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 Difficult 7x7 22 August 22 
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Posted on: Tue Aug 23, 2022 12:03 am




Posts: 956
Location: Ukraine
Joined: Tue Mar 01, 2016 10:03 pm
Post Difficult 7x7 22 August 22
I found the above puzzle incredibly difficult. Having made several attempts and having gotten stuck each time, I made one last attempt with a few minutes to go to midnight CET. I was very relieved to find it coming together at long last and I solved it with 44 seconds to spare! [woot]

Whew!


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Posted on: Tue Aug 23, 2022 12:24 am




Posts: 135
Joined: Tue Apr 24, 2012 7:47 pm
Post Re: Difficult 7x7 22 August 22
Congrats, paulv66! That 7*7 was TOO hard for me, so I threw in the towel. I remember Patrick kicking around the idea of having a "down to the wire" achievement. Just 44 seconds to go would be an awesome way to earn it.

skeeter84


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Posted on: Tue Aug 23, 2022 1:04 am




Posts: 3296
Joined: Thu May 12, 2011 11:58 pm
Post Re: Difficult 7x7 22 August 22
skeeter84 wrote:
Congrats, paulv66! That 7*7 was TOO hard for me, so I threw in the towel. I remember Patrick kicking around the idea of having a "down to the wire" achievement. Just 44 seconds to go would be an awesome way to earn it.

skeeter84


Congrats on getting it [thumbup]

Not sure how I'd detect a "down to the wire" achievement: could you start a puzzle at any time,
solve it but not fill in the final number, and then submit it with only a few seconds left?


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Posted on: Tue Aug 23, 2022 1:09 am




Posts: 691
Joined: Wed Apr 16, 2014 9:20 pm
Post Re: Difficult 7x7 22 August 22
I agree. It was tough. The puzzles that do this to me surprise me, now.
It took me several attempts with T & E to get it. My first choice of where to start the T & E didnt work out. I needed to try a different option.

These are the puzzles that make me anxious. I know I am struggling. I NEED to get the dailies done.
I also need to calm down. I have to leave this puzzle, for now. (That is painful for me.)

I do the following:
a) Finish ALL the other dailies, maybe even the EXTRA but the EXTRA can always wait.

Doing the EXTRA depends on time remaining before the clock resets, the ease of the EXTRA, and my anxiety level (Am I calmer?, Can I revisit that challenging puzzle?).

b) Return to the challenging puzzle. Look for a 2nd option to use T & E. Work it through. You may to find a 3rd option, or redo the puzzle from the beginning. That method always worries me due to time, but sometimes it is the best method.

If you need to redo the puzzle: Be savage with your assumptions. Why did you make this choice? Are you sure, you know there is an issue with the puzzle, could you have been wrong?

Double check your assumptions. I usually find that is where the error occurred.


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Posted on: Tue Aug 23, 2022 2:52 am




Posts: 275
Joined: Thu May 12, 2011 11:51 pm
Post Re: Difficult 7x7 22 August 22
Ditto. I didn't have.time to do more than give up on this one.


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Posted on: Tue Aug 23, 2022 4:44 am




Posts: 135
Joined: Tue Apr 24, 2012 7:47 pm
Post Re: Difficult 7x7 22 August 22
Hi, Patrick. As for the "down to the wire" achievement I mentioned in my previous post, yes, you could start solving a given puzzle at any time, but you'd need to finish it within the very final minute of it still being worth any points. As an example, let's consider today's patterned 9*9 puzzle. We've got 2 days to get the job done - all of the 22nd and all of the 23rd. If anybody were to submit the final solution on August 24th, he/she would not earn any points. For the patterned 9*9, you could submit your final solution between 23:59:00 Central European Time and whenever the next calendar day comes up. Imagine that I were to submit a solution at 23:59:30 on August 23rd, 2022 and the new batch of puzzles came up at 00:00:15 CET on August 24th. As such, I'd have 45 seconds to spare and I'd still be within the very final minute of being able to earn any points for the puzzle. As always, the decision to ultimately create such an achievement (or not) is yours and yours alone. If you DO decide to implement it at some point in the future, please don't feel pressured in any way, shape or form. Thanks for your consideration, Patrick, and have a great day.

skeeter84


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Posted on: Tue Aug 23, 2022 8:08 am




Posts: 57
Joined: Sun Feb 03, 2013 3:25 am
Post Re: Difficult 7x7 22 August 22
Yep, quite hard one. The solution has already been released, so I can offer my solving path (after settling the ‘^’ cages and without mentioning obvious candidates/singles):

1) rule of parity: F6 = 46; E6 = 246
2) D7 ≠ 2 (due to a conflict with FG6)
3) 17+ cage can only be 737 or 746
4) AB1 ≠ 74 (due to D1 = 47) nor ≠ 36 (→ CG2 both = 6)
5) crucial (in my opinion) hi/lo decision on F6: if F6 = 4 → A6 = 2 → A5 can be 3 or 7…
a) if 3 → AB1 = 14; A2 = 7 → no possible combination for the A2 cage
b) if 7 → AB1 = 14; A2 = 3 and B23 must contain 7 (due to two 7’s in rows 4 and 5), which gives together another 4 for col. B
→ → → F6 ≠ 4 = 6
6) 17+ cage ≠ 737 (otherwise two 5’s in CD6) = 746
7) hidden triple (123) in AEF1 → E2 = 12345
8) 7 in col. E must be in E45 → E45 = 67
9) X-wing on 7 in EF45 → A5 ≠ 7 nor A2 ≠ 7 (due to the 7 forced into B23), thus A6 = 7
10) rule of parity: A3 = 6
11) three 6’s in rows 1, 2 and 3 → B23 can only be 457
12) hidden pair (36) in B45; the rest is easy.

EDIT: Steps 6) and 7) can be ignored by using an argument that if the E1 cage contains 7, then a sum of all four top cages (even if AB1 = only 1–4) would be 47, which would force a sum of 19 into CEG2 – impossible (max. 18) → 7 in col. E must be in E45. Etc…


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