Rahul Arora

Got this in the Cornell mail

This guide is intended for students who want to enter CS/IT field. The topics that i have mentioned are the ones which i was grilled on during my placement season. I had given interviews in Yahoo, Agilent Technologies, Oracle, PitneyBowes and Flipkart.

My cousin sister is in 4th year of her Undergrad CS program. It is placement season at her college. She wanted some tips regarding placements. What to do? What not to do? Which topics should she study? Which topics she should avoid? Etc Etc Etc. During my placements, i did not have any mentor. Also, i did not realize the power of the internet. So, i decided to write all the things that came to my mind for her. I am sharing this post to all students who are/will be going through placement season in the near future.

A) Programming Languages
You should learn 2 programming languages
Java/C++ and C
Java/C++ because of their OO nature
C because that is the primary language that we all have used during our undergrad

Books

1. Java Book : Think like a Computer Scientist in Java (free pdf)
2. C++ Book : Think like a Computer Scientist in C++ (free pdf)
3. C Book : Kernighan and Ritchie - Amazon link
4. CS-Library@Stanford.edu : Essential C

• Optional but preferred : Do not use any fancy code-editors. Try to code everything in Notepad++ or GEdit (win). For Mac/Linux, use vim (nothing is better than this). I am asking you not to use Visual IDEs because at this stage we are better off without cheats/hints that are provided in IDEs.

B) Data Structures and Algorithms

1. Algorithmic Complexity : You need to know Big-O. It is the first chapter of any Algo/DS book. A must
2. Sorting : Details of O(n) of each sorting algorithm. Advantages/Disadvantages. Also, u need to know how they are implemented in C/Java/C++
3. Queues, Stacks and Linked List : Basic Stuff. A must. Do all possible questions possible on these topics. Refer CS-Library@Stanford.edu for all possible questions on LinkedList.
4. Trees : Again. A must. Do all possible questions possible on these topics. Refer CS-Library@Stanford.edu for all possible questions on Trees. Also, one should know about tree-traversal methods and operations, both recursively and non-recursively. Optional - Balanced trees and tries.
5. Hashtables : Knowledge of Hashtables are required while solving real-life problems discussed during the interview. Candidate should know the working and implementation of Hashtables in any language he/she chooses.
6. Graphs : Rarely companies ask to implement graph-problems. However, u need to know the functioning of graph algorithms, Djikstra, BFS, DFS. 
7. Other problems : 8queen problem, Knapsack problem, Travelling-Salesman are some of the problems that are normally asked in the interviews

Books

• DS Book : Think like a Computer Scientist series covers Queues, Stacks, LinkedList and Trees. However, CS-Library@Stanford.edu is a must to cover all possible questions in these topics.
• Algorithms/Graphs/Hashtables Book : Introduction to Algorithms by Thomas Coreman (Amazon link) is a good book but i preferred reading Anany Levitin (Amazon Link) as it is a small book and contains a lot of real-life problems (that are similar to what is normally asked in interviews)

C) Operating Systems
You should know about Processes, Threads, Concurrency, Deadlocks and Memory Management. There are specific chapters allotted to these topics. Read and understand them from the dinosaur book (Galvin). You can also get Powerpoint ppts from the author’s site. I preferred reading from them.

Books

1. Operating System Concepts - Galvin (Amazon link) or, Ppt slides by Galvin.
2. Modern Operating Systems - Tanenbaum (Amazon link)

D) Databases

Basic Database concepts, Normalization and joins. Candidate should also have good hands-on in MySQL. You should also know basic SQL queries and transactions. Implementation of triggers should also be known [My personal opinion as I was rejected in the final round of Yahoo because of triggers :) ]

Books

1. Sams’ Publishing MySQL tutorial (Amazon link) is my go-to book. Read till Chapter 8.
2. Google University [ For the ones, who finished till Chapter 8 of the above book ]
3. For Triggers : Refer Korth/Gehrke (Amazon link of Korth/Amazon link of Gehrke) whichever book is used in your college. I prefer Gehrke (not because he is my professor at Cornell, but it is a fabulous book)

E) Networking
I never gave Cisco’s interview so, I hardly have knowledge about networking questions. TCP/IP and Internet are two hot topics for all companies. Read about them in detail.

Books

1. Forouzan (Amazon link)/Tanenbaum (Amazon link): Whatever is used in your college
2. or, Head First Networking (Amazon link) : Awesome book. It’s a Head-First. Need i say more :)

F) Puzzles
Almost every company (apart from Yahoo) asked me puzzles. Infact my entire flipkart’s first interview was based on puzzles. They were not programming puzzles, but were mathematical puzzles.
Book : Book of Puzzles by George Summers (Amazon link)

G) Optional

Intricacies of Unix. A must for people who want to become system engineers.

