15 Mar, 2015
AVL trees are great, but it's very easy to be intimidated by AVL tree rotations for a beginner. Gaining an intuitive understanding of AVL trees is important. The supposedly "hard" part is the AVL tree rotations. Initially, it can seem all a bit random. But, I hope to demystify it for you.

What is an AVL tree?
An AVL tree is very similar to binary trees. A binary tree is a data structure in which each element
(1) is the child of another element (also called the parent node),
(2) and can have at most 2 children.

The one exception to this rule is the root element (or node). The root node does not have any parent and is the first or top-most node in the binary tree.

A Binary Search Tree is a clever modification of the binary tree by adding a certain condition. For example, I'll say that all the children of a node whose value is less than the node in question will be placed to its left. Similarly, all nodes greater than it will be placed to the right.

The great thing about a binary search tree is that it's very easy to find an element. Try searching for the node 5 starting from the root node. You'll notice that starting at the root, you don't have to traverse the right sub-tree since 5 is less than 10. We go down the left sub-tree leading us to 8. Again, 5 is less than 8, so we traverse the left child of 8 to reach 5. This is the power of binary search trees(BST).

Why did I say AVL trees are great at the beginning?
AVL trees solve a problem that plagues binary search trees: a BST can become unbalanced. Let's say I've a BST and I want to randomly add numbers from 1 - 100. If the first number that I add is 1, the root node becomes 1. All the other elements now add along the right sub-tree of the root node.

As you can see, the tree above is unbalanced. The height of the sub-trees are displayed in the image. The left and right sub-tree heights of the root is 0 and 3 respectively. The disadvantage of an unbalanced tree is that you tend to lose the primary advantage of a BST, i.e., reduced number of comparisons to find an element. In the worst case, you could even end up with comparing all elements in the BST which is what we are trying to avoid.

AVL is the solution
AVL trees are BST's at their core, but have an additional condition imposed upon it.
AVL property:
Every node in an AVL tree must satisfy the property that the heights of its left sub-tree and its right sub-tree can differ at most only by 1. This ensures that the tree is always balanced.

How is this achieved?
After the insertion of a new element in to the AVL tree, we check if the AVL property is satisfied. If not, we modify the tree so that it becomes an AVL tree again. These modifications are usually called AVL tree rotations because, intuitively, that's what they are.
(Read the rest in Part 2)

12 Mar, 2015
It's been a very long time since a new game has come out from Vitarsi's stable.

Air Warrior: Domination or AWD is the reboot to a very old game that I made when I was in school. AWD is a top-down (or even 2.5D) dog-fighting game. No prizes for guessing, the objective is to shoot down your opponents Top Gun(Link) style.

What's the best part? It's multiplayer! No better fun than shooting down your friend right from his 6 o'clock. It should support up to 4 players simultaneously. With 5 or more, the lag will become more than noticeable.

Is there a single player mode? Hopefully.

It's still a work in progress. But, you can try out the beta version from here:http://downloads.vitarsi.com/AirWarrior.zip

26 Jan, 2015
Nokia was ubiquitous. They were all over the world, dominating the mobile phone markets everywhere. But in its glory, Nokia made a mistake in not jumping on to the Android bandwagon and soon lost out to competitors like Samsung. Even Windows for its phones could not save Nokia. As you might know, Microsoft bought Nokia's ailing mobile phone business last year. Everyone thought that that was the end of Nokia.

Nokia N1
Presenting the phoenix -- out from its ashes, Nokia is betting it all on this.

What is it? Hold on. Nokia recently launched a new Android Launcher called the Z Launcher. The Z Launcher takes inputs in the form of scribbles to let you quickly search for apps. Given that on average, we seem to have over 100 apps on our phones, this seems to be a nice idea. It's available on the Play Store (Link). It's not available in India currently (What's up with that, Nokia?). It can learn what apps you tend to use at what time of the day, and suggests apps to you.

Buoyed by its success with the Z Launcher, Nokia has announced a new Android Tablet. It's got a 7.9" screen and is powered by a 2.3 GHz 64-bit quad-core Intel processor. It's got the Z Launcher running on top of Android L. It's the first device to have a Type-C USB port (yes, that's the new reversible type of USB port). Saves us from fiddling with the USB cable -- "is it this way, or that way, no the first!".

