Vladithur's blog

By Vladithur, history, 5 months ago, In English

Hope you liked the problems! We apologize for the (very?) weak tests in H.

Editorials for problems will be added over time (and hints), for now, please take a look at the available hints and model solutions.

Easter eggs

1987A - Upload More RAM

Hints
Tutorial
Solution
Feedback

1987B - K-Sort

Hints
Tutorial
Solution
Feedback

1987C - Basil's Garden

Hints
Tutorial
Solution
Feedback

1987D - World is Mine

Hints
Tutorial
Solution
Feedback

1987E - Wonderful Tree!

Hints
Tutorial
Solution
Feedback

1987F1 - Interesting Problem (Easy Version) and 1987F2 - Interesting Problem (Hard Version)

Hints
Tutorial
Solution (F2)
Feedback (F1)
Feedback (F2)

1987G1 - Spinning Round (Easy Version)

Hints
Tutorial (by errorgorn)
Solution
Feedback

1987G2 - Spinning Round (Hard Version)

Hints
Tutorial
Solution
Feedback

1987H - Fumo Temple

Please try solving the problem with a deterministic solution :)

Hints
Tutorial
Solution
Feedback

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By Vladithur, 5 months ago, In English

EPIC

Hi, Codeforces!

We are pleased to invite you to EPIC Institute of Technology Round Summer 2024 (Div. 1 + Div. 2), which will be held on Jun/30/2024 17:35 (Moscow time). You will be given 8 problems, two of which are divided into two subtasks, and you will have 3 hours to solve them. The round will be rated for everyone.

At least one of the problems will be interactive, so please read the guide for interactive problems if you are not familiar with it.

We would like to thank:

We hope you'll like the problemset!

UPD: The score distribution is 250 — 750 — 1000 — 1500 — 1750 — (2000 — 500) — (3000 — 2000) — 5000

UPD2: Editorial

UPD3: Congratulations to the winners!

  1. Radewoosh
  2. ecnerwala
  3. tourist
  4. Benq
  5. gamegame
  6. ksun48
  7. maroonrk
  8. JoesSR_
  9. Maksim1744
  10. ugly2333

And now, a few words from today's sponsor!

About EPIC Institute of Technology

EPIC Institute of Technology is an innovative educational project, driven by the Deltix team under the EPAM Systems umbrella. As part of EPIC — EPAM Product Innovation Center, we aim to cultivate the brightest minds and prepare them for a future in cutting-edge technology projects.

Why EPIC:

EPIC Institute of Technology is an accelerator for the best talents. Our students will acquire hands-on experience in one of the selected major programs, all of which are highly demanded right now on top projects, together with the fundamental knowledge, so indispensable for real professionals. Successful graduates will have a unique chance to jumpstart their career on the most challenging and interesting EPAM projects worldwide. You will join the community of intelligent and driven individuals and have an honor to work with and learn from them.

Here are the answers to the most common questions:

How much does education cost?

EPIC Institute of Technology is completely free. There are no fees to register for exams, tuition fees or any other hidden liabilities. The only restriction for getting into EPIC Institute of Technology is age. You must be older than 18 years old to become a student.

How is the educational process organized?

Each program lasts exactly one year. The academic year consists of two semesters. Courses in the first semester are the same for all programs. Courses in the second semester depend on the selected major program.

During the semester, students complete homework assignments and take 2 exams—a midterm and a final. The final grade a student gets for each training course depends on the quality of completed assignments and participation in practical classes.

How will the classes be held?

Lectures will be pre-recorded and available for self-study. Practical classes will be held at the specified time according to the provided schedule. Also, students will have an access to a Discord server, where they can discuss topics of academic interest with teachers and other students.

In what language will I study?

All programs are in English.

How can I apply?

The admissions process is as follows:

  1. Fill out the form on the website.

  2. Take part in one of the entrance exams that will be held in our Codeforces group. You can also find past exam breakdowns there, which may help you in your preparation. Exam dates will be announced later, so stay tuned to the announcement channel and our LinkedIn group.

  3. If you successfully pass the exam, you will receive an invitation email.

What will happen after graduation?

All EPIC Institute of Technology graduates will get a diploma and the best students will be offered to join, either as an intern or a full-time position, one of the hot EPAM projects where skills acquired at EPIC Institute of Technology will be demanded.

Please visit our website to learn more about EPIC Institute of Technology and the available programs. If you have any questions, you can quickly ask them in our chat.

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By Vladithur, history, 16 months ago, In English

Hope you liked the problems!

