SudokuSolver Forum

A forum for Sudoku enthusiasts to share puzzles, techniques and software
It is currently Thu Mar 28, 2024 9:01 pm

All times are UTC




Post new topic Reply to topic  [ 2 posts ] 
Author Message
 Post subject: Assassin 65 v3 Revisit
PostPosted: Mon Aug 16, 2021 6:03 am 
Offline
Grand Master
Grand Master

Joined: Wed Apr 16, 2008 1:16 am
Posts: 1040
Location: Sydney, Australia
Attachment:
a65v3r.JPG
a65v3r.JPG [ 98.54 KiB | Viewed 3114 times ]
Assassin 65 v3 Revisit.

Our 20th Revisit thread. Time flies! Mixture of reactions to this puzzle in the archives (see hyperlink above). It gets a score of 1.75 and JSudoku uses 4 'complex intersections'.

Code: Select, Copy & Paste into solver:
3x3::k:4352:4352:4354:4099:4099:4099:2310:3591:3591:4352:3082:4354:4354:3853:2310:2310:3856:3591:3858:3082:3082:10261:3853:3095:3856:3856:5658:3858:3082:4637:10261:3853:3095:5921:5658:5658:3858:4637:4637:10261:10261:10261:5921:5921:3628:4397:4397:4637:2608:2865:10261:5921:4148:3628:4397:4663:4663:2608:2865:10261:4148:4148:3628:3903:4663:3649:3649:2865:5444:5444:4148:3143:3903:3903:3649:3147:3147:3147:5444:3143:3143:
Solution:
+-------+-------+-------+
| 5 4 9 | 6 7 3 | 1 2 8 |
| 8 1 3 | 5 9 2 | 6 7 4 |
| 7 6 2 | 4 1 8 | 3 5 9 |
+-------+-------+-------+
| 2 3 8 | 1 5 4 | 9 6 7 |
| 6 5 1 | 9 8 7 | 2 4 3 |
| 9 7 4 | 2 3 6 | 8 1 5 |
+-------+-------+-------+
| 1 9 7 | 8 2 5 | 4 3 6 |
| 4 2 5 | 3 6 9 | 7 8 1 |
| 3 8 6 | 7 4 1 | 5 9 2 |
+-------+-------+-------+
Cheers
Ed


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 18, 2021 8:23 pm 
Offline
Grand Master
Grand Master

Joined: Wed Apr 23, 2008 6:04 pm
Posts: 1893
Location: Lethbridge, Alberta, Canada
Another nice Assassin Revisit!

Actually the 21st Revisit, 20 posted by Ed, I posted one.

Getting two puzzles, new ones or revisits each month is great! They fit in nicely with everything else I do.

Note: The hyperlink leads to a spoiler, but even if used that's only the beginning of the puzzle.

I've rewritten step 2e in a much simpler form.
Here's my walkthrough for Assassin 65V3 Revisited:
Prelims

a) R34C6 = {39/48/57}, no 1,2,6
b) R67C4 = {19/28/37/46}, no 5
c) 9(3) cage at R1C7 = {126/135/235}, no 7,8,9
d) 22(3) cage at R3C9 = {589/679}
e) 11(3) cage at R6C5 = {128/137/146/2236/245}, no 9
f) 21(3) cage at R8C6 = {489/579/678}, no 1,2,3
g) 12(4) cage at R2C2 = {1236/1245}, no 7,8,9

1a. 45 rule on N69 2(1+1) outies R3C9 + R8C6 = 18 -> R3C9 = 9, R8C6 = 9, clean-up: no 3 in R34C6, no 1 in R6C4
1b. R8C6 = 9 -> R89C7 = 12 = {48/57}, no 6
1c. 45 rule on C789 2 outies R28C6 = 11 = [29]
1d. R2C6 = 2 -> R12C7 = 7 = {16/34}, no 5
1e. 45 rule on C123 2 outies R28C4 = 8 = {17/35}/[62], no 4,8,9, no 6 in R8C6
1f. 45 rule on N7 1 outie R8C4 = 1 innie R7C1 + 2 -> R8C4 = {357}, R7C1 = {135}, clean-up: no 6,7 in R2C5
1g. Max R2C4 = 5 -> min R12C3 = 12, no 1,2 in R12C3
1h. Max R7C1 = 5 -> min R6C12 = 12, no 1,2 in R6C12
1i. 40(7) cage at R3C4 must contain 9, locked for N5, clean-up: no 1 in R7C4
1j. R67C4 = {28/46} (cannot be {37} which clashes with R28C4), no 3,7
1k. 45 rule on N6 1 outie R3C9 = 3 innies R5C9 + R6C89 = 9 = {126/135/234}, no 7,8,9
1l. 45 rule on N9 1 innie R7C9 = 1 remaining outie R6C8 + 5 -> R7C9 = {678}, R6C8 = {123}
1m. 45 rule on C5 3 innies R159C5 = 19 = {289/379/469/478/568}, no 1
1n. 45 rule in R12 3 innies R2C258 = 17 = {179/359/368/458/467}
1o. 1 of {179} must be in R2C2 -> no 1 in R2C58
1p. 45 rule on C1 3 outies R169C2 = 19 = {289/379/469/478/568}, no 1

