Need Motivation?

Tags

great quotes, life, motivation, need motivation?, quotes

Finally Graduated…

31st May 2011
I was waiting for this day for the past many years, but really can’t believe that it has finally come.
Today I finished all the exams of my 8th semester at DCE, Now only the final result is awaited, and getting the degree is just a formality. But anyway I am out of the college now. Throughout the 4 years I regretted my stay at DCE. but at the end I bagged a good enough placement(at US ) and met great people. you can’t expect more from a college which is governed by Delhi government and winning a seat in election is far more important than imparting education.

A Fun day at DCE

Taming the WUBI Grub daemon

Tags

error, grub, not mounting, panic, root disk, ubuntu, wubi

If you are not an advanced unix user and you have installed ubuntu via the WUBI installer. Then you might face this problem sometimes.

How I define this problem:
When I started my computer and chose ubuntu from the boot-menu I got a black-screen with nothing but Grub>
When I put the live CD and tried to mount the root disk of my Ubuntu, it failed with input/output error (apparently due to FS errors in the root disk) .

Solution:

1. Go to windows and go inside your wubi installation files and locate root.disk
2. Try to copy this file to some other drive(Note that this is a huge file)
3. If the copying is successful, it means that there are no file system errors in your root drive and you can easily retrieve your data using a live CD and you might like to retry this (If your CD drive doesn’t work you can create a bootable USB also, which works same as CD or even better)
4. If the copying fails with some weird error code, it means that you have file system errors on this drive(common in old hard drives), Lets fix them!
   • Start windows
   • Run CMD as admin
   • Enter chkdsk and press enter, wait for the output
   • Enter chkdsk volume: /f , where volume is the disk label of the drive in which ubuntu is installed. For me it was D. /f means fix it. Wait for the output to come.(This might take a lot time)
   • If all the above steps completed successfully, it means that you have successfully fixed the fs errors in the drive. So reboot the system and try to access ubuntu from the boot menu. It should work, If it doesn’t  then try to mount the root disk manually using this

How to use Yahoo! term extraction service with PHP

Tags

keyphrases extraction, PHP, term-extraction, Yahoo

Yahoo provides a term extraction web service by which you can extract important keyphrases from a given text.The service is accessible via Yahoo Boss.You will need a Yahoo! BOSS Application ID to use it. It’s free of cost, so get it

Then you can use the PHP cURL  function to post the variables to the specified URL and return the result to a variable($xml here). The function I used if pasted below:

PHP Function:

function getKeyphrases($texttoprocess){
// cURL must be installed for this to work
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, ‘http://api.search.yahoo.com/ContentAnalysisService/V1/termExtraction’);       curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt( $ch, CURLOPT_POSTFIELDS, ‘appid=PASTE YOUR YAHOO BOSS APP ID HERE&context=’ . urlencode($texttoprocess) );
$xml = curl_exec($ch) or die(‘error’);
curl_close($ch);
return $xml
}

The sample working code with HTML GUI could be downloaded from here.(Don’t forget to add your App ID in yahoo.php file)

Multiplying 2 huge numbers

Tags

C++, huge-numbers, string multiplication

Multiplying 2 huge numbers is a very common problem in programming competitions and interviews.I am attaching my code for this problem.

My algorithm:

1.Input the 2 numbers in a string say S1,S2

2.Consider one of the 2 number say S2 as a collection of many single digit numbers eg if s2=”3243″ then it is a collection of ’3′,’2′,’4′ and ’3′

3.Multiply each such digit with S1, taking care of the carry

Follow this link for the c++ implementation which handles upto 1000 digit long unsigned numbers.The code is well commented.If you come across any bugs in it,please let me know by post it here!

My code is not perfect, of course there is a scope of improvement.

My first Job, yahooooooooooooooooooo!

