Game Theory: Problem on Common Knowledge

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Please refer to the example problem from the image attached. Can someone explain why only on 5th day all mothers cry? [Is it something related to ‘necessary’ & ‘sufficient’ conditions?]

How to organize common android UI components such as comment section?

I’m developing a social media app. One of the common components is the comment section. I’m wondering how I can organize my code better to reduce redundancy, because I think it doesn’t make sense if I created the same XML file for every screen that uses the comment section and all the logics needed. But if I make a reusable component will there be any drawbacks, in terms of flexibility and maintainability? I wanted to know what’s the best approach on this.

design patterns – Is there a website to search for architectural approaches to solving common problems?

Suppose I want to build a graphics editor app.

Is there a place I can go (google isn’t helping) to find out what different people have done, how they’ve been able to extend on their design, etc?

Sort of like a search engine where you search for some feature/system capability and the results are solutions and different approaches one can take?

And maybe those are broken down by technology used:

  • web, dekstop, mobile, etc

algorithms – Find if two numbers are linked by a greatest common divisor

Two numbers $x,y$ are ‘connected’ if $gcd(x,y)>g$. Here $gcd$ is the greatest common divisor. A path exists between two numbers $x,y$ if given $g$ and $n$ there is a sequence of numbers that connect $x$ to $y$ such that all numbers along the path are less than or equal to $n$.

How do you find if there exists a path between two numbers and if this needs to be repeated for multiple pairs of numbers would it be more optimal to first find all existing paths.

I’ve tried a basic approach of breadth-first search, where each query between two numbers involves calculating $gcd(x,y)>g$. However, this is quite laborious and want to see if there is a more optimal solution.

algorithms – Find distinct groups with no common parents

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How do we move Azure Data Lake Gen2 Bronze(RAW) zone data to Silver Zone in Common Data Model (CDM) ? Please let me know the process

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seo – Disallow dynamic URL paths ending in a common suffix using robots.txt

I want to block Google from crawling the following URLs:

which one is appropriate?

tonga, india, usa, uae etc are dynamic variables

Disallow: /*/posts    
Disallow: /*?posts=
Disallow: /*=posts 

Connecting common points on a map

I work with a private preschool – 12th-grade school. The school has several campuses. And each campus has several hundred families. We have two separate spreadsheets. One spreadsheet has all of the parents’ home addresses and the other spreadsheet has all of the parents’ work addresses. We’re using a mapping software called eSpatial (but it’s limited). We can upload the spreadsheets (datasets) and map both batches of addresses.

The problem is that this doesn’t really tell us very much. Ultimately, we need a way to link home and work addresses together, visually, as being the same person.

For example, let’s say one point on a map is a parent’s home address at 123 Main St. and another point on the map is the same parent’s work address at 321 Sycamore Rd. We need a way to visually know that the two points below to the same person so we can see who, and how far, each parent travels to work. Ideally, if there was a line that connected the two points that would be great. That would make it easy to see how far away the parent works. Or it would also work to hover over one point and the corresponding home or work point would highlight.

Currently, the two spreadsheets do not have a common column that links the two together (I guess a “key”). Although I can create a spreadsheet that has a student ID column which would be the key between the two.

Any thoughts on how to put something like this together? Hopefully, this makes sense.

hygiene – Is sweating more common during air travel?

I also tend to feel sweaty during and after long flights. I’m not sure if there is any hard research showing that it is or is not more common. I would personally guess that it is, but I don’t have any evidence to back it up.

However, it’s certainly possible that certain people do sweat more. You say it’s the case for you, and I feel that it is for me personally as well. Why is this the case for some people?

Long time in one position against seat

You’re typically sitting in the same position for many hours. This means that there is little or no air circulation between your body and the seat. It also depends on the quality of the seat, but it’s quite common for it to get clammy due to your backside being pressed against the seat for long periods of time.

Long time, no shower

Canton to Sydney, which is quite a long trip.

In this example, you may be traveling for 35 hours or more. In that case, there is a simple answer: You’re going for quite a long time without showering. (It’s, of course, possible to shower during the layover or even on the plane, but most people don’t.)

Normally, most people shower/wash themselves at least once a day. Some people do it twice a day. There are good reasons for that. Sweat, salts, etc. accumulate on the body, causing various uncomfortable sensations for oneself as well as others. Long air journeys can take much longer than that, sometimes causing you to not shower for > 50 hours. Perhaps, if you went that long without a shower unrelated to flying, you would notice some buildup of sweat too.


This may not be something you (OP) personally suffer from, but many travelers do. Cold sweating is one of the symptoms of airsickness.


I don’t know if this applies to you, but a lot of people can get slightly stressed while going on long journeys. They have to pack everything, remember everything, perhaps get up in the middle of the night, have their documents in order, keep track of their passport and money, be on time for everything, pass security, customs, immigration, guard against theft, wait in lines, experience lack of sleep, etc. Most people (including me, certainly), can feel mildly stressed due to all this. It is a well known fact that stress increases perspiration.

Lack of sleep

Even if you are a seasoned traveler who don’t feel stressed at all, and even if you’ve managed to shower during your journey, it’s likely that your journey interferes with your sleeping patterns. You might get some sleep during your journey, but it’s not going to be the same quality that you would normally get. Lack of sleep may possibly cause increased perspiration. Your body is tired, and has to work harder to perform its normal functions.

Airplane air

Here’s a final point that I expect to be (and welcome being) challenged on, but I’m including it anyway: The air in airplane cabins is extremely dry. This may cause the body to compensate by sweating, etc. Of course, water also evaporates much faster in the dry air. However, only the water evaporates. The salts and other components of your sweat all remain on your skin/clothes. This may increase the feeling of being sweaty. (Again, I do feel that this last point is somewhat speculative, so I’m including it more as a hypothesis than a fact.)

Shower right before departing. If possible, shower during layovers. As @pnuts said, wear antiperspirant. Try to relax as much as possible during your journey, and try not to be in a hurry for or very worried about anything. Wear clothing that breathes well. Get up from your seat regularly and stretch a little bit. Bring extra sets of underwear/shirts/other clothing and change in the bathroom when you feel sweaty. You may even bring body wipes to clean your skin and reapply antiperspirant on clean skin. Do whatever you can to get enough sleep. If you can afford it, get business class which is much easier to sleep in. If you’re rich enough, and it’s available for your route, consider flight tickets that give you access to an in-flight shower.

Personally, I don’t bother with all of this (although I certainly do some of it). I’m just trying to answer the question on how to counteract excessive sweating, though. To which lengths you may want to go would depend on how important this is to you personally.

SQL JOIN QUERY with more than one items in common: Find the franchise pairs that operate together in more than one location

I have a table called dfmt that lists the location, revenue and franchise. I want to find the franchise pairs that operate together in more than one location.

Some sample data

So far, I have a query that finds the franchise pairs that operate in the same location:

select, T2.fr2 from dfmt T1 join (select fr as fr2, loc as loc2 from dfmt) as T2 on < T2.fr2 and T1.loc = T2.loc2 order by loc;

I do not know how to go from here to find the franchise pairs that operate together in only more than one location.

Another query that may be useful that Finds the franchise that generates the maximum revenue in more than one location.

select fr, count(*) from tst2 where rev in (select max(rev) from tst2 group by loc) group by fr having count(*)>1;
enter code here