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The 9 x 9 pattern that I most loathe
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Posted on: Fri Jan 24, 2020 10:47 pm

Posts: 233
Joined: Thu May 12, 2011 11:51 pm
Re: The 9 x 9 pattern that I most loathe
I found it more difficult than average but not radically so. The 74.7 difficulty rating seems odd.

Posted on: Fri Jan 24, 2020 11:33 pm

Posts: 694
Location: Dublin, Ireland
Joined: Tue Mar 01, 2016 10:03 pm
Re: The 9 x 9 pattern that I most loathe
I think a good measure of the difficulty of a puzzle is how many people manage to solve it and how this compares to other puzzles of the same type. This latter figure is distorted by whether or not the puzzle is subscriber only.

The last time the Saturday 9x9 was subscriber only was 4 weeks ago and it was solved 101 times. Today's puzzle has been solved 71 times so far, which suggests that fewer people in total will solve it than last time around. To access whether this is significant or not, I think a few more data points would be helpful!

Posted on: Wed Sep 02, 2020 2:20 am

Posts: 694
Location: Dublin, Ireland
Joined: Tue Mar 01, 2016 10:03 pm
Re: The 9 x 9 pattern that I most loathe
Yesterday’s puzzle was quite a struggle for me until I figured out that a section of the puzzle had fairly limited options and that allowed me to get my hooks into it. I note that it has been solved relatively few times, demonstrating yet again that this particular pattern is that bit more difficult than the normal Tuesday 9x9.

While Patrick will no doubt have access to more accurate statistics, my perception is that, while the normal pattern in general is solved somewhere between 200 and 250 times (or thereabouts), this more difficult pattern is only solved around 100 times on average.

Posted on: Wed Sep 02, 2020 9:38 am

Posts: 2723
Joined: Thu May 12, 2011 11:58 pm
Re: The 9 x 9 pattern that I most loathe
For reference, here's the actual puzzle:

Posted on: Wed Sep 02, 2020 12:40 pm

Posts: 103
Joined: Sun Jan 31, 2016 7:52 am
Re: The 9 x 9 pattern that I most loathe
The cage pattern in this puzzle makes it pretty difficult. It looks like adding cages is not going to be much help, but it is the key to solving the puzzle. Don't be put off by cages with subtraction or multiplication, a lot of progress can be made if you put in the extra effort.

Posted on: Wed Sep 02, 2020 12:44 pm

Posts: 788
Joined: Fri May 13, 2011 6:51 pm
Re: The 9 x 9 pattern that I most loathe
paulv66 wrote:
I think a good measure of the difficulty of a puzzle is how many people manage to solve it and how this compares to other puzzles of the same type. ..

The subject of the difficulty level of a puzzle has been largely discussed in the past. It seems that it's a pending problem, it looks that the method of evaluation used is not very precise. Recently, it has been discussed a lot about the level of the KS's, which ones are more difficult, fridays'?, saturday's?, making comparison with previous weeks, etc., and finding many paradoxical situations.

A paradoxical example: KS of Friday's Aug 28, difficulty 196,3 solvers 305.
Yesterday's Tuesday Sep 01, difficulty 124,5 solvers 85 till the moment.
No one was limited to subscribers only.

IIRC. I expressed my opinion in the past that the best way to measure the difficulty of a puzzle is simply to relate it to the time spent by the Patrick's software in finding a unique solution.
More time, more difficulty, and vice versa, in this way puzzles of all sizes can be compared among them.

Actually I do not really know if the difficulty level (and, as a consequence, the number of stars assigned to any puzzle) is calculated considering the size, that is, related to the size of that particular puzzle, or not, etc.

In fact, I have lost the interest in this "parameter". But it's true, in the other hand, that I frequently observe (mainly with the more difficult puzzles) the number of solvers, only in real time, when I start solving the puzzle, of course that is a subjective appreciation, in order to have an idea of how much time I will need to find the solution, based on my particular experience (it's clear that the number of solvers will depend on the time of the day you look since, obviously, the number of solvers is constantly increasing along the day ).

