September 2019
 

[url]http://www.research.ibm.com/haifa/ponderthis/challenges/September2019.html[/url]

Some (trivial) remarks:
The word "set (of banknotes)" is used in two different ways: sometimes it means all existing banknotes (f.e. 1,5,10,20,50) and sometimes it means the notes being necessary for a certain amount of money.
First I have underestimated the problem to find the "unique way" to pay a certain amount "with a minimal number of notes" for a given set of banknotes. Many sets of banknotes are not appropriate, because for at least one amount the minimal number of notes can be obtained in different ways.
I don't know an elegant way to solve this problem and so I had to apply brute force. But the computing times are manageable ("überschaubar").

Sometimes - when I try to open the update of the ponder this website - I have the problem that the status of the update which I can see is depending on the way (device?!) that I use. And in August the second update containing an additional explanation of the challenge and a bigger list of solvers had dissappeared a few days later for one or two weeks. There was only the challenge and the list of the first solvers.
Am I the only one who wonders why there is no solvers list of the September challenge? Or do I not find it?

[QUOTE=Dieter;527136]Sometimes - when I try to open the update of the ponder this website - I have the problem that the status of the update which I can see is depending on the way (device?!) that I use. And in August the second update containing an additional explanation of the challenge and a bigger list of solvers had dissappeared a few days later for one or two weeks. There was only the challenge and the list of the first solvers.
Am I the only one who wonders why there is no solvers list of the September challenge? Or do I not find it?[/QUOTE]

I can't see any solvers either.

To be able to see a page shouldn't depend on the device (unless they really messed up the server to serve only certain devices). Probably, you are seeing a cached copy if they are out of sync.

Just because they are lazy or have better things to do. You can see that "last update Sep 4". I would be flabbergasted (a word I learned on this forum!) if there would be no correct answers, this puzze is quite simple. (Seriously!) Maybe they do have too many answers and are lazy to sort them out.

[QUOTE=LaurV;527144]Just because they are lazy or have better things to do. You can see that "last update Sep 4". I would be flabbergasted (a word I learned on this forum!) if there would be no correct answers, this puzze is quite simple. (Seriously!) Maybe they do have too many answers and are lazy to sort them out.[/QUOTE]

There is a difference between laziness and not having the time...

[QUOTE=henryzz;527174]There is a difference between laziness and not having the time...[/QUOTE]
Well, I didn't say that in a negative way and I am very sorry if understood otherwise. I really appreciate what those people do there, and some of their puzzles are really interesting and very challenging. Many of them I was not able to solve due to same "laziness" or lack of knowledge. Many were simple and not interesting for me, but I guess each of us has his strengths and weaknesses. I am convinced that whoever maintains that site, it does so in their free time, to entertain us (mostly**) and they have real life, demanding jobs, etc.

Meantime, after my former post, somebody sent me PM with the solvers' list updated recently (screen shot), and I was ready to complain of the fact that the list may be regionally restricted, when suddenly it showed for me too, and I was right, there are a hundred persons or so, with the correct answer.

If you still can not see it, then a couple of refreshes of the page may do it.


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**but not always, I still remember the problem with the castle with towers and bridges from the eighties...

[QUOTE=henryzz;527174]There is a difference between laziness and not having the time...[/QUOTE]

I don't think he implied to say that they are the same. He was just covering all the possibilities.

Hi,
The list is updated, in any case I see it.
As of September 24, there are 81 solvers.

[url]http://www.research.ibm.com/haifa/ponderthis/solutions/September2019.html[/url]

Complete list of 5-bill solutions:
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