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 Post subject: Pinata Killer Sudoku 49
PostPosted: Tue Jan 21, 2014 12:02 am 
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Joined: Sat Jul 28, 2012 11:05 pm
Posts: 92
Pinata Killer Sudoku 48 Solution:
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Pinata Killer Sudoku 49
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Jsudoku Code: 3x3::k:2304:2304:4353:4353:7170:4099:4612:4612:4612:2304:6405:6405:6405:7170:4099:4099:7174:7174:4103:6405:4104:4104:7170:7170:4099:4099:7174:4103:6405:4104:10249:10249:7170:7170:7170:7174:4103:2314:2314:10249:10249:10249:1803:1803:4108:5389:9742:9742:9742:10249:10249:3087:7440:4108:5389:6417:6417:9742:9742:3087:3087:7440:4108:5389:5389:6417:6417:9742:7440:7440:7440:2578:3603:3603:3603:6417:9742:2836:2836:2578:2578:

Sudoku Solver Score: 1.45


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PostPosted: Tue Jan 21, 2014 9:21 pm 
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Joined: Mon Apr 21, 2008 9:44 am
Posts: 310
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Despite SudokuSolver's score this one can be solved quite easily and fast. Thanks for this fun killer, Pinata!

Pinata 49 Walkthrough:
1. R123
a) 17(2) = {89} locked for R1
b) 18(3) = {567} locked for R1+N3
c) 28(4) = {4789} since 5,6 only possible @ R4C9 -> R4C9 = 7; 4 locked for N3
d) 16(5) = {12346} -> R2C6 = 6, R1C6 = 4
e) 28(7) = {1234567} -> R4C78 = {46} locked for R4+N6
f) 8,9 locked in R123C4 @ N2 for C4

2. C456 !
a) R6C4 <> 4 since it sees all 4 of C5
b) Innies N5 = 5(2) = {23} locked for N5
c) ! Hidden Killer pair (23) in 38(7) @ C5 since R123C5 @ 28(7) can only have one (23) because of R4C6 = (23)
d) 38(7) = {2345789} because of Hidden Killer pair (23) in C5 + R6C4 = (23); R6C23+R7C4 <> 2,3
e) Using R4C78 = (46): Outies N69 = 12(3) = 1{29/38} since {237} blocked by Killer pair (23) of 38(7) @ C5 -> 1 locked for C6+N8

3. C789 !
a) 7(2) = {25} locked for R5+N6
b) 16(3) = {169/358} since R56 = (1389) and {349} blocked by R23C9 = (489) -> R7C9 = (56)
c) Naked pair (56) locked in R17C9 for C9
d) 2 locked in 10(3) @ C9 for N9 -> 10(3) = 2{17/35}; R9C8 = (57)
e) ! Hidden Killer pair (13) in R3C8 + 29(5) for C8 since 29(5) can only have one of (13) -> R3C8 = (13); R8C67 <> 1,3
f) Hidden Single: R7C6 = 1 @ N8
g) 12(3) = {138} -> 3,8 locked for C7
h) 16(3) = {169} since {358} is blocked by R6C6 = (38) -> R7C9 = 6; 1,9 locked for C1+N6
i) 11(2) = {29} -> R9C7 = 9, R9C6 = 2
j) R9C9 = 3, R8C9 = 2 -> R9C8 = 5
k) Outie N69 = R8C6 = 9

4. C123
a) 14(3) = {167} locked for R9+N7
b) Hidden Single: R8C4 = 6 @ N8
c) R9C4 = 4
d) Outie N7 = R6C1 = 5
e) 9(3) = {234} -> R2C1 = 4; 2,3 locked for R1+N1
f) 21(4) = {3459} -> R8C1 = 3, R8C2 = 4, R7C1 = 9
g) 38(7) = {2345789} -> R6C2 = 9, R6C3 = 4
h) R2C9 = 8, R2C8 = 9, R4C6 = 3
i) Hidden Single: R5C3 = 3 @ C3 -> R5C2 = 6
j) 25(5) @ N1 = {23578} -> R2C4 = 3, R4C2 = 2, R3C2 = 8; 5,7 locked for R2+N1

5. Rest is singles.

Rating:
Hard 1.0. I used two Hidden Killer pairs.


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PostPosted: Wed Jan 22, 2014 6:42 pm 
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Joined: Wed Apr 23, 2008 6:04 pm
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Location: Lethbridge, Alberta, Canada
I agree completely with Afmob's comments. It didn't take me long to solve this killer.

Afmob's solving path was quicker than mine:
partly because of step 2a), a nice CPE which I didn't spot. We both used hidden killer pairs, but at least one of them was different.

Here is my walkthrough for Pinata Killer #49:
Prelims

a) R1C34 = {89}
b) R5C23 = {18/27/36/45}, no 9
c) R5C78 = {16/25/34}, no 7,8,9
d) R9C67 = {29/38/47/56}, no 1
e) 9(3) cage at R1C1 = {126/135/234}, no 7,8,9
f) 10(3) cage at R8C1 = {127/136/145/235}, no 8,9
g) 28(4) cage at R2C8 = {4789/5689}, no 1,2,3
h) 16(5) cage at R1C6 = {12346}
i) 28(7) cage at R1C5 = {1234567}, no 8,9

1. Naked pair {89} in R1C34, locked for R1
1a. 8,9 in N3 only in R2C89 + R3C9, locked for 28(4) cage at R2C8, no 8,9 in R4C9
1b. 8,9 in N2 only in R123C4, locked for C4

