### hmehta's blog

By hmehta, history, 8 months ago,

Hey All!

Topcoder SRM 779 is scheduled to start at 11:00 UTC -5, Feb 21, 2020. Registration is now open in the Web Arena or Applet and will close 5 minutes before the match begins.

Thanks to misof and lazy_fox (CF:mridul1809) for writing the problems and coordinating the round.

This is the sixth SRM of Stage 2 of TCO20 Algorithm Tournament and TCO20 Regional Events Qualification

Match Results (To access match results, rating changes, challenges, failure test cases)
Problem Archive (Top access previous problems with their categories and success rates)
Problem Writing (To access everything related to problem writing at Topcoder)
Algorithm Rankings (To access Algorithm Rankings)
Editorials (To access recent Editorials)

Good luck to everyone!

• +3

 » 8 months ago, # |   +1 Problem Writing page seems to be not working.
•  » » 8 months ago, # ^ |   0 The link has been updated: https://www.topcoder.com/thrive/articles/Write%20Problems%20for%20Topcoder(All the old editorials, tutorials are being moved to our new content portal — Thrive. The movement is in progress. My bad — I did not update in the text here.
 » 8 months ago, # | ← Rev. 3 →   0 I am still not able to subscribe to your newsletter.https://codeforces.com/blog/entry/73920#comment-580920
•  » » 8 months ago, # ^ |   0 Hey! It is working fine. I tested for a few accounts. Let me DM you and we will investigate more.
 » 8 months ago, # |   +33 Why you do this TC ?(I'd swap atcoder with CF though)
•  » » 8 months ago, # ^ |   +4 I'd swap CF with CSAcademy
•  » » » 8 months ago, # ^ |   +35
•  » » 8 months ago, # ^ |   -7 Where is leetcode? :)
•  » » » 8 months ago, # ^ |   +5 No of fks leetcode gives to CP = No of fks this meme gives to leetcode. :)
 » 8 months ago, # |   0 Auto comment: topic has been updated by hmehta (previous revision, new revision, compare).
 » 8 months ago, # |   0 Gentle Reminder: The match begins in 15 mins.
 » 8 months ago, # |   0 I saw that the statement to problem ArraySorting was updated, but i refreshed my page (2 times) and dont see nothing, so i just submitted the problem considering that the values range from 1...1000, and just now (in the end) realized that the values ranges from 1...2000, thats when i closed and reopened the problem right in the end of the contest :(
•  » » 8 months ago, # ^ | ← Rev. 3 →   -36 I was wrong before. The size of dp table is dependant on the range of values.
•  » » » 8 months ago, # ^ |   +31 One my friend though that original numbers are in range $[1, 2000]$ but we can only change to $[1, 1000]$. This matters cause this gives incorrect answer for $[2000, 2000, 1000]$, for example.
•  » » » 8 months ago, # ^ |   +10 It does. In the old statement if the values are 1-1000 then you can make tests like 1997 2000 1999. You can use 1 step in the new version but not in the old version.I made this mistake too and solved on the old statement :) didn't notice the announcement
 » 8 months ago, # |   +13 Completely unrelated to this SRM, but I noticed that the (Java) arena doesn't update everything when it's sufficiently out of focus — when I'm on desktop 2 and the arena is on desktop 1, then: when systests in practice finish, it shows the last state I saw before they finished when a new phase starts, the timer updates, but the name of the phase (e.g. CODING) doesn't I'm sure there are other cases. I can understand why it's done this way (to save bandwidth when I'm not using the arena), but it's objectively inferior to the purely client-side approach with server-side validation.
 » 8 months ago, # | ← Rev. 2 →   0 How to solve SubstringQueries?
 » 8 months ago, # |   +2 Will there be any recalculation of the scores? I see some people had to resubmit and some even didn't and their problems fell because of that (for example I managed to challenge dreamoon's solution which looked at up to 1000). Although I did rather well, I don't think that's fair.
•  » » 8 months ago, # ^ |   +11 But there was an announcement in Applet (not sure about web arena though).
•  » » » 8 months ago, # ^ |   0 Sure, but what if you submitted before the announcement?
 » 8 months ago, # |   +1 For OneGCD problem how is answer phi(y[i])
•  » » 8 months ago, # ^ |   0 Read D's soln. Same problems. https://codeforces.com/blog/entry/73467
•  » » 8 months ago, # ^ |   +1 Main observation is that, given some positive integer $m$, any interval of $m-1$ consecutive integers has same number of numbers coprime to $m$. So, you can just count the number of numbers coprime to $m$ that are in $[0,m-1]$, which is exactly $phi(m)$.