Finding The Median Of Two Sorted Arrays
This is one of the beautiful cases where solving the general case first, and then applying it to a particular case is simpler and smoother than solving the particular case at once.
The problem:
Given two sorted arrays, “a” and “b”, with sizes “sa” and “sb” respectively, find the median of the union of these arrays.
Complexity requirements: O(log(sa + sb)) in the worst case, both time and space.
There are a few solutions for this problem, but non of them is as intuitive as the solution of a more general problem: The Select Problem:
Given two sorted arrays, “a” and “b”, with sizes “sa” and “sb” respectively, find the k-th smallest element of the union of these arrays. Under the same complexity requirements as above.
Array Indexing in C
I found this interesting thing about array indexing in C somewhere in the web:
Suppose that “a” is an array. Then, a[5] and 5[a] are quivallent. Both are interpreted as *(5 + a) or *(a + 5) which is the same 
Also: “Hello World”[3] and 3["Hello World"] are the same. Try and C 
Infinite zip File
A nice idea: How to build an infinitely recursive zip file. Details and resulting file here:
http://www.steike.com/code/useless/zip-file-quine/
Have fun
Blogging From BlackBerry
Posting from BlackBerry using Wordpress app for BlackBerry.
You can install the application to your BalckBerry from here: http://blackberry.wordpress.org/install
Have fun
Wisdom by Python (Easter Egg)
An easter egg by python displays a list of quotations, useful in programming and in many cases in life as well.
In your shell, type this:
1 | python -c 'import this' |
You’ll get this:
The Zen of Python, by Tim Peters
Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren’t special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one– and preferably only one –obvious way to do it.
Although that way may not be obvious at first unless you’re Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it’s a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea — let’s do more of those!
via commandlinefu
Have fun
Fix Facebook Chat in Firefox 3.5 (Shiretoko) in Ubuntu
Since I upgraded Firefox to 3.5 (Codename : Shiretoko), I noticed that Facebook chat does not work anymore, moreover, in order to get notifications for new events, I had to refresh the page manually.
After a search at Google, I found the problem, and the way to fix it: Looks like Ubuntu had decided to rename the user-agent into “Shiretoko” which is the codename of firefox 3.5, instead of “firefox”.
Because of the new user-agent name, Facebook does not recognize the browser as firefox, and thus disables some features that are browser dependent.
In order to fix the problem:
1. In the URI bar (that’s the place where you type the URLs of websites you want to visit), type “about:config” (without the double quotes).
2. Click the funny button “I’ll be carefull, I promise”.
3. Now look for “general.useragent.extra.firefox”, right click it, and choose “Modify”.
4. Instead of “Shiretoko”, type “Firefox”. (e.g. if you had “Shiretoko/3.5.4pre” it should become “Firefox/3.5.4pre”.
That’s it, now the world should be a better place
via vimtips.
Embed A Document Using Google Docs
You can embed a document viewer for any PDF or PPT using Google Docs.
You will get something similar to this:
The code I used for the above is:
1 |
Or in general:
1 |
Where DOCUMENT_URL_HERE should be replaced by the document’s URL
via Google Operating System.
Smile
Re-Use A Bash Command With Different Parameters
Suppose you have typed and executed this command in your Linux shell:
1 | ./script_a.sh 1.23 && ./script_b.sh 1.23 && ./script_c.sh 1.23.45 |
Now you want to run the same command, but with 2.34 instead of 1.23
A nice way to do it is this:
1 | !!:gs/1.23/2.34 |
Meaning, run the last command (!! is also called ‘bang bang’, and it’s substituted by the last command you executed), and replace every instance of 1.23 by 2.34
via Unix Bash Scripting.
Have fun
Make Shell Scripts Executable By Default
If you use vim to write shell scripts, you might want to save the “chmod +x” command after saving the script.
By adding the following line to your vimrc file (typically, it’s located at ~/.vimrc), scripts will automatically become executable.
au BufWritePost * if getline(1) =~ “^#!” | if getline(1) =~ “/bin/” | silent !chmod a+x <afile> | endif | endif
(meaning, if the file includes #! with “/bin/” in the path, apply “chmod a+x” on this file).
via shell-fu.
Have fun
Fetch Links From Twitter Into Your RSS Reader
Twitter streams are usually full of links, most of them are shortened by a URL shortener, and filtering them might be time consuming.
A cool service, Readtwit, solves this problem intelligently: Using Readtwit, you can easily create a RSS feed of all links appearing in your twitter stream. The service will fetch the links, and send the full story to your RSS reader. It allows you to filter the tweets (block people and block hashtags).
Neat and time-saving. Try it and have fun
About Me
Hi,
My name is Amir Watad. I have a BSc. in biomedical engineering from The Biomedical Engineering school , Technion , Israel, and am currently studying for a BSc. in electrical engineering at The Electrical Engineering school , Technion , Israel.
I work at the verification dept. in Mellanox Technologies Ltd.
I love Linux, the Command Line and the OpenSource Community.
I used to write Poems (Arabic) when I was able to find time for this.
My name is Amir Watad. I have a BSc. in biomedical engineering from The Biomedical Engineering school , Technion , Israel, and am currently studying for a BSc. in electrical engineering at The Electrical Engineering school , Technion , Israel.
I work at the verification dept. in Mellanox Technologies Ltd.
I love Linux, the Command Line and the OpenSource Community.
I used to write Poems (Arabic) when I was able to find time for this.
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