2a. 16(4) cage at R6C8 = {1249/1267/1348/1357/2356} (cannot be {1258/1456/2347} which clash with R89C7)
2b. Consider placement of 9 in N9
16(4) cage at R6C8 = {1249}, no 3
or 12(3) cage at R8C9 = {129} => 16(4) cage must contain at one of 1,2 in R6C8
-> R6C8 = {12}, clean-up: no 8 in R7C9 (step 1l)
2c. 16(4) cage at R6C8 = {1249/1348/1357/2356} (cannot be {1267} which clashes with R7C9)
2d. Killer pair 4,5 in 16(4) cage and R89C7, locked for N9
2e. Killer triple 4,6,7 in 16(4) cage, R7C9 and R89C7, locked for N9
[I saw steps 2d and 2e in that order; together they form
Killer quad 4,5,6,7 in 16(4) cage, R7C9 and R89C7, locked for N9]

2f. 12(3) cage at R8C9 = {129/138}, 1 locked for N9

3a. R5C9 + R6C89 = {126/135/234} (step 1k), R7C9 = R6C8 + 5 (step 1l)
3b. Consider placements for R6C8 = {12}
R6C8 = 1 => R7C9 = 6, R56C9 = 8 = {35}, 5 locked for N6 => R4C89 = [67] => 1,6 in C7 only in R12C7 = {16} (cannot both be in R3C7)
or R6C8 = 2, R7C9 = 7 => R89C7 = {48}, 4 locked for C7
-> R12C7 = {16}, locked for C7 and N3
and 7 in R47C9, locked for C9
[Looking at those placements slightly differently.]
3c. R6C8 = 1 => R7C9 = 6, R56C9 = {35}
or R6C8 = 2 => 16(4) cage at R6C8 (step 2c) = {2356} => R9C8 = 9 (hidden single in N9), R89C9 = 3 = {12}, locked for C9 => R56C9 = 7 = {34}
-> R56C9 = {34/35}, no 1,2,6, 3 locked for C9 and N6
3d. 12(3) cage at R8C9 (step 2f) = {129/138} -> R9C8 = {39}
3e. 14(3) cage at R1C8 = {248/257} (cannot be {347} because 3,7 only in R1C8), no 3, 2 locked for R1 and N3
3f. 23(4) cage at R4C7 = {2489} (only possible combination, cannot be {1679} because 1,6 only in R5C8, cannot be {1589} = {589}1 which clashes with R89C7, cannot be {2579/2678/4568} which clash with R4C89), locked for N6
3g. R6C8 = 1 -> R7C9 = 6
3h. Naked pair {35} in R56C9, 5 locked for C9 and N6 -> R4C89 = [67], clean-up: no 5 in R3C6, no 4 in R6C4
3i. 14(3) cage at R1C8 = {248} (cannot be {257} because 5,7 only in R1C8), 4,8 locked for N3
3j. 4 in C9 only in R12C9, locked for N3
3k. 40(7) cage at R3C4 = {1456789/2356789}, CPE no 6 in R6C4, clean-up: no 4 in R7C4
3l. Naked pair {28} in R67C4, locked for C4
3m. 40(7) cage at R3C4 = {1456789/2356789}, CPE no 8 in R4C6, clean-up: no 4 in R3C6
3n. 16(3) cage at R1C4 = {349/358/367/457} (cannot be {169} which clashes with R1C7, cannot be {178} which clashes with R3C6), no 1

