What I’ve been doing

I haven’t posted anything here in a very long time. Lots of stuff has happened and I’ve longed to blog about them. But, I guess I’m just too lazy. Wish it wasn’t like that. I’ve been busy with third semester courses and preparations for ICPC. We qualified for ACM ICPC both Amritapuri and Kanpur Regionals. But wont be able to attend Kanpur  regionals because they clash with our end semester exams. Now exams are over and I’m eagerly waiting for Amritapuri Regionals.

Programming Camp in Bangalore Campus

As part of our ICPC preparations, Team Bhaktans (Sai, Akhilesh and myself) got a chance to attend a programming camp in Bangalore conducted for Amrita teams from all campuses. Camp was conducted by Harsha Suryanarayanan. Harsha is among the coolest people I’ve met till now. Even his topcoder handle is cool “humblefool“. He introduced us to topcoder. We solved a few problems to get used to the topcoder arena. Harsha gave us a lot of programming tips and taught us how to get better using topcoder. He told us the advantages of coding on paper rather than directly on a PC. This way you don’t have to think while you type and hence lesser chances of making mistakes. And participated in my first Single Round Match (SRM) in topcoder. SRM  is basically a programming game. It is divided into three phases:

• Coding Phase: You get 75minutes to solve the given problems. Now problems fetch you points based on their hardness. The faster you solve them, the more points you get. After the coding phase is 15mins break.
• Challenge Phase: During the 15mins challenge phase you can read codes submitted by other people. If you feel that their code wont work for all the test case then you can challenge them. You can throw test cases at their code. A successful challenge gets you 50points. But a failed challenge sets you back by 25points.
• System Testing Phase: During the system testing phase your code is tested with a big load of testcases. If your code fails either during the challenge phase or the system testing phase, you don’t get any points from that particular problem.

My first SRM was a failure. I couldn’t solve even the simple 250point problem. But I met Gautham and Sreehari of Team Tamals. There is no limit to how many cool people you can meet in a single day. The next day he wound up the session with more problems and tips. This was our first team outing and it turned out to be quite productive and fun filled.

After we returned to college I participated in the next SRM. I think I did quite well. Solved the 250 and 500 point problems and a successful challenge. I’m now green rated. Hoping to improve myself in the future

Hide and Seek in College

All work and no play makes Jack a dull boy

I’m 19 years old and I’m not ashamed to say that I played hide and seek in college. In fact I wish more of my friends had joined me. It must be the design of our college building that made the game exceptionally fun. I’d say its the best strategy game I’ve ever played. Yes, I’ve played Age of Empires and it doesn’t come close. Our college has long corridors so it is a little difficult to outrun the seeker. That made it all the more fun. I cant really explain much about it. You gotta try it yourself.

Hosting Judges

The online round of ACM ICPC Amritapuri regionals was to be conducted and the judges were Anil Kishore and Pratik Tandel. I was able to host the judges. They were really friendly and gave us (Karthikeyan, Nakul and myself) a lot of tips to improve ourselves. The online round went well and we qualified.

Thats all for now. I hope I blog more often

Tags: amrita, bhaktans, harsha, hide and seek, icpc, srm, Tamls, topcoder

InCTF ’12 – National Level “CapturetheFlag” style ethical hacking contest

Yet again, Amrita University & Amrita TIFAC CORE in cyber security proudly present InCTF ’12, National Level “Capture the Flag

" style Ethical Hacking contest.
 InCTF’12 is from November 2011 to January 2012. It is focused exclusively on the student community. You can participate from your own university and no travel is required. No prior exposure or experience in cyber security needed to participate.

Prerequisite to participate is familiarity with any programming language. Working knowledge of Linux is highly desirable but not necessary; learn essential skills as you participate!!!We help you learn if you get stuck!!

What you need to do?
1. Form a team (max five members from your college)
2. Approach a faculty/mentor and request him/her to mentor your team
3. Register online at http://inctf.in

Great Rewards!

25K	The winning team receives a cash prize of up to Rs. 25000/-
20K	The first runner-up team receives a cash up to prize of up to Rs. 20000/-
15K 10 K 5 K	The second runners-up team receives a cash prize of up to Rs. 15000/- The third runner-up team receives a cash prize of up to Rs. 10000/- The fourth runner -up team receives a cash prize of up to Rs. 5000/-

Special Prizes*

• Teams are awarded prizes based on their performance
  

• Deserving teams are well awarded. Exciting prizes to be won.
  

So, what are you waiting for? – It’s simple Register, Learn, Hack!Keep up with us
Website  | Email | Facebook 

| Twitter 

*Cash prizes are subject to their performance and participation in the CTF round. Only teams who connect to the VPN server and successfully gain points in the CTF round are eligible for prizes. In addition, cash prize winners of InCTF '11 are not eligible for prizes in InCTF '12.