2. 45 rule on N3 1 outie R4C9 = 3 innies R2C7 + R3C78 + 1, min R2C7 + R3C78 = 6, max R4C9 = 7 -> R2C7 + R3C78 = 6 = {123}, locked for N3 and 16(5) cage at R1C6, R4C9 = 7
2a. R4C9 = 7 -> 28(4) cage at R2C8 = {4789}, 4 locked for N3
2b. Naked triple {567} in 18(3) cage at R1C7, locked for R1 -> R12C6 = [46], clean-up: no 5,7 in R9C7

3. 28(7) cage at R1C5 = {1234567}, 7 locked for N2, R4C78 = {46}, locked for R4 and N6, clean-up: no 1,3 in R5C78
3a. Naked pair {25} in R5C78, locked for R5 and N6, clean-up: no 4,7 in R5C23

4. 9(3) cage at R1C1 = {135/234}
4a. 4,5 only in R2C1 -> R2C1 = {45}
4b. 3 only in R1C12, locked for R1 and N1

5. 16(3) cage at R5C9 = {169/358} (cannot be {259/268} because 2,5,6 only in R7C9, cannot be {349} which clashes with 28(4) cage at R2C8, ALS block)
5a. 5,6 only in R7C9 -> R7C9 = {56}
5b. Naked pair {56} in R17C9, locked for C9

6. 2 in C9 only in R89C9, locked for N9, clean-up: no 9 in R9C6
6a. 10(3) cage at R8C9 contains 2 = {127/235}, no 4,6
6b. 5,7 in R9C8 only in R9C8 -> R9C8 = {57}
6c. 4 in C9 only in R23C9, locked for N3

7. 45 rule on N5 2 innies R4C6 + R6C4 = 5 = [14]/{23}
7a. 28(7) cage at R1C5 = {1234567}, 5 locked for N2

8. 45 rule on N69 (using R4C78 = {46} = 10) 3 outies R789C6 = 12 = {129/138/237}, no 5, clean-up: no 6 in R9C7
8a. Killer triple 1,2,3 in R4C6 and R789C6, locked for C6

9. 28(7) cage at R1C5 = {1234567}, CPE no 1,2,3 in R456C5

10. 45 rule on R1234 2 innies R4C45 = 1 outie R5C1 + 7
10a. Max R4C45 = 14 -> max R5C1 = 7

11. 45 rule on R6789 2 innies R6C56 = 1 outie R5C9 + 4
11a. Min R6C56 = 9 -> no 1,3 in R5C9
11b. 16(3) cage at R5C9 (step 5) = {169/358}
11c. 1,3 only in R6C9 -> R6C9 = {13}
11d. 1,3 in N6 only in R6C789, locked for R6, clean-up: no 2 in R4C6 (step 7)
11e. 28(7) cage at R1C5 = {1234567}, 2 locked for C5 and N2

12. 2 in C6 only in R789C6, locked for N8
12a. R789C6 (step 8) = {129/237}, no 8, clean-up: no 3 in R9C7
12b. 8 in N8 only in R789C5, locked for C5 and 38(7) cage at R6C2, no 8 in R6C23
12c. 38(7) cage = {1256789/1346789/2345789}, CPE no 9 in R6C5

13. Hidden killer pair 1,3 in R123C5 + R4C6 for 28(7) cage at R1C5, R4C6 = {13} -> R123C5 must contain one of 1,3
13a. Hidden killer pair 1,3 in R123C5 and R789C5 for C5, R123C5 contains one of 1,3 -> R789C5 must contain one of 1,3
13b. Killer pair 1,3 in R789C5 and R789C6, locked for N8
13c. 38(7) cage at R6C2 = {1256789/2345789} (cannot be {1346789} because R789C5 only contains one of 1,3), 2 locked for R6

14. 45 rule on N7 3(1+2) outies R6C1 + R89C4 = 15
14a. Min R89C4 = 9 -> max R6C1 = 6
14b. R6C1 + R89C4 = 4{47}/4{56}/5{46}/6{45}, CPE no 4 in R6C4
14c. R6C4 = 2 -> R4C6 = 3 (step 7)

15. R789C6 (step 12a) = {129} (only remaining combination) -> R9C6 = 2, R78C6 = {19}, locked for C6 and N8, R9C7 = 9

16. R8C9 = 2 (hidden single in N9)
16a. 45 rule on R9 2 remaining innies R9C45 = 12 = [48] (cannot be {57} which clashes with R9C8)

17. 38(7) cage at R6C2 (step 13c) = {2345789} (only remaining combination) -> R6C23 = {49}, locked for R6 and N4

18. R5C59 = [49] (hidden pair in R5)
18a. R5C9 = 9 -> R67C9 = 7 = [16], R9C9 = 3, R9C8 = 5 (cage sum)

19. R6C1 + R89C4 = 15 (step 14)
19a. R8C4 = 6 (hidden single in N8), R9C4 = 4 -> R6C1 = 5, R2C1 = 4 -> R1C12 = 5 = {23}, locked for R1 and N1, R1C5 = 1

20. R5C1 = 7 (hidden single in N4) -> R34C1 = 9 = {18} (only possible combination), locked for C1, R9C1 = 6

21. Naked pair {17} in R9C23, locked for N7
21a. R6C1 = 5 -> 21(4) cage at R6C1 = {3459} (only possible combination), R8C2 = 4, R78C1 = {39}, locked for C1 and N7, R1C12 = [23], R5C23 = [63] (hidden pair in N4), R6C23 = [94]

22. R3C34 = [69] (hidden pair in R3), R4C3 = 1 (cage sum)

and the rest is naked singles.

Rating Comment:
I'll rate my walkthrough for Pinata #49 at Hard 1.0. I used a couple of hidden killer pairs and CPEs.

I don't understand the SS score. I don't think I used any steps which Sudoku Solver wouldn't be able to find.


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