For this, delete Windows and install Ubuntu [ Do not dual-boot, it will not serve any purpose as you will not learn/admire Linux until it’s ur go-to OS ]
Start learning by following Ubuntu/Unix/Linux blogs. The more you will use it, the more you will know about it.

Book : Unix Concepts by Sumitabha Das (Amazon link)

One book i want all interviewers to check out is Cracking the coding interview by Gayle Laakmann (Amazon link). It is the best book i came across. MUST i should say. I bought the pdf version of this book on careercup.com. Buy it even if it’s a lil expensive for books in India. Great value for money.

Note: All the links in this post are affliate links. I got a Disqus post citing “Affliate links, Con-Alert”. I did not understand why I m labelled as a con just because I have affliate links in the post. Hell, I m not even using a url-shortener (Had I been using one, then maybe u can label me as a con). Anyways, they are all affliate links. Kill me for that :P

As a bootstrapped startup, our team at dealites.com are always on a lookout for tools that can help us “do stuff” for FREE. After all, at this stage we need to conserve as much cash as we can.To achieve this aim, this week we are sharing a list of essential tools that every startup needs.

1. Google Apps : Manage your team’s emails, documents and calendar. Free for 10accounts.
2. Springpad : Share ideas and notes with the team.
3. SpiderOak : Online storage with ability to share files, photos and documents from Windows, Linux and OSX. FREE 2GB space.
4. Teamlab : Project Management tool with business collaboration features to schedule project milestones, track project activity and generate reports.
5. Google Sites : Setup an internal wiki with Google Sites.
6. Insightly : Google Apps CRM for free.
7. Wordpress : Open source and free CMS that runs thousands of site.
8. Unfuddle : Subversion/Git repository. Free for 1 active project and 2users. Also includes Bug-Tracking system.
9. Cloudflare : Save your website from online threats.
10. Google Analytics : Track who is coming on your website.
11. OpenOffice : Very good replacement for Microsoft Office that is free and simple
12. MailChimp : Send email newsletters to your customers, manage your subscriber lists, and track campaign performance. Free for lists up to 2,000 emails, with up to 12,000 sends per month.
13. Skype : Free IM, voice and video calling between Skype users.
14. Rapportive : Get info about your contacts right inside Gmail inbox.
15. Google Docs : Manage surveys and validate ideas, new features with users.

If you liked the article please share it on Twitter and Fb.

As a bootstrapped startup, our team at dealites.com are always on a lookout for tools that can help us “do stuff” for FREE. After all, at this stage we need to conserve as much cash as we can. This week we researched a lot of online storage solutions to create our own Personal Cloud where we can access data from multiple computers and mobile devices.

In this post only those tools are included which support Windows, OSX, Android and iOS devices; and give some GBs to their users as free.

1) SugarSync : My Personal favourite
FREE 5GB. +500MB for each invite

Pros:

• Backup any folder on your device
• Select which folders to sync across computers
• Upload / Sync via email 
• Share folders with permissions and password
• Share files of any size

Cons :

• No Linux support

2) Dropbox : What we use in Dealites
FREE 2GB. +250MB for each invite

Pros:

• Linux support
• A lot of tools made around Dropbox.

Cons:

• Backup only 1 folder on device
• Cannot share folders with permissions and password
• File size limit
• Cannot upload / sync via email

3) SpiderOak : One for the Linux guys
FREE 2GB. +1GB for each invite (for you and your friend)

Pros:

• LINUX support (Major game changer)
• Backup any folder on your device
• Select which folders to sync across computers 
• Share folders with permissions and password
• Share files of any size

Cons:

• Upload / Sync via email
• You can only share folders with people in your share-rooms. They also require SpiderOak accounts.

4) Memopal
FREE 3GB. +500MB for each invite

Pros:

• Backup any folder on your device
• Share files of any size

Cons:

• Cannot share folders with permissions and password
• Cannot upload / sync via email
• Cannot select which folders to sync across computers

Legal issues - There are separate plan for Business.

5) IDrive : I personally did not find it good because of the weird UI. It’s one ugly app.
FREE 5GB.

