Why in BFPRT (median of medians) algorithm the partition of the array by $7$ blocks would work but with the $3$ fail?

I am working with the median-median algorithm or BFPRT algorithm and I seek to understand why would the partition of the array by $ 7$ blocks would work but with the $ 3$ fail?

If we divide into blocks of $ 7$ then we will get: Solving it by substitution I think the following manner: It is a recursive tree. In the worst case it takes $ T(10n/14)$ time. So in the worst case it goes down to the bottom by $ (10/14)^kn=1$ steps; $ k=log_{14/10}n$ . At each level of recursive tree the total cost is $ \le cn$ for some constant $ c$ . So by the simplified assumptions using substitution $ k < n$ $ T(n)\le dn \log(n)$

$ T(n) \le T(n / 7) + T(10n / 14) + O(n) \le d\frac{n}{7}lg(n/7)+d\frac{10n}{14}lg(10n/14)+cn \le d(\frac{n}{7}lgn – \frac{n}{7}lg7) + d(\frac{10n}{14}lgn – \frac{10n}{14}lg10/14) + cn = d\frac{12n}{14}lgn – d\frac{n}{7}lg7 – d\frac{10n}{14}lg\frac{10}{14} + cn=d\frac{12n}{14}lgn – d\frac{n}{7}lg7 – d\frac{10n}{14}lg10 – d\frac{10n}{14}lg14 + cn \le d\frac{12n}{14}lgn + cn$

So, $ T(n) = O(nlgn)$

The same way for blocks of size $ 3$ .

$ T(n) \le T(n / 3) + T(2n / 3) + O(n)$ we get $ T(n) = O(nlgn)$

Now, how to show that $ T(n)$ for 7 is also $ O(n)$ and for 3 it can not be $ O(n)$ . Also, in general how can I guess that the $ T(n)$ is also $ O(n)$ because here in both cases my thoughts are they both $ O(nlogn)$ ?

Sharepoint REST call to get file by ID – GetFileById fail on 404

There are some files. when I’m trying to get their content by ID (GetFileById) I’m getting 404 Not found error. I’m getting the file unique id from the item properties and then trying to get the content, and then it fails. Interesting that, in many cases when I’m trying to get same file by relative URL GetFileByServerRelativeUrl I’m getting : The length of the URL for this request exceeds the configured maxUrlLength value error.

So, I actually don’t have any option to download the file. Any advise is welcome.


Swashbuckler rogue: does sneak attack fail if you have both advantage & disadvantage? [duplicate]

This question already has an answer here:

  • Does advantage negate disadvantage (for things such as sneak attack)? 1 answer

I am having a bit of an argument with my DM.

The rules say that you can have sneak attack if “you don’t have disadvantage on the attack roll”.

If I have both advantage and disadvantage, that results in a straight roll when attacking. A straight roll suggests that sneak attack is allowed.

My DM interprets it as, if I have a source of disadvantage, regardless of weather I also have advantage or not, the fact I am being disadvantaged in some way prevents sneak attack from triggering.

Can someone please let me know who has the correct interpretation?

Installing GalliumOS kernel, adding repo seems to fail

I’m a newbie to the Linux world, and trying to get a nice linux install on my Chromebook Pixel. This, it turns out, is not easy.

I’ve been trying to follow this guide:

How to install GalliumOS Kernel onto ubuntu installation Acer Chromebook 14

But when I get to the un-elaborated step “Add the GalliumOS repo”, I run:

sudo add-apt-repository "http://apt.galliumos.org/" 

I get

E: The repository ‘apt.galliumos.org bionic Release’ does not have a Release file. N: Updating from such a repository can’t be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.

And then there is no /etc/apt/sources.list.d/galliumos.list to edit. I try to create a new one, but it wont let me place any files in that folder, and wont let me grant myself permission in it.

What am I doing wrong, here?

sshfs troubleshooting: what would cause openssl to fail?

I believe sshfs requires an sftp server on the remote computer (router):

ipkg list_installed | grep -i sftp openssh-sftp-server - 5.9p1-1 - sftp-server only from a FREE version of the SSH protocol suite of network connectivity tools. 

The goal is to invoke sshfs to mount a remote directory:

sshfs user@mydomain.asuscomm.com:/mnt/CRUZERFIT16/directory/ /home/user/Documents/scpbox/ 

This sshfs setup was working correctly in May, however, a family member reset the router. sshfs returns an error:

remote host has disconnected total 0 

Attempt to remote sftp into router returned:

/opt/libexec/sftp-server: can't load library 'libcrypto.so.0.9.8' Connection closed 

ipkg list_installed | grep openssl returned:

openssl – 0.9.8v-2 – Openssl provides the ssl implementation in libraries libcrypto and libssl, and is needed by many other applications and librari

openssl successfully reinstalled on router:

ipkg -force-reinstall install  openssl 

and am now able to sftp & sshfs into target router. Not sure why openssl was unavailable before reinstalling. Is there a test command to determine if openssl is available for the sftp server?

[ Politics ] Open Question : Does today’s GOP count on the stupidity of Trump supporters, and do Trump supporters never fail to live up to their own stupidity?

For Example: “Fox News personality Tomi Lahren insists that her line of athletic wear stands for American values despite the fact that it is made in China.” https://www.salon.com/2019/08/26/revealed-fox-news-personality-tomi-lahrens-line-of-patriot-yoga-pants-are-made-in-china/ “Lahren recently introduced the line of clothing, which includes yoga pants that have room for packing a firearm. Patriot yoga pants, which feature a pocket for a small weapon instead of a holster, sell for $ 90. According to The Daily Mail, the clothing line is made in China. Lahren claims that purchasing her line is a way of “supporting your president, your country….” …because she knows you are stupid.

JAVA DEPLOY – FAIL – Application already exists at path /MiProyecto

Estoy trabajando en un proyecto en Java ICEfaces, cuando trato de hacer deploy me da el siguiente error:

OK – Undeployed application at context path /MiProyecto In-place deployment at C:\MiProyecto\MiProyecto\build\web deploy?config=file:/C:/Users/JULIAN~1.COR/AppData/Local/Temp/3/context48767.xml&path=/MiProyecto FAIL – Application already exists at path /MiProyecto C:\MiProyecto\MiProyecto\nbproject\build-impl.xml:594: The module has not been deployed. BUILD FAILED (total time: 9 seconds)

Esto no me deja correr la aplicación.

CORS requests for Instagram fail without VPN

My wife’s machine could not load any Instagram content through JavaScript because of the following error:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://graph.instagram.com/logging_client_events. (Reason: CORS request did not succeed). 

I tried getting it to work again, even went so far as to uninstalling Firefox, clearing any Mozilla related data and reinstalling it… same error (default settings, no plug-ins).

Then I noticed she had been logged out of the VPN service (just a commercial VPN service), so I logged her in without giving it much thought. Try Instagram again and… problem solved.

I tried to repeat the above on my own machine, same story:

  • VPN service enabled -> everything works just fine.
  • VPN service disabled -> CORS request for Instagram fail.

My Question(s):

  • Is there any common explanation for this behaviour?
  • Could this point to a compromised router or strange ISP activity?