4a. 40(7) cage at R3C4 = {1456789/2356789}
4b. Consider placement for 5
5 in R3C4 => R3C78 = {37}, 7 locked for R3 => R3C6 = 8
or 5 in R4C4 + R5C456 + R67C6, CPE no 5 in R4C6
-> R34C6 = [84]
4c. 4 of {1456789} only in R3C4 -> no 1 in R3C4
[Here I spotted 4 in R3C4 or 2 in R5C5 which looked useful, but not needed because …]
4d. R5C5 = 8 (only remaining position in 40(7) cage) -> R67C4 = [28]
4e. 40(7) cage at R3C4 = {1456789}, no 3 -> R3C4 = 4
4f. 16(3) cage at R1C4 (step 3n) = {367} (only remaining combination), locked for R1 and N2 -> R12C7 = [16], clean-up: no 5 in R8C4 (step 1e), no 3 in R7C1 (step 1f)
[Note that 45 rule on N14 2(1+1) outies R2C4 + R7C1 = 6 now form naked pair {15} but I didn’t need to use this.]
4g. R2C5 = 9 (hidden single in N2) -> R34C5 = 6 = {15}, locked for C5
4h. R6C5 = 3 (hidden single in N5) -> R78C5 = 8 = [26], R56C9 = [35]
4i. 17(3) cage at R1C1 = {359/458} (cannot be {179} because 1,7 only in R2C1), no 1,7, 5 locked for N1
4j. 5 in R1 only in R1C12, locked for N1

5a. 8 in N6 only in R46C7, locked for C7, clean-up: no 4 in R89C7
[With hindsight I could have got this after step 3f, at least one of 4,8 in R456C7, but I was focussing on other steps.]
5b. Naked pair {57} in R89C7, locked for C7 and N9 -> R3C7 = 3
5c. R1C5 = 7, R9C5 = 4 -> R9C46 = 8 = {17/35}
5d. Killer pair 5,7 in 12(3) cage and R9C7, locked for R9

6a. 17(3) cage at R6C1 = {48}5/{79}1, no 6
6b. 15(3) cage at R3C1 = {258/267/357} (cannot be {159} which clashes with R7C1, cannot be {168/249} which clash with 17(3) cage, cannot be {348} because no 3,4,8 in R3C1, cannot be {456} = [654] which clashes with 12(4) cage at R2C2), no 1,4,9
6c. 2 of {258} must be in R3C1, 2 of {267} must be in R4C1 -> no 2 in R5C1
6d. 8 of {258} must be in R4C1, 3 of {357} must be in R4C1 -> no 5 in R4C1
6e. 1 in C1 only in R789C1, locked for N7
6f. 1 in N1 only in R2C2 + R3C23, locked for 12(4) cage at R2C2, no 1 in R4C2

7a. R8C4 = R7C1 + 2 (step 1f) -> R7C1 + R8C4 = [13/57]
7b. 14(3) cage at R8C3 = {239/347/356} (cannot be {248} because R8C4 only contains 3,7, cannot be {257} which clashes with R7C1 + R8C4), no 8
7c. 9 of {239} must be in R9C3 -> no 2 in R9C3
7d. R8C3 = {245} (only remaining cell for 2,4,5)
7e. 18(3) cage at R7C2 = {279/378} (cannot be {459} which clashes with 14(3) cage), no 4,5
7f. 2,8 only in R8C2 -> R8C2 = {28}, R7C23 = {37/79}, 7 locked for R7 and N7
7g. 16(4) cage at R6C8 (step 2c) = {1249/1348} -> R8C8 = {28}
7g. Naked pair {28} in R8C28, locked for R8 -> R8C9 = 1
7h. 14(3) cage = {347/356}, no 9
7i. 14(3) cage = {347/356}, CPE no 3 in R8C1 + R9C46

8a. Naked pair {45} in R8C13, 5 locked for R8 and N7 -> R89C7 = [75], R8C4 = 3, R9C3 = 6 -> R8C3 = 5 (cage sum)
8b. R7C1 = 1 -> R6C12 = 16 = {79}, locked for R6 and N4
8c. R8C4 = 3 -> R2C4 = 5 (step 1e), R12C3 = 12 = [93] (cannot be {48} which clashes with R6C3)
8d. R128C1 = [584], R1C2 = 4, R2C2 = 1, R3C23 = [62] -> R4C2 = 3 (cage sum)
8e. R7C23 = [97] -> R8C2 = 2 (cage sum)

and the rest is naked singles.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2 posts ] 

All times are UTC


Who is online

Users browsing this forum: Bing [Bot] and 10 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group