Pros:

• Backup any folder on your device
• Share files of any size
• Select which folders to sync across computers

Cons:

• Cannot share folders with permissions and password
• Cannot upload / sync via email

A PAID Solution
I just cannot resist putting Pogoplug in the list. It’s not FREE but at $29 it is a steal

Pogoplug
UNLIMITED Space for Lifetime at $29

Pros:

• Everything stays on devices. Nothing on the web so very secure for the extra paranoid
• Unlimited devices, lifetime license.
• Backup any folder on your device
• Share files of any size

Cons:

• Cannot share folders with permissions and password
• Cannot upload / sync via email
• Cannot select which folders to sync across computers

To sum it all up, I prefer going with SugarSync/SpiderOak. They nearly have the same features.

In case, you are one-man show and wants to backup everything, go for a PogoPlug. It’s the #1 online backup service on CNET. $29 for unlimited storage and unlimited devices lifetime license is Value for Money. But then, Media streaming is very slow.

This blogpost is my comparison of the two biggest online bookstores in India. Flipkart and Infibeam.

I am a voracious reader. Most of my books are in digital format (Thanks to iBooks) but i prefer reading textbooks in the conventional format. I also wanted to know how “Cash-on-delivery” concept works. So, instead of asking/browsing on internet i decided to follow a more traditional approach. Ask the person who do it. Now finding the person was also a difficult task for a lazy person like me. I ended up buying a book from Flipkart through Dealites. The book “Myth=Mithya” is a nice read for people interested in Hindu Mythology. The online shopping process was smooth. As soon as i check-out, i received the code (specifically for C-O-D), entered it and voila, received a mail citing my book will be delivered in 3-5 days. 3days later, i received the book. I had a chat with the courier guy who told me the nitty-gritty of the trade. The book was packaged in a solid cardbox packing. I was really impressed with it.

After my experience with Flipkart, i decided to try the whole process with Infibeam as well. Their products are sometimes cheaper than Flipkart. So, i went to their website and ordered a book “OS Concepts, Galvin”. The online shopping process was a breeze. I received a mail on April 28th alongwith the tracking id (which was missing in Flipkart). It told me that the shipment has been picked up from North Delhi (Flipkart warehouse) on April 28 itself. On April 29th, the tracking status(http://trackntrace.aflwiz.com/aflwizhtmltrack?shpntnum=82033130204726805) showed “Held for Payment”. 29,30,1,2,3,4 (6 days) have passed and still the status showed the same. What irked me and made me decide to write this post was their reason “HELD DUE TO CUSTOMER ATTRIBUTED REASON”. I called them twice on April 2 and April 3, and everytime they say they will get back to me. When i ask the reason for the delay, he said “It happens sometimes. The person who is handling the area may have forgotten to take it along or his packages may be full”. I was shocked to hear this explanation. But i haven’t paid a dime to infibeam so i was relaxed. Today, i decided i will not be paying for the book. I mailed Infibeam folks and shared the feedback. Hopefully, they will improve upon their service. Also, i decided to write a post and let other users knew my experience of both these bookstores.

Out of both the services, i will prefer people to go for Flipkart even if their price is slightly higher than Infibeam. They deserve it. BTW, acc to Compete.com, Infibeam has 81k visitors to Flipkart’s 189k.

Coinjoos and uRead are next in my review series. Let’s see how they fare up-to my expectations.

(P.S. Again people will be telling me that what happened with Infibeam is 1 in 500 instance. To those, i just want to tell Infibeam ships to atleast 2000 customers everyday. 4 screw-ups everyday and 120 screw-ups every month. Out of these 120, atleast 100 will have pre-paid it. They are struck with it)

[Update : Infibeam does not have a proper order search mechanism. I went to their site checking my OrderID and it’s showing that I haven’t ordered anything in the last month. It, however, is listed on their email which was sent on April 28. No email from infibeam in ur inbox, no OrderID. Wow! ]

[Update 2 : AFLwiz, the courier service is owned by FedEx. Received a call from their head-office. They apologized for the goof-up. I appreciate it. But, no response from Infibeam yet. Even if the goof-up was because of the courier service, Infibeam is responsible for it. It is Infibeam’s responsibility to track packages as well. This also comes in “Customer Satisfaction”.]

[Update 3: I received a call from Infibeam. They apologized about the goof-up. Told me that shipping issues are also their responsibility. I gave my feedback that the orders that i placed was not in my account. Some tech issue i guess. Best part, I am getting the book free. Weird part, FedEx called me to tell that the delivery boy left at 11.30 and the place is 6km from my home. I guess he is coming on foot because 6 hours have passed :P]

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[Update 4: I was promised that the book will be delivered yesterday, May 4 by Fedex. The guy told me that the deliver boy left 11.30. I got a call from the person today morning telling me that i call you 4-5 times everyday why do not you pick my call :O When i was told him that i have already registered a complaint against you and i will show my call log as well (if you superiors want), he mellowed down and told me “Sir gussa mat kariyo, main abhi aa jata hun” (Please don’t be angry i will come asap).

