by the simplest-first strategy.
biv-chain[4]: c6n5{r6 r1} - r3n5{c5 c1} - c1n3{r3 r4} - b6n3{r4c9 r6c9} ==> r6c9≠5, r6c6≠3singles ==> r5c6=3, r5c3=7, r8c3=3, r8c8=5, r4c9=5, r6c9=3, r6c2=9, r4c1=3, r3c2=3
whip[1]: b6n1{r5c7 .} ==> r1c7≠1, r3c7≠1
whip[1]: r3n1{c5 .} ==> r1c4≠1, r1c6≠1, r2c5≠1, r2c6≠1
singles ==> r9c6=1, r8c2=1, r7c6=4, r8c7=4, r2c9=4, r3c1=4, r3c5=5, r6c6=5, r3c4=1, r9c2=4, r7c2=6, r9c5=6, r7c4=2, r7c9=8, r9c9=2, r1c9=1, r2c3=1
whip[1]: b5n6{r6c4 .} ==> r1c4≠6
whip[1]: b7n7{r9c1 .} ==> r1c1≠7, r2c1≠7
whip[1]: r3n8{c8 .} ==> r1c7≠8, r2c8≠8
whip[1]: r3n9{c8 .} ==> r1c7≠9, r2c8≠9
whip[1]: c6n8{r2 .} ==> r1c4≠8, r2c5≠8
biv-chain[5]: r1c2{n7 n2} - r1c7{n2 n6} - r4c7{n6 n1} - r4c5{n1 n9} - b2n9{r2c5 r1c4} ==> r1c4≠7stte