Posted on: Wed Sep 02, 2020 4:11 pm

Posts: 2
Joined: Fri May 29, 2020 10:31 pm
Re: The 9 x 9 pattern that I most loathe
What is the trick to solving puzzles like this? I have had limited success with Tuesday 9x9 puzzles. I can pretty quickly find the handful of cells where there are only 2 or 3 possibilities but the majority of the cells have 6 or 7 possibilities and there are some where I can't eliminate any of the numbers at all. When most of the cells have 6 or more possibilities it is near impossible to start eliminating numbers that don't work and I lose interest pretty quickly.

Posted on: Wed Sep 02, 2020 4:46 pm

Posts: 694
Location: Dublin, Ireland
Joined: Tue Mar 01, 2016 10:03 pm
Re: The 9 x 9 pattern that I most loathe
prairieboy73 wrote:
What is the trick to solving puzzles like this? I have had limited success with Tuesday 9x9 puzzles. I can pretty quickly find the handful of cells where there are only 2 or 3 possibilities but the majority of the cells have 6 or 7 possibilities and there are some where I can't eliminate any of the numbers at all. When most of the cells have 6 or more possibilities it is near impossible to start eliminating numbers that don't work and I lose interest pretty quickly.

For the Tuesday 9x9, I nearly always have to look at the total sum or total product of all the cells in a particular segment of the puzzle. For the standard pattern, this is usually either the 3 columns on the right or on the left or the top 4 or bottom 4 rows. Whether I use the sum or the product depends on whether the unsolved cages in that particular segment are mainly addition or multiplication. For example, if there are 3 addition cages and 1 multiplication cage, I look at the total sum and this allows me to calculate the total sum of the numbers in the multiplication cage, which generally allows me to calculate the components of that cage (although not necessarily their positioning).

This helps to reduce the number of options and makes the puzzle more manageable.

Posted on: Wed Sep 02, 2020 7:41 pm

Posts: 2
Joined: Fri May 29, 2020 10:31 pm
Re: The 9 x 9 pattern that I most loathe
paulv66 wrote:
prairieboy73 wrote:
What is the trick to solving puzzles like this? I have had limited success with Tuesday 9x9 puzzles. I can pretty quickly find the handful of cells where there are only 2 or 3 possibilities but the majority of the cells have 6 or 7 possibilities and there are some where I can't eliminate any of the numbers at all. When most of the cells have 6 or more possibilities it is near impossible to start eliminating numbers that don't work and I lose interest pretty quickly.

For the Tuesday 9x9, I nearly always have to look at the total sum or total product of all the cells in a particular segment of the puzzle. For the standard pattern, this is usually either the 3 columns on the right or on the left or the top 4 or bottom 4 rows. Whether I use the sum or the product depends on whether the unsolved cages in that particular segment are mainly addition or multiplication. For example, if there are 3 addition cages and 1 multiplication cage, I look at the total sum and this allows me to calculate the total sum of the numbers in the multiplication cage, which generally allows me to calculate the components of that cage (although not necessarily their positioning).

This helps to reduce the number of options and makes the puzzle more manageable.

For this puzzle, I don't see a set of one or more columns or rows that I can use to get either a sum or a product that I can work with. I don't see any grouping of one or more columns that don't contain partial cages. There are also subtraction cages mixed in and unless those have been reduced down just the numbers that actually go in those cages, they throw the sum/product strategy out of whack. Are there specific columns or rows in this puzzle that I should look at?

Posted on: Wed Sep 02, 2020 9:03 pm

Posts: 62
Joined: Tue Mar 10, 2015 5:59 pm
Re: The 9 x 9 pattern that I most loathe
Quote:
For this puzzle, I don't see a set of one or more columns or rows that I can use to get either a sum or a product that I can work with. I don't see any grouping of one or more columns that don't contain partial cages. There are also subtraction cages mixed in and unless those have been reduced down just the numbers that actually go in those cages, they throw the sum/product strategy out of whack. Are there specific columns or rows in this puzzle that I should look at?

I just solved this puzzle, and I haven't come across any analytic way to solve this extraordinarily hard puzzle.
Only using loads of trial-and-error during half an hour, including double guesses, I managed to solve it, with some help of the sum and product strategy paulv66 mentioned above.
Personally, I don't think there exist some columns or rows which will provide you an analytical solution of this puzzle; smart trial-and-error is probably the only way to solve it.
Good luck!

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