Today, May 5th i received the book. I was told to pay for the book by Infibeam and they will add credit to my account (basically give the book free). I am yet to receive the credit. WHAT PROFESSIONALISM IS THIS? THEY WANT ME TO CALL THEM REPEATEADLY FOR Rs225 NOW?]

I recently made an account on Github. This post serves as a tutorial for new Github users (OS X only).

I am leaving Dealites and will be pursuing M.S. at Cornell University this fall. My work at Dealites involved front-end coding and system administration. After i leave, Puneet will be taking care of my work. To ease up his burden, i decided to help him out by giving him some psds for faster prototyping (We are readying a new UI for our website). However, i rarely keep psd or any other prototyping kit. Mostly i design them by browsing through patterntap.com resources or searching free psds on 365psd.com. So, i decided to write a script to help him download all the free psd’s from 365psd.com catalogued by their name and with their respective image previews (He has Windows, and psd viewing sucks in Windows). I have always been a Subversion user but I heard a lot of positive reviews about Git and i wanted to take a look at Git. So, i decided to make an account on Github. However, for first-time users the whole setup was a pain (I am used to working on Subversion using Cornerstone and the whole repo setup is a breeze). That said, once Git was up and running, it was a different experience for me. It’s so much better than Subversion, however i had a little difficulty understanding the whole public/private repo setup of Git.

Steps

1) Download the latest version of git from http://git-scm.com/

2) ssh-keygen -t rsa -C “your email id”

Hit return and enter a passphrase (No need to remind you that you have to remember it also)

3) Add your ssh key to Github

On the github site : Click “Account Settings” > Click “SSH Public Keys” > Click “Add another public key”

Open id_rsa.pub which is present in ~/.ssh . It contains the public key.

4) Test your connection

ssh git@github.com

Type yes. Success if you receive this message.

»> Hi rahularora! You’ve successfully authenticated, but GitHub does not provide shell access.

5) Now setup your personal info

git config —global user.name “rahularora”

git config —global user.email “your email id”

6) Create a repo : Go to github.com and click “New repository” and fill out the details

7) Setup the repo on your system

git clone git@github.com:rahularora/365psd.git cd 365psd

8) Add a file (README)

touch README

git add README

git commit -m ‘Hello git’

9) Pushing changes to remote git repo at github

This was the step that bugged me a lot. I thought the when i did commit in Step 8, the Github repo will show the new file. But it did not. Github has the concept of public and private repo. The changes one commit on it’s repo is not reflected on the main repo until the person pushes it to the main repo.

git push origin master

“origin’ = Here origin is the remote repo stored on Github’s systems.

10) Thank you. Once you setup, please add me up. This is my github account (https://github.com/rahularora)

A week ago, Microsoft launched http://ie6countdown.com/ to encourage users to upgrade their old IE6 browser to the latest IE9 browser. IE9 is slated to launch on March 14, 2011. The website is “dedicated to watching Internet Explorer 6 usage drop to less than 1% worldwide, so more websites can choose to drop support for Internet Explorer 6, saving hours of work for web developers”. According to the website, the worldwide usage of IE6 is 12%. China leads the pack with 34.5% usage. In India, the usage is 12.3% which in plain terms mean that, 123 out of 1000 indian web visitors use IE6.

The biggest problem is posed by enterprises which use legacy systems. Older version of Windows cannot upgrade their browsers and so, businesses that rely on Windows95 are stuck with IE6. Another problem is in countries where people still use old computers such as China, India, Vietnam, Saudi Arabia, etc. Software piracy is another factor. People who are too poor to buy a genuine copy of Windows, are stuck with IE6 as they cannot upgrade to a newer browser.

IE6 was launched way back in 2003. As the web changed, so does the level of security threats. Being an old browser, it has a lot of security vulnerabilities. The famous Operation Aurora targeted attack that hit Google, Adobe, Juniper and countless other U.S. companies actually exploited a vulnerability in IE6.

Apart from being an insecure browser, IE6 is a developer’s nightmare. There is a common joke in UI fraternity : According to UI developers, there are two kind of browsers: Developer-friendly browser and IE6.  For nearly 5years (after IE7 was released), making websites compatible for IE6 has been a part of the job for every UI developer. A lot of developer time and money is wasted on hiding advanced content and hacking layouts to work around the browser’s bugs.

This browser version needs to die.  Please spread the word.