Is it just another tablet on the market, albeit, with a quirky launcher? Time will tell.

A resurgent Nokia is (rightly so) quite proud of it -http://n1.nokia.com/en.
You can watch the Nokia N1 reveal here -http://youtu.be/8LoWySr_EYA.

25 Jan, 2015
Apple had been lauded over the years for its innovative products. But recently, Apple seems to be losing its sheen. The newly launched Apple Watch(Link) was more of a let down. With Apple's standards, the Apple Watch was just like its competitors, and proved to be nothing special. The iPhone 6 and 6+ just goes to show that even Apple will bend over to pressure from the industry for larger devices. Up until that point, Apple was smug over its small, fits-in-the-palm phone.

Move over Apple, here comes Microsoft

The internet world is going crazy with each new release of the demo build of Windows 10. The "Start" button that went missing in Windows 8 is back (thank God!). It also incorporates a new notification panel, much like the Android notification drawer. This would have notifications from applications (like Skype). Probably newer applications can take advantage of this. Calendar notifications, reminders and such. The tablet experience is getting closer to the desktop. Hopefully, Microsoft will be able to achieve with Windows 10 what it wanted to with Windows 8.

HoloLens is the new augmented reality headset that Microsoft announced recently. The marketing video above is exceptional. Google Glass pales in comparison (Link).

Microsoft plans to release the final product within Windows 10's life-cycle, which means no fixed-date yet. However, it's much too early to comment as Microsoft has only showcased prototypes of the thing. For now, it runs demos. (I really, really want to play Minecraft with that thing!)

I, on behalf of us all, plead to Microsoft, please get that thing on to the market. Don't screw this up!

You can head over to the official page here -http://www.microsoft.com/microsoft-hololens/en-us

23 Jan, 2015
Nuclear power! Anything with the word Nuclear in it suddenly becomes something else. Nuclear missile, Nuclear submarine, Nuclear families, Nuclear force, Nuclear power (, Nuclear sandwiches?).

If the radiance of a thousand suns were to burst at once into the sky, that would be like the splendor of the mighty one.
Oppenheimer had recalled the above verse from the Bhagavad Gita (Link) when he witnessed the explosion of the first nuclear bomb test, earlier in July of 1945.

8:15 a.m., August 6th, 1945, saw the arrival of the Nuclear Age along with the horrendous power that it bestowed upon us. The United States used the first of only 2 nuclear weapons ever to be used in war (and dropped the second 3 days later).

These bombs were fission-based, which means the explosive power of the atomic bombs came from the uncontrolled chain reaction of fission of a highly fissile material such as Uranium or Plutonium. Soon enough, fusion weapons were designed with even higher yields. Total world annihilation was imminent.

Ironically, nuclear weapons which were much touted as Weapons of Mass Destruction (WMD's), became the best deterrent for all out war and prevented the world's super powers from going head-to-head in World War III.

Then came the nuclear power plants. A very efficient way of generating power. In fact, the Voyager I spacecraft has a nuclear power plant that's been driving its electronics since 1977. It's expected to be productive until 2025. Wow, indeed!

To get a feel of how power plants work, you can take a look at the following link. It is a simple game that lets you play the part of a nuclear power plant Technician (think Homer Simpson).

The objective of the game is to extract as much power from the plant as possible with the fixed amount of nuclear fuel. You can control the rate of primary coolant flow in to the core, the secondary coolant in to the heat exchanger, the control rod position, etc. You can even cause a meltdown!

Head to this link to try your hand at optimum power generation -http://esa21.kennesaw.edu/activities/nukeenergy/nuke.htm (This requires Flash Player though)

"Homer Simpson 2006" by Source. Licensed under Fair use via Wikipedia -http://en.wikipedia.org/wiki/File:Homer_Simpson_2006.png

05 Jan, 2015

For generations we had used 'Rs.' for displaying prices everywhere. There was no "symbol" for the Indian currency, the Indian Rupee, until 2010 that is. That's when the new '₹' symbol for the Rupee was finally declared, officially, to be the symbol for the Indian Rupee. However, the other nations that use the Rupee for their currency (like Pakistan, Sri Lanka, Nepal to name a few) still use the 'Rs.' to specify the currency unit.

