Tuesday, November 21, 2017

Updates from last 3 weeks or so...

I took part in Codechef's November Challenge (which stretched from 3rd till 13th of Nov.) intermittently solving some of the tough problems (not necessarily quickly) to keep a track of my progress and increase my comfort in solving problems in a long contest setting.

Ranked at 2856 out of 7024 who submitted at-least one problem partially or completely correct, I'd say it was an slight better than average performance. My long-contest rating saw a big boost, but I simultaneously saw a drop in my overall codechef rating [performance graphs]. Solved 3 problems successfully, tried fourth and fifth one but couldn't figure out the problem so didn't attempt and saw wrong answer for a submission for the sixth problem. For the remaining four, I didn't even get a chance to go through given the limited time I had (this happens when you manage your job while stealing some time out for your hobby. ;) )

Successful submissions are open to public post closure of the contest:

I am yet to up-solve those 7 problems which I couldn't solve during the contest.


The following week, I got my free time busy with the 35th Week of Code by Hackerrank.
Ranked at 3181 out of 9289, I'd say I performed better than average among the participants but there is still a huge gap between my score (59) and that of the highest scorer (290).

Here, I solved the first 3 problems successfully.

The fourth problem, Matrix Land, was a show-stopper! I really recommend it! I spend 3 evenings on it and still was not able to come up with a working solution. I was trying to figure out a modification of Bellman-Ford algorithm (which is a Dynamic Programming algorithm) to solve it with some decent efficiency but was getting nowhere as there was no way to mark visited vertices...
It turns out, reading the insightful problem editorial, one could solve it using a bunch of dynamic programming equations.

I went through the 5th and 6th problems too which were number crunching problems and they despite of being hard and expert level, seemed easier than the 4th one but didn't get much time to think them through their solutions.

Again, I have yet to up-solve the unsolved ones.