27th october 2010(yesterday), the most remarkable day if my whole life, I got my first Job and guess the recruiter….well its Yahooooooooooooooo! I am loving it.
I woke up a bit earlier yesterday, got ready and reached TnP sharp at 9 am, shockingly the Pre Placement talk started at its scheduled time(which is generally rare). It was a great talk, we really got to know how big the brand Yahoo is and how cool the environment at Yahoo is. PPT continued for alomost 1 hr then we all were moved to auditorium for the written test. I was pretty much nervous, as my performance in the past written tests doesn’t worth mentioning.
WRitten test consisted of 25 MCQs with 5 options in each question, there were questions from topics like multithreading, Processes,Algorithms complexity, data structures, Counting etc. The paper was entirely based upon the fundamentals. If you have done fundamentals well, you’ll clear it. 20 people were shortlisted for the coding round.
COding round, We were given the problem of implementing the unix utility ‘grep’ I didn’t really do good in that round but still I was through
Overall 7/20 could clear the coding round.
FIrst interview, This interview went quite well, my interviewer was from DCE itself, so I got the benefit I guess, He was basically checking my fundamentals, he asked me to improve the best case performance of bubble sort, then a good discussion on quick sort,  one quick puzzle, a lengthy discussion on my GSoC project and some fundas of web development(dcetech.com)
SEcond interview, This interview was a disaster, My interviewer was the most senior member of the Yahoo team and threw a lot of good questions, I didn’t actually answered them very well, but still I was through .They really liked me
Only 3 people were called for the 3rd interview, It was basically based on though processing, He asked me problem which is under active research and I has a good discussion with my interviewer, It was really fun.Again I was asked about the GSoC project(the work I did for Mozilla) and then my language preferences.
Next was the HR interview, It was just a really casual talk and I enjoyed it thoroughly.
Finally we all were asked to wait for sometime.
Then HR came and announced the result, My heart was throbbing and mind full of contradictory thoughts……. yes,yes I was jumping after I heard the result, I finally made it.
and best part is that the profile I am being offered is Software Engineer(Engineering Production) which is entirely development(no QA )
Congrats to my fellow Yahoo selectees Akhil and Mukesh! Hope to have a nice time at Yahoo!!
Tomorrow(29th October) is my birthday and I could have never imagined a better gift

Algorithm to remove duplicates from a sorted array

int unique(int *array, int number)   //sorted array
{
int k = 0;
for (int i = 1; i < n; i++) {
if (a[k] != a[i]) {              //comparing the first 2 unequal numbers
a[k+1] = a[i];                 //shifting to the left if distinct
k++;
}
}
return (k+1);             //return the last index of new array i.e. the number of distinct elements
}

Algo to find duplicates in an array having elements in the range [1,n]

Algorithm 1

input[n]  //input array of size n, containing n  numbers

int output[n]; // Supporting array for our algo, initialized to 0
for(int i=0;i<n;i++)
output[input[i]]++;  //using elements of input array as index to create the o/p array

for(int i=0;i<n;i++)
{
if(output[i]==0)  // If the ith element is zero, it means i wasn’t present in input array

cout<<i; // display i
}

Algorithm 2 << My favourite

traverse the list for i= 1st to n+2 elements
{
check for sign of A[abs(A[i])] ;
if positive then
   make it negative by   A[abs(A[i])]=-A[abs(A[i])];
else  // i.e., A[abs(A[i])] is negative
   this   element (ith element of list) is a repetition
}

Reversing a singly linked list : Useful methods

Hi,
Yesterday I was thinking of different ways to reverse a linked list.Here are the best ones I worked on:

Assume the following structure definition:
struct llist
{
int data;
llist *next;
};

3 Pointer method(with decomposition):
llist * reverselist_3p(llist * start)
{
llist * current = start;     //Pointer 1: To store the current node
llist * nexttocurrent = NULL;  //Pointer 2: To store the node next to current
llist * temp = NULL;            //Pointer 3: To temporarily store node just detached from the main list, so that we can assign it to the ‘current’ in the next iteration
while(current!=NULL)
{
nexttocurrent = current->next;

current->next = temp;
temp = current;

current = nexttocurrent;
}
return temp;
}

3 Pointer method(without decomposition):
llist * reverselist_2p(llist * start)
{
llist * back = NULL;     //Pointer 1: To store the back node
llist * middle = start;            //Pointer 2: Middle node
llist * front = middle->next;        //Pointer 3: Front node
while(front!=NULL)
{
middle->next = back;
back = middle;
middle = front;
front = front->next;
}
middle->next=back;
return middle;
}

2-3 Pointer method (A beautiful Recursion) : # My favorite
llist * reverselist_re(llist * start)
{
if(start==NULL)
return NULL;
llist * first = start;
llist * rest = first->next;
if(rest==NULL)
return first;

start=reverselist_re(rest);  //you may argue that start is the 3rd pointer

first->next->next = first;
first->next = NULL;

return start;
}

If you like this post, please post you valuable comments.

Now Head, Web Management and Development, IEEE-DCE Student council

I am very glad today , I have been given the post of Head, Web Management and Development in my university branch of IEEE.I have been working for IEEE for nearly the last 2 years and today I feel extremely happy yet a bit emotional.
I remember the days when I was in first year at college, the only vibrant thing that I observed in my college was IEEE. Amazing workshops, amazing people and amazing skills. I always used to idolize my IEEE seniors then. Today I have become one of them.I hope I live upto the expectations of so many people.
Thanks to God for everything