Project Ideas

Very little guidance in my current project. It seems like I have been dropped into an ocean when I was still making myself comfortable in a swimming pool. I have a very large data set approximately 9x10^8 entries and as each of them is a 64 bit double it takes up a lot of space = 7.2 GB, it is impossible to fit into the memory given all the other variables that I want to store. I tried using float but that gave me strange results.

Another concern is that the data is very sparse. In a matrix of size 9million X 3 million, I have only 14 million non zero entries, now most of the rows have nearly one or 2 non zero entries.  On an average every row has less than 2 non zero entries. Need to think

Project Ideas : Old and new

1. Application to aggregate donations for humanitarian cause
2. Matter: Crowd sourced news platform
3. 

Another problem unsolved

Couldn't solve this problem...feeling disappointed :(

Some puzzles

Sometimes I feel I am so dumb that I should not be allowed to solve puzzles. I spent the complete day today to figure out my mistake in this simple problem on codechef june long contest. I figured out the solution in first 10 minutes but was handling a simple corner case in the wrong way. The worst part is I tested my code on the corner case multiple times and overlooked the error. What a dumbass I have turned out to be. Any way, I am still not able to figure out the solution to the next problem.

Dheeraj Baba also told me some puzzles today...I will mention them here and think about them.
1) One based on the famous handshaking lemma: In a party there are 5 couples including the host. Every person in the party shakes hand with every person he doesnt know. At the end of the party the male host announces that he asked every one the number of hands the shook and everyone gave a different answer. How many hands did the female host shook? The host mayn't know everyone they invited.

2) Given a tree, find the two vertex which are maximum distance apart?
3) What is the minimum number of coins of giver denomination required to make a sum of N? see this
4) Number of possible configurations of a rubic's cube?