Tuesday, August 30, 2016

Things perfect with Codeforces

Perfect with codeforces:

1. Robust UI with no fancy css or hanging elements or moving elements.
2. Friends Raning is great
3. Sort solutions to a problem in practice area or contest by execution time, size.
4. Can message some user.
5. You can see friends rating changes.
6. Can easily see test cases that failed (partial test case in case it is very huge)

Things fixed in codeforces that topcoder lacks

1. Easy navigation from problem to rankings, solutions, self-submissions.
2. Easy navigation to editorials.
3. Easy navigation to discussion forum.
All above 3 points are pain-full in TopCoders. And TC doesn't release editorials for many SRMs and which are released are so late, that you forget the problem.
4. Lightweight UI. Any page of codeforces doesn't take more than 45 MB on my ubuntu 32bit machine in firefox. The webarena of TC is not yet fully in working condition. And I think they have just made it even harder to navigate, given the heavy elements in the browser arena.

Things wrong with Hackerrank w.r.t competitive coding

1. Leader board consists of only scores. Even if I unlocked the solution, I can't search for specific user to see his solution.
You can go to problem-wise leader board, but then that is sorted by submission time and not with total highest score. So, if i wanted to search how a user A, solved problem X, I can't do it easily.

2. Doesn't remember the search key used in filter, nor shows previously searched keys as drop-down. Each time I have to type a college name and few colleges have different entries in their database as student entered it as per their convenience example III H, IIIT Hyderabad and International Institute Of Information Technology. All are same college, but needs to be searched differently. And hence we don't see a common college leaderboard either.

3. You can't rate editorials. Some problems have great editorials but we can't rate them.

4. No comment section on editorials

5. Author and Tester should get back on editorial if people have further questions about their editorial

6. One of the biggest drawback, Hackerrank loves to keep lot of free space in the UI. They should try to shrink it a little bit. Once a page loads, half of the screen is taken up by menu, problem name in very big font, and another big tabbed-menu.

7. They have a irc channel http://webchat.freenode.net/?channels=hackerrank, but it's a ghost town. No easy way to give feedback and even if it read sometimes by any mods in discussion forum, you find them less enthusiastic to talk about it.

Sunday, August 28, 2016

Google Apac 2017 Round B Problem A "Sherlock and parentheses"

The problem was to find maximum number of substrings of L left brackets and R right brackets that are balanced. The first thing we can see is that, the number of balanced substrings will be maximized only when the left and right appear in pair, without any nesting. .i.e.

Quick Compilation of bits/stdc++.h header for competitive coding

If you are using bits/stdc++.h header to include all the header files at once, then probably you are also facing compilation time of about 8 to 10 seconds. This compilation time is long during contest, as you need to get the output fast to go with the Read-Eval-Print-Loop( REPL ) approach, and it can be frustrating at times.

Wednesday, August 24, 2016

All tagnames in nltk

We can display all the tagname along with the definitions/usages right at the python prompt.

Friday, August 19, 2016

List of competitive programming websites/OJ

There are several Online-Judges(OJs) and Competitive Programming websites on the Internet, here are few we are active on