For Windows users, you can go over to the Microsoft download website to get the update. Link

After the update and reboot, you can start using the new symbol with the "Ctrl+Alt+4" combination.

04 Oct, 2014
When Windows XP first came out, we were all living with 98 and 95 which were not very dissimilar in appearance to each other. The world (or rather, me) didn't really have much of an idea of what to expect other than a new OS. But when XP came out, I was awestruck. The blue taskbar, the green Start button! Everything was amazing!

The same thing happened with Vista. Transparent taskbar and windows?! How? How much processing power is being wasted for these effects I thought then. But Vista was beautiful, at least when comparing it to XP. It was, I'd say, a beautiful cousin of XP because the underlying mechanics were similar. The "killer" feature was the Windows Aero, the feature that was to cure cancer. However, it was not to be, and it turned out to be just an over-glorified task switcher that hardly anyone uses because it is redundant due to the existing Alt-Tab switcher which works sufficiently well.

When 7 came out, I laughed. I was a Vista user at the time (and I still am). 7 seemed more like a tweaked Vista at the time and never gave it its due credit. However, after using 7 for a while, I have come to appreciate its many feature additions compared to Vista. I'd say, 7 is the best OS out of the Microsoft stable.

When 8 came out, I was not convinced. I liked the idea, seamless experience between phone, tablet and desktop/laptop. But the desktop version is half baked. It's halfway from 7 and the future. It's neither here nor there. The desktop is all 7-ish, but some parts of it have not been done right. Probably my views on 8 will change if I use it extensively like it did with 7. But for now, I would rather bet on Windows 10.

I guess the feedback for 8 was so bad that Microsoft even skipped a whole version number and jumped straight to 10 from 8. Exciting times are ahead of us.

Follow this link for some preview images from the yet to be released Windows 10. Link

30 Sep, 2014
Regular Expressions are a very handy tool in a developer's arsenal. They can be used to do string replacements quite easily. However, regexes can be daunting at first since the regular expressions can look just like garbled text. But simplicity beats all and I want to show you a simple use of Regular Expression for string replacement. Sample this:

var text = "This is a test text. And I have a fish.";
alert(text.replace(/(fish)/g, "gold $1"));

What does the above do? /(fish)/g is the regular expression for strings of the form "fish". The replacement string just replaces it with gold fish. Here $1 represents the first match. First I say because, fish is enclosed in parenthesis. If there were more expressions enclosed in (), then they would be matched witch $2, $3 and so on. $0, as you might wonder, represents the entire matched string.

Something useful would be to do BBcode replacements like the following:

text = text.replace(/[b]([\S|\s]*?)[\/b]/g, "<span class='boldText'>$1</span>");

The above replaces text enclosed with [b] and [/b] with real HTML tags.

These are the simplest of cases where Regexes come in real handy. You can experiment with Regexes at this cool site called Regex101.com (Link).

05 Jul, 2014
Ever wondered how many photos there are on Facebook? Every day you and the people in your friends list alone upload so many photos that there's no way you can keep track of them all. At that rate, how many photos do you think are uploaded every day by the billion strong users of Facebook? A jaw dropping 350 million+.

There are over 250 billion photos uploaded since the very beginning of the website. Where does all of that go? I haven't even mentioned the videos, status updates, likes, pokes, messages, comments and other posts shared every second.

Facebook, from the very beginning, knew the importance of "uptime", or what we can refer to as the "always on" factor. What this means is that they have always invested big in their servers so that they never end up with server down time. Server down time always means one thing: disappointed users. If your users are not getting what they want, they are only a split-second away from finding the next best alternative. So what are they doing about it?

They have huge server farms. Yes, that's what they are called, farms. Probably because they operate the servers there, feed them, take care of them, and bring more as their need increases. Just like what you'll do with cows in your everyday farm. Facebook says that it stores over 300 petabytes of data in there. Now what is a petabyte?