Tags: amrita, contest, ctf, hacking, inctf

Contest experience – Infosys CampusConnect Aspirations 2020

This is the first time I’m taking part in a real programming contest. Had so much fun and learned a lot more. My teammates were Sai Vikneshwar (Third year CS) and Aswin Akhilesh (Fourth Year CS). They are really good at this. I’m glad I got this opportunity to work with them. At first I had doubts if I could keep up with them. But it turned out to be a really good learning experience. There were 7questions and 5hours. Within the first our we read all the problems and started with what we felt was the easiest and could be submitted. The problems were pretty tough. The lab was pretty much filled up in the beginning. The contest was a crash course on vectors for me. I had never used vectors before. Knew it was really cool. We had to work using an arena which they supplied. The interface was pretty lame. And we had to stick to a directory structure which they specified. That again was lame. I did not like the lack of freedom. For all the problems they had supplied a header file containing a class and a function. We just had to complete the function according to the given instructions. This was the first time I’m dealing with problems like this. In the problems which I’ve seen before we just had to get the output correct. Anyway we managed to solve one problem. It had no compilation errors and worked perfectly with all test cases we tried. But the arena just refused to accept our program. It was compiling our program as if it was a c program, but ours was cpp. Anyway I learnt a lot today. I was able to keep up with the code Great experience. The last time I sat five hours at a stretch in lab was for our end semester lab exam for C programming in S2. But back then the problems were simple and we were working on mooshak. I really admire mooshak. Its a really cool software and fun to work with. Mooshak gave me my first A+ grade

Oh I also learned a lot about pointers, scope of variables, debugging and is the first time I’m actually noticing varriables getting destructed when their scope ends.

Tags: aspirations 2020, Campus connect, Computer science, Infosys, online judge, programming contest

Operator overloading

Using Operator overloading we can overload operators to work with the classes defined by us. For example: consider I have a class to store complex numbers. I may now overload the + – = operators to work with objects of my complex class the way these operators work with int or float data types. This enables me to add objects of complex data type using the + operator. Well its a lot like functions. The only difference I could figure out was that if you use operators instead of functions, you feel like the code is more abstracted. Moreover I think it’s really cool. But I’m sure that there must have been a more beautiful goal behind operator overloading.

Note that just like a function an operator also has to be called by an object.

I studied operator overloading using the following program.

// to study operator overloading by implementing a class on coordinates of a point in space
#include <iostream>
using namespace std;

class coords {
int x,y,z;
public:
coords() {
x=y=z=0;
}
coords( int a , int b , int c ) {
x=a;
y=b;
z=c;
}
void print() {
cout << "(" << x << "," << y << "," << z << ")" ;
}
coords operator+ (coords op2) {
coords temp;
temp.x = x + op2.x;
temp.y = y + op2.y;
temp.z = z + op2.z;
return temp;
}
coords operator-() {
x=-x;
y=-y;
z=-z;
return *this;
}
};

int main() {
coords p1(10,20,30);
cout << "p1.print()\t\t" ;
p1.print();
cout << endl;
coords p2(1,2,3);
cout << "p2.print()\t\t" ;
p2.print();
cout << endl;
coords p3;
cout << "p3.print()\t\t" ;
p3.print();
cout << endl;
p3 = p1 + p2;
cout << "p3 = p1 + p2" << endl;
cout << "p3.print()\t\t" ;
p3.print();
cout << endl;
p3 = - p3;
cout << "p3 = - p3" << endl;
cout << "p3.print()\t\t" ;
p3.print();
cout << endl;
p3 = p1 + p2 + p3;
cout << "p3 = p1 + p2 + p3" << endl;;
cout << "p3.print()\t\t" ;
p3.print();
cout << endl;
return 0;
}

Output:

p1.print()        (10,20,30)
p2.print()        (1,2,3)
p3.print()        (0,0,0)
p3 = p1 + p2
p3.print()        (11,22,33)
p3 = - p3
p3.print()        (-11,-22,-33)
p3 = p1 + p2 + p3
p3.print()        (0,0,0)

Tags: C, object oriented programming, oop, Operator overloading, programming

Laplace Transforms

I’ve been finding Laplace transforms very difficult. So finally after a lot of procrastination, I’m actually studying it. I guess there would be many people out there in same situation as me. This article is intended for such people who wants to get basic idea about it in very short time.

This is what I understood from class.

Ok this is the equation. But I never understood what it meant until today. Laplace transforms let you convert functions dependent on time to functions dependent on frequency.  Once you get the physical idea, it starts to unfold itself. Here, f(t) is the function based on time and F(s) is the function based on frequency. I used the following links to understand the concepts. Hope you also find them useful.

Khan Academy‘s video lectures on Laplace transforms further enforced the ideas [Link].

The wikipedia page for had a table of Laplace transforms which i found quite useful [Link].

There is a better table available at Interactive mathematics [Link].

The next topic which I found difficult was Laplace transforms on unit step functions [Link].

And this site helped me with Laplace transform of derivatives.

Why use Laplace transform?

I still haven’t figured out this part completely. If you have figured out this part, please comment. I think understanding this part will help develop more interest in the subject. A lil googling told me that they are used in analysing circuits. But I still didn’t understand the how part. I think Laplace transforms are used to study the effect of change in frequency of voltage or current source in circuits where current or voltage varies with time.

Tags: btech, Laplace transform, Math, unit step functions