how many words per minute you type?
how many words per minute you type?
Hi guys! Today I had an exam on algorithms and data structures, where one of the tasks was to write down an algo for finding longest common increasing subsequence in $$$O(n^2)$$$ (yeah, using pen and paper...) For whatever reason, I came up with only $$$O(n^2logn)$$$ solution. However, this solution could be easily simplified to $$$O(n^2)$$$ and many students from my course wrote this algorithm. I guess it happened because when you don't know segtree it is much easier to avoid wrong paths and reach good solution.
Then I caught myself on the thought that in many problems before I also implemented very dumb overkilled solutions with segment tree simply because I know this data structure (thank god I don't know treaps that well). Then I came up with the name of this phenomenon: "The Curse of Segment Tree". So I wonder have anybody also stumbled with this "curse"? (or I am the only orange guy who cannot come up with stupid dp on the uni exam TᴖT)
Sorry for the delay in publishing the editorial. If anything is unclear or missing, please let me know in the comments.
In all the problems, reading the hints is a must as the solution continues from there.
Idea: Dominater069
Preparation: Dominater069
Editorial: Dominater069
Idea : satyam343
Preparation : satyam343
Editorial : Dominater069
Idea : Dominater069
Preparation : Dominater069
Editorial : Dominater069
1943B - Non-Palindromic Substring
Idea : errorgorn, Dominater069
Preparation : Dominater069
Editorial : Dominater069
Idea: Everule
Preparation: Dominater069
Editorial: Dominater069
1943D1 - Counting Is Fun (Easy Version)
Idea : satyam343
Preparation : satyam343
Editorial : Dominater069
1943D2 - Counting Is Fun (Hard Version)
Idea : satyam343
Preparation : satyam343
Editorial : Dominater069
1943E1 - MEX Game 2 (Easy Version)
Idea: Dominater069
Preparation: Dominater069
Editorial: Dominater069
1943E2 - MEX Game 2 (Hard Version)
Idea: Dominater069
Solution : ffao
Preparation: Dominater069
Editorial: errorgorn
1943F - Minimum Hamming Distance
Idea: satyam343
Preparation: satyam343
Editorial: satyam343
During Codeforces Round 934 (Div. 2) I submitted problem D hoping to get the green AC but unfortunately got the red WA (submission 251770538). I spent the rest of the time in the contest trying to figure out the problem in vain. After the contest, I checked the accepted solutions and found that they were exactly like mine which made me more confused.
I stress-tested my solution using a brute-force approach during the contest and using AC solutions after the contest time but couldn't find a single test case. Even after a million random test cases, my solution is still steadfast. I know that a few hundred test cases are enough.
My implementation of string hashing is inspired by Usaco.guide, which uses random bases and a fixed modulus (1LL << 61) -1
). I used multiple bases to make sure no collisions happen, but this also didn't help.
Unfortunately, I couldn't get AC during the contest but now I'm curious about this weird behavior of string hashing. Why using many random bases doesn't help and the solution is to use a prime modulus (i.e. $$$10^9 + 7$$$)?
Now the situation is more complex, I tried to submit a solution (submission 252010026) with only one base and $$$10^9 + 7$$$ as a modulus and got AC. Isn't the collision probability high for such a case?
Another thing to note is the inability to use GNU C++20 compiler caused all of this chaos because I couldn't use __int128
and (1LL << 61) - 1
as a modulus which I think will get AC.
We will hold AtCoder Regular Contest 174.
The point values will be 300-300-500-500-700-900.
We are looking forward to your participation!
We are pleased to invite you to participate in Codeforces Round 936 (Div. 2), which will start on Thursday, March 21, 2024 at 17:35.
The round was prepared by exhausted, max0000561, azureglow and myself.
This round will be rated for participants whose rating is below 2100. Participants with higher ratings may participate out of the competition.
You will be given 6 problems and 2 hours to solve them. We hope you find them interesting.
We would like to thank:
Special thanks to KoT_OsKaR and teraqqq for their help in creating tasks.
Good luck on the round and high rankings to everyone!
Score Distribution: 500−1000−1500−1750−2250−2750.
Anyone has some advice for practice? Sometimes I can solve difficulty up to 2400 but sometimes can't.
upd: Can anyone suggest some difficult and important algorithm that a GM needs to learn?
Hello everyone, we are happy to announce the 2nd Universal Cup Semifinal and the 2024 Universal Cup Summer Summit.
In Season 2, thanks to everyone's support and efforts from our staff, there was a lot of progress compared to Season 1. We have over 3000 teams registered and so far we have scheduled over 30 stages in this season. We also managed to implement a registration webpage and host all kinds of contests on our platform, including the run-twice contest, the prime contest and the challenge contest. We also reached many agreements with Huawei about future cooperation, including the most exciting part: the onsite final. (Cooperation between Universal Cup and Huawei)
In the 2024 ICPC Latin American Championship, Universal Cup was invited to run the Huawei Challenge as a major part of the event. Our co-president Jingbang also gave a brief introduction of Universal Cup during the event to all the participants and coaches.
We still have more things coming! We have just finalized the rules for selecting the 2nd Universal Cup Final teams. There will be 20 slots for the event and the rule will be specified later. In addition, we have decided to host a special event, the 2024 Universal Cup Summer Summit in June. Supported by Huawei, we plan on inviting 10 teams to the wonderful city of Cancun, Mexico. The event will last around 5 days, including an onsite competition using the semi-final contest, a city tour, and some other activities. All fees will be covered by us. The exact schedule will be announced soon.
We want to express our gratitude again to everyone, especially problem-setters who have shared their wonderful contests with us. We are also planning to design souvenirs and prizes which will go to our contributors and participants, so stay tuned!
Here are the rules for the semifinal and the summer summit.
Universal Cup
2024.3.19
What's up competitive programmers :> !
Welcome, to another installment of CP TITANS! Get ready to unleash your coding skills as we present to you CP TITANS 5.O : The Code Heist. Organized by the Developers & Coders Club, NIT Agartala, this contest promises an electrifying experience filled with thrilling challenges.
Contest Details
Date: March 19th, 2024
Time: 9:00 PM — 11:00 PM, IST (+5:30 GMT)
Penalty: 10 minutes for each wrong submission
You will be offered 6 problems and 2 hours to solve them! We tried to make interesting, beautiful, problems with strong pretests. Contest will follow ICPC guidelines.
We would like to thank :
Raj Raj_Tiwari Tiwari, Vedant vedant_vaidya_77 Vaidya for helping and proposing problems :3
Chetan chetan_saini Saini, Tejas wintersoldier2004 Jha, Kavi kavi_khalique Khalique, Payal li_ght Singh for testing. :>
MikeMirzayanov and the entire Codeforces team for creating the wonderful platforms Codeforces and Polygon <3
Contest Link: Click on the below link to take part in the contest. Registration for the contest will start 6 hours before the contest. CP TITANS 5.0 : The Code Heist
About CP TITANS
CP TITANS is a prestigious coding competition organized by the Developers & Coders Club at NIT Agartala. With each edition, we strive to push the boundaries of innovation and excellence in the field of competitive programming. Join us as we embark on another thrilling adventure filled with coding challenges. For more information about Developers and Coders Club, NIT Agartala and updates regarding the contest, follow us on:
Mark your calendars and gear up for an unforgettable coding experience at CP TITANS 5: The Code Heist. See you all on March 19th! :)
Hello MikeMirzayanov,
In Codeforces Round 934 (Div. 2), as per the common standings my rank is 1192. However in the contests page my rank is 4811, as a result of which I got a rating change of negative 106. Please address my problem. standings
Proofs are attached below