1 petabyte = 1024 Terabytes = 1024 x 1024 Gigabytes = 1024 x 1024 x 1024 Megabytes

Unfathomable, to say the least. Nowadays, most people don't know what a floppy disk is. So, I'll go with CD's. A CD stores about 600 MB. If I do a little bit of math, I get 53,68,70,912 CD's worth of data to hold 300 petabytes. A CD is 1.2 mm in thickness. If you were to stack that many CD's, it will be over 644 km in height. Maybe that's a bit of perspective.

03 Jan, 2014
Ever felt your Android lacks the traditional "silent" mode? Now, with this app you can make your phone truly silent. Mutes all audio channels on your Android device including ring, notification, alarm, music and system volumes.

Available free on Google Play: Link

03 Jan, 2014
Want to manage finances within a group of people? Then EagleShare is the thing for you. Register for an account for free, ask your friends also to do the same. Then create a group for yourself. Add your friends and then you're set. Add activities. Activities are records of who spent how much money for whom on what. Once this is done, you can create reports instantly. EagleShare generates month-wise reports.

This EagleShare website was designed out of a serious need for such easy calculation of finances. Check it out here: Link

18 Nov, 2012
What would it be like to travel inside a Black Hole? If you actually jumped in, you wouldn't live to tell the tale, that's for sure. But, out of curiosity, what is it like jumping into one? Here's a video by Vsauce (Link).

18 Nov, 2012
Did you know that YouTube has an in-built Snake Game to spend the time while buffering a video?

This works in fullscreen mode also. When the video is loading, just press the Up or the Down arrow key. The loading graphic turns into a snake and voila! Your time killer, especially, for all those people who don't have lightning fast internet connections.

14 Nov, 2012
DugleeIT News is a one-stop destination for all of your online reading pleasure. This handy little app has numerous links to various popular websites like LifeHacker, Gizmodo, National Geographic, to name a few. And as the name suggests, it's got links to many news websites, all categorised by continents and further country-wise. So, reading news is so much easier with DugleeIT.

I really loved how comprehensive this app is when it comes to the number of links provided. It just about covers everything you might read online. Lots of categories to choose from too. So is this just an app with links? NO! Don't get me wrong here, when you click on a link, it opens the website within the app seamlessly. No nonsense. And brilliant!

Well, this is the first app featured on this website that was not made in-house. This was developed by a recent start-up called OctOM. I'm definitely looking forward to more apps from them.

DugleeIT is available on Google Play and it's free: Link

31 Oct, 2012
Here's a very handy no-nonsense compass app. The compass, as you know, points to magnetic north. It is as good as any real compass (and by that I mean, a magnetic strip of metal suspended in metallic or plastic casing) in terms of finding magnetic north. Here's an in-app screenshot.

Available free on Google Play: Link

31 Oct, 2012
We live in exponential times. We use so many things on a daily basis that they have become such an integral part of our lives, and yet, these things did not exist even a decade ago. Such, is the rapid rate of technological advancement. Take for example the mobile phone. So ubiquitous, that we hardly give a second thought to it. Such a thing was Sci-Fi during our parents' times. Below is a mind-boggling video from YouTube.

So, what do you've to say about the future? I know, you can't say anything.

26 Oct, 2012
JuMp for Android is based on the PC version JuMp made way back in 2009. The game is very simple and good for killing some time.

Your goal is to jump as high as possible. You can make 5 successive jumps before reaching the ground (similar to double jumps in other games, but you get to do 5). The point is to collect Accelerators that appear as you go higher. They increase your speed so that you can go higher than by simply jumping. The more Accelerators you get in quick succession, the faster you go up. Bonus jumps (small blue arrows) will refill your "jumps" so that you can jump 5 more times before you fall to the ground. Falling to the ground refills your jumps to 5. And yes, falling reduces your health. Run out of that and it's game over. Go really high and birds will start pecking you. Avoid them or you'll end up losing your precious health.

Get the Android version here: Link
If you're interested in the PC version, get it here: Link

15 Oct, 2012
Resimho is a very simple to use resistor value calculator App available for Android. Resimho has been tested on an Android 2.2 device and should work seamlessly for any higher versions.

