SudokuSolver Forum

A forum for Sudoku enthusiasts to share puzzles, techniques and software
It is currently Mon Apr 29, 2024 11:50 am

All times are UTC




Post new topic Reply to topic  [ 2 posts ] 
Author Message
 Post subject: Pinata Killer Sudoku 37
PostPosted: Sun Jun 09, 2013 8:45 am 
Offline
Expert
Expert

Joined: Sat Jul 28, 2012 11:05 pm
Posts: 92
Pinata Killer Sudoku 36 Solution:
Image
Pinata Killer Sudoku 37
Image

Jsudoku Code: 3x3::k:6400:3841:3841:5378:7427:7427:7427:7427:7427:6400:6400:5378:5378:5378:4100:7427:7427:2565:6400:6400:5378:3334:3334:4100:4100:4103:2565:6400:4104:4104:4104:4361:7434:7434:4103:4103:3083:3083:2060:2060:4361:7434:7434:3597:3597:8718:4367:4367:4367:4361:7434:7434:1808:1808:8718:8718:5649:2834:2834:3091:3091:1808:3604:8718:8718:5649:5649:5649:3091:10773:10773:3604:8718:1302:1302:5649:10773:10773:10773:10773:10773:

Sudoku Solver Score: 1.25


Last edited by Pinata on Tue Jul 23, 2013 10:20 am, edited 1 time in total.

Top
 Profile  
Reply with quote  
PostPosted: Mon Jun 10, 2013 8:13 pm 
Offline
Grand Master
Grand Master

Joined: Wed Apr 23, 2008 6:04 pm
Posts: 1895
Location: Lethbridge, Alberta, Canada
Thanks Pinata for your latest killer.

An easier one this time. The steps kept flowing, except for a short pause for thought before I spotted steps 13 and 14.

Here is my walkthrough for Pinata Killer 37:
Prelims

a) R1C23 = {69/78}
b) R23C9 = {19/28/37/46}, no 5
c) R3C45 = {49/58/67}, no 1,2,3
d) R5C12 = {39/48/57}, no 1,2,6
e) R5C34 = {17/26/35}, no 4,8,9
f) R5C89 = {59/68}
g) R7C45 = {29/38/47/56}, no 1
h) R78C9 = {59/68}
i) R9C23 = {14/23}
j) 7(3) cage at R6C8 = {124}
k) 29(7) cage at R1C5 = {1234568}, no 7,9
l) 42(7) cage at R8C7 = {3456789}, no 1,2

1. Naked triple {124} in 7(3) cage at R6C8, CPE no 1,2,4 in R4C8
1a. R7C78 = {12} (hidden pair in N9), locked for R7, clean-up: no 9 in R7C45
1b. Naked triple {124} in 7(3) cage at R6C8, 4 locked for R6 and N6
1c. 45 rule on N9 2 outies R9C56 = 14 = {59/68}
1d. R7C45 = {38/47} (cannot be {56} which clashes with R9C56), no 5,6 in R7C45

2. R5C89 + R78C9 form naked quad {5689} (because R5C89 and R78C9 cannot have the same combinations), CPE no 5,6,8,9 in R4C9

3. 45 rule on R123 1 innie R3C8 = 1 outie R4C1 + 6, R3C8 = {789}, R4C1 = {123}
3a. 45 rule on R123 3 outies R4C189 = 10 = {127/136/235}, no 8,9
3b. 1,2 of {127} must be in R4C19 -> no 7 in R4C8
3c. 5,6,7 only in R4C8 -> R4C8 = {567}

4. 45 rule on R1234 3 innies R4C567 = 19 = {289/379/469/478/568}, no 1

5. 45 rule on R5 3 innies R5C567 = 11 = {128/137/146/236/245}, no 9

6. 45 rule on R789 1 outie R6C1 = 1 innie R7C8 + 5, R7C8 = {12} -> R6C1 = {67}

7. 45 rule on N1 2 innies R23C3 = 1 outie R4C1 + 5
7a. Max R4C1 = 3 -> max R23C3 = 8, no 8,9 in R23C3

8. 45 rule on N7 2 innies R78C3 = 1 outie R6C1 + 6
8a. Min R6C1 = 6 -> min R78C3, no 1,2 in R8C3

9. 45 rule on N7 4(1+3) outies R6C1 + R8C45 + R9C4 = 16
9a. Min R6C1 = 6 -> max R8C45 + R9C4 = 10, no 8,9 in R8C45 + R9C4

