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 Killer Sudoku 24 August 2019 
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Posted on: Sat Aug 24, 2019 11:19 pm




Posts: 567
Location: Dublin, Ireland
Joined: Tue Mar 01, 2016 10:03 pm
Post Killer Sudoku 24 August 2019
I really struggled with today's Killer Sudoku. I finally got it finished a couple of minutes ago, but I was concerned that my year to date streak was going to come to an end. I find that Saturday's difficult Killer is often as difficult as, if not more difficult than, Friday's.


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Posted on: Sun Aug 25, 2019 8:14 am




Posts: 64
Joined: Sun Jan 31, 2016 7:52 am
Post Re: Killer Sudoku 24 August 2019
I thought it was very easy for a Friday Killer Sudoku. It had a high difficulty rating, but the steps required to solve the puzzle are not complicated.
I will list my method for solving the puzzle soon.


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Posted on: Sun Aug 25, 2019 8:41 am




Posts: 64
Joined: Sun Jan 31, 2016 7:52 am
Post Re: Killer Sudoku 24 August 2019
Oops, I got my dates mixed up, and I didn't read your post properly. [blush]
Friday's Killer was very easy, I haven't done Saturday's, I will have a look at it now.


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Posted on: Sun Aug 25, 2019 11:36 am




Posts: 567
Location: Dublin, Ireland
Joined: Tue Mar 01, 2016 10:03 pm
Post Re: Killer Sudoku 24 August 2019
I agree that Friday's difficult Killer was easier than usual. I see that Saturday's Killer has been solved fewer than 150 times, which is a lot lower than average. And I think this includes some people who submitted the puzzle since the solution was printed.

Patrick, would it be possible to set the counter for number of times solved so that it freezes once the time limit for submitting for points has been passed?


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Posted on: Sun Aug 25, 2019 12:38 pm




Posts: 64
Joined: Sun Jan 31, 2016 7:52 am
Post Re: Killer Sudoku 24 August 2019
Here is my method for solving the 24/8 Killer Sudoku, (I use box to refer to any of the 3 by 3 cell areas that make up the puzzle)

1. add cages in box a7-c9 >> c7=8

2. add cages in box c7-f9 >> f7=2

3. add cages in box g7-i9 >> h7=7

4. add cages in box g1-i3 >> g3=8

5. f9=7 (only cell in row 9 that can be 7)

6. paired cells f2,f3 (1,4)

7. d6 or d7 must be 1

8. f3 not 3 (refer to cages e1 & f5)

9. f3 not 6 (refer cage f5) >> f4=5

10. a6 & b6 = 4,8 (only cells in row 6 with 4 & 8) >> a5=6

11. add cages in box a1-c3 (a3+c3=d1+5) >> d2=2,3,5

12. b2,b3 = 1,7 (only cells in box that can be 1)

13. paired cells b2,b3 (1,7)

The puzzle can now be solved with basic steps.


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Posted on: Sun Aug 25, 2019 12:47 pm




Posts: 64
Joined: Sun Jan 31, 2016 7:52 am
Post Re: Killer Sudoku 24 August 2019
For comparison, here are the steps required to solve the Friday 23/8 Killer Sudoku:

1. Add cages in box a1-c3 >> c1=5,6 b3=8,9 >> d1 & d2=1,2,3

2. Add cages in columns 1-4 >> e8 & e9=4,5,6,7,8,9

3. Add cages in box d7-f9 >> e7 & f9=1,3

4. d7,d8 or d9 must be 2 (no other cells in that box can be 2) >> d1 & d2=1,3 >> c1=5 >> b3=9

5. cage a2 (13)=6,7

6. Add cages in box a7-c9 >> a7=5,8 c7=1,4

Now we have 3 cells solved and pencil marks in only 10 other cells. The puzzle can now be solved with easy steps.


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Posted on: Sun Aug 25, 2019 1:06 pm




Posts: 2597
Joined: Thu May 12, 2011 11:58 pm
Post Re: Killer Sudoku 24 August 2019
Thanks, I'll compare these steps to what my solver says about the puzzles.

For reference, the Friday (easier) puzzle:

Image

and the Saturday (harder) one:

Image


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Posted on: Mon Aug 26, 2019 10:20 am




Posts: 215
Joined: Thu May 12, 2011 11:51 pm
Post Re: Killer Sudoku 24 August 2019
I agree that this Friday was unusually easy and this Saturday was unusually difficult. I didn't have time to see Saturday through to completion.


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