Simply select the 4 different colours found on the resistor and the app will calculate the resistance. Not much, but, it does come in handy when you're in the workshop creating something and happened to have forgotten the colour code values.

Available free on Google Play: Link

18 Jun, 2012
Here's a quick tip for you. Every time you use a microcontroller (like PIC, AVR, anything for that matter) in your project, you'd definitely have a main loop that keeps looping the entire time. So, the best way to know if your microcontroller is indeed working and that it has not reset itself or done something funny, is to just toggle an output at the end of the loop. You can connect this to an LED with a resistor. Below is sample Assembly code for PIC.

         (some code here)

         BTFSC PORTB, 7
         GOTO turn_off_led
         BSF PORTB, 7 ;turns on LED
         GOTO main
         BCF PORTB, 7
         GOTO main

The LED connected to the 8th bit of PORTB keeps toggling after every loop, so you can tell whether the microcontroller is executing the program and is not stuck.

17 Jun, 2012
A very simple wanderer bot controlled by a PIC16F877A. Watch the video below to see the bot in action. Wanderer Bot detects collisions with the help of a unique mechanism and tries to avoid them. And what's the most striking feature of it? It was built completely in just 2 days (or nights rather).

The video:

17 Jun, 2012
Have you ended up trying to create a PIC controlled robot/device and surprisingly nothing seems to work when the motor is connected? Well, here is a checklist to avoid that very problem.

You might have a PIC controlling a motor through a motor driver IC like the very commonly used L293D. The problem is, every time the motor is turned on, it pulls in a large current upsetting the entire circuit. Because of this, 'Brown Out Reset' causes your PIC to, you guessed it, reset. So have this disabled.

An important thing is a capacitor across your motor. Any small value capacitor will help avoid noise and interference.

A large value capacitor across your +5 and Gnd is a very good habit. This will help stabilise the voltage across your entire circuit.

Another lifesaver of a tip is to never switch on your motor in the start of the code. Something like this may not work.

start motor
call delay
goto begin

This pseudo code may not work because as you power up your circuit, the PIC tries to switch on the motor, and this causes the PIC to reset. Instead, do something like the one below. The delay in the start will let the voltage to stabilise first.

call delay
start motor
goto begin

Following these simple tips will turn out to be a lifesaver when you're frustrated when nothing with a motor works right.

17 Jun, 2012
Well this is a handy feature that most people are not aware of. You might be creating some tutorial or any other thing for that matter and you happen to need some screenshots of your android screen. Believe me, I've seen people use other cameras or phones to take pictures, which gets a big hands down.

The way to take screenshots is to hold down the Back button and then press the Home button. A PNG file will be created in /sdcard/ScreenCapture.


27 Apr, 2012
LaTeX is a program designed to produce very high quality typesetting. They're normally used for preparing documents such as scientific papers and other documents related to academia. It is especially good for mathematical symbols. The other alternative is using Word, but we all know what a pain that can be once the number of equations starts to increase.

Well, getting started with LaTeX can be a pain too, so here I've made a quick reference guide for beginning with LaTeX. Only the basic formatting is covered right now. Mathematical symbols and equations will be added soon.


26 Mar, 2012

Epic follows the epic battle between the Roolans and the Xedites, two races of species set in the future. A classic top-down shooter with various missions to complete. Also features a Random Map to let you play different scenarios.

The unique aspect of Epic is that it combines the features of an RTS and an arcade shooter. You scour around the game world with one spacecraft, but you can call in reinforcements to help you. However, to do so you need to collect Galactican cash. This you do by escorting(or rather hanging around) Motherships. The more Motherships under your control, the better since the rate of cash in-flow increases(pretty straightforward don't you think). And what's more, Motherships aligned to your side repair your ships as well.

Don't sweat it, the game has a tutorial that'll teach you the basics of the game. However, it's still a Work in progress and you might see a bug if you're really unlucky.

Here's the link to the game's page. Link
Mirror: Link

26 Mar, 2012
Vitarsi Tech. strives to bring the latest in sci-tech. happening around the world. We'll bring you awesome stuff, rest assured, you won't be bored anytime here.

Also, we're in to software design, so we'll be regularly posting our software as well. This includes games and websites. Do check back often as change is the custom here.