10. 12(3) cage at R7C6 = {129/138/147/246} (cannot be {156} which clashes with R9C56, cannot be {237} which clashes with R7C45, cannot be {345} because R7C7 only contains 1,2), no 5
10a. 9 of {129} must be in R7C6 -> no 9 in R8C6

[Step 11 may not have been necessary, if I’d spotted steps 13 and 14 earlier, but it contains obvious steps so I’ve kept it in.]
11. 9 in R5 only in R5C12 = {39} or in R5C89 = {59} -> R5C12 = {39/48} (cannot be {57}, locking-out cages), no 5,7 in R5C12
11a. Killer pair 8,9 in R5C12 and R5C89, locked for R5
11b. 9 in R5 only in R5C12 = {39} or in R5C89 = {59} -> R5C34 = {17/26} (cannot be {35}, locking-out cages), no 3,5 in R5C34
11c. R5C567 (step 5) = {137/236/245} (cannot be {146} which clashes with R5C34)

12. 45 rule on C6789 2 outies R19C5 = 9 = [18/36/45], clean-up: no 5 in R9C6 (step 1c)
12a. 9 in N8 only in R78C6, locked for C6

[With hindsight I ought to have looked at the combinations for the large cages in C12 earlier.]
13. 25(6) cage at R1C1 = {123469/123478} (cannot be {123568/124567} which clash with R1C23), no 5, 4 locked for N1
13a. Killer pair 6,7 in 25(5) cage and R1C23, locked for N1
13b. 5 in N1 only in R23C3, locked for C3 and 21(5) cage at R4C1, no 5 in R1C4 + R2C45

14. 34(6) cage at R6C1 = {145789/235789} (cannot be {136789/245689/345679} which clash with R9C23), no 6 -> R6C1 = 7, R7C8 = 2 (step 6), R7C7 = 1, clean-up: no 1 in R5C4
14a. R78C3 = {67} (hidden pair in N7), locked for C3 and 22(5) cage at R7C3, no 6,7 in R8C45 + R9C4, clean-up: no 8,9 in R1C2, no 2 in R5C4
14b. R78C3 = {67} = 13 -> R8C45 + R9C4 = 9 = {135/234}, 3 locked for N8, clean-up: no 8 in R7C45
14c. Naked pair {47} in R7C45, locked for R7 and N8 -> R78C3 = [67], R8C45 + R9C4 = {135}, locked for N8, clean-up: no 4 in R1C5 (step 12), no 9 in R9C6 (step 1c)
14d. Naked pair {68} in R9C56, locked for N8 and 42(7) cage at R8C7 -> R78C6 = [92]

15. R78C9 = {68} (hidden pair in N9) -> R7C9 = 8, R8C9 = 6, clean-up: no 2,4 in R23C9, no 6,8 in R5C8
15a. Naked pair {59} in R5C89, locked for R5 and N6, clean-up: no 3 in R5C12
15b. Naked pair {48} in R5C12, locked for R5 and N4
15c. Naked pair {14} in R6C89, locked for R6 and N6

16. Naked pair {35} in R7C12, locked for N7, clean-up: no 2 in R9C23
16a. Naked pair {14} in R9C23, locked for R9 and N7
16b. Naked pair {89} in R8C12, locked for R8 and N7 -> R9C1 = 2

17. R1C3 = 8 (hidden single in C3), R1C2 = 7
17a. 25(6) cage at R1C1 (step 13) = {123469} (only remaining combination), 2 locked for C2 and N1

18. R4C189 (step 3a) = {127/136} -> R4C1 = 1, R3C8 = 7 (step 3), R4C8 = 6, R4C9 = 3, R5C3 = 2, R5C7 = 7, R5C4 = 6, R4C3 = 9, R4C2 = 5, R4C4 = 2 (cage sum), R6C23 = [63], R6C4 = 8 (cage sum)
18a. R4C67 = [48], R6C67 = [52], R46C5 = [79], R5C5 = 1 (cage sum), R5C6 = 3, R1C5 = 3, R9C5 = 6 (step 12), R9C6 = 8, R8C5 = 5, R89C4 = [13], R7C45 = [74], R3C5 = 8, R3C4 = 5

19. Naked pair {19} in R23C9, locked for C9 and N3 -> R5C89 = [95], NS R6C89 = [14]

and the rest is naked singles.

Rating Comment:
I'll rate my walkthrough for Pinata #37 at Easy 1.25, ignoring step 11 which with hindsight probably wasn't necessary. Even with step 11 my rating would only have been 1.25; the locking-out cages steps are easy and obvious ones.


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: No registered users and 124 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:  
Powered by phpBB® Forum Software © phpBB Group