1856A - Tales of a Sort

Hints
Tutorial
Solution
Feedback

1856B - Good Arrays

Hints
Tutorial
Solution
Feedback

1856C - To Become Max

Hints
Tutorial
Solution
Feedback

1856D - More Wrong

Hints
Tutorial
Solution
Feedback

1856E1 - PermuTree (easy version)

Hints
Tutorial
Solution
Feedback

1856E2 - PermuTree (hard version)

Hints
Tutorial
Solution
Feedback

UPD: Tutorial for E1 has been added.

UPD2: Tutorial for E2 has been added.

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By Vladithur, history, 16 months ago, In English
Hi, Codeforces!

Alexdat2000, Igorfardoc, and I are pleased to invite you to our Codeforces Round 890 (Div. 2) supported by Constructor Institute, which will be held on Aug/05/2023 17:35 (Moscow time). This round will be rated for participants with a rating lower than 2100.

We would like to thank:

You will be given 5 problems, one of which is divided into two subtasks, and you will have 2 hours to solve them.

One of the problems will be interactive, so please read the guide for interactive problems if you are not familiar with it.

The score distribution is 500 — 750 — 1250 — 2000 — (1500 — 1500)

UPD: Tutorial

UPD2: Congratulations to the winners!

Div. 2:

  1. AMDAM
  2. Aoi_Minoa
  3. baojiaopicua
  4. Valaki2
  5. JCY_

Div. 1:

  1. neal
  2. maspy
  3. A_G
  4. AmazingTalker_Frank
  5. heno239

We are thrilled to share some exciting news with you! We are teaming up with our partner, Constructor Institute in Schaffhausen, Switzerland, to bring you an amazing opportunity: a round supported and organized in collaboration with Constructor Institute, where you can explore Master's programs in Switzerland. Now we pass the floor to our partner.

CU

Hello, Codeforces community!

Constructor Institute in Schaffhausen (Switzerland) is pleased and proud to have the opportunity to support the round on Codeforces. We invite you to participate in it!

If you are passionate about studying in Switzerland and pursuing a Master’s degree, we encourage you to fill out the form to initiate the application process and scholarship interview. Our Institute representatives will be in touch with you to guide you through the next steps.

We offer two Master programs, both taught in English, with flexible duration of 1.5 or 2 years full-time:

Our Master's programs open doors to a world of opportunities. Many of our students have secured high-profile roles in multinational companies in Switzerland and across the globe. Additionally, our programs also serve as an excellent preparation for Ph.D. research in fields such as software engineering, cybersecurity, artificial intelligence, and other advanced topics.

​​We understand that financing your education can be a concern, and to support your journey, we are offering the following scholarships:

  • Tuition waiver scholarships — 20,000 CHF per year, covering the cost of tuition fees.
  • Full scholarships — 20,000 CHF per year, covering the cost of tuition fees, along with a monthly stipend of 2,000 CHF to assist with living expenses in Schaffhausen.

Both scholarships are non-repayable, providing you with financial peace of mind.

To learn more about Constructor Institute and its programs, visit our webpage.

Eligibility for the programs and its available scholarships:

  • You have obtained or you will obtain a Bachelor’s degree in Computer Science, Software Engineering, Physics, or a related field before the program starts.

To express your interest in this opportunity, please complete the form:

Complete the Form

We wish you good luck in the competition and enjoy solving the problems.

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By Vladithur, history, 23 months ago, In English

Hope you liked the problems!

(from thanhchauns2) Before the round starts

1768A - Greatest Convex

Author: thanhchauns2

Hints
Tutorial
Solution
Feedback

1768B - Quick Sort

Author: Vladithur Preparation: Vladithur and Alexdat2000

Hints
Tutorial
Solution
Feedback

1768C - Elemental Decompress

Author: thanhchauns2

Hints
Tutorial
Solution
Yet another better solution
Feedback

1768D - Lucky Permutation

Author: Vladithur Preparation: Vladithur and Alexdat2000

Hints
Tutorial
Solution
Feedback

1768E - Partial Sorting

Author: thanhchauns2

Hints
Tutorial
Solution
Feedback

1768F - Wonderful Jump

Author: Vladithur Preparation: Vladithur and Alexdat2000

Hints
Tutorial
Solution
Shorter solution (tfg)
Feedback

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By Vladithur, history, 2 years ago, In English

Thanks for participating in the round, we hope you liked the problems!

Solve count predictions (official div. 2)

1712A - Wonderful Permutation

Hint
Tutorial
Solution

Bonus: solve for every $$$k$$$ from $$$1$$$ to $$$n$$$ for $$$n \le 10^5$$$.

1712B - Woeful Permutation

Hints
Tutorial
Solution

Bonus: try to prove the solution without the editorial!

1712C - Sort Zero

Hints
Tutorial
Solution

Bonus: solve for when $$$a_i$$$ can also be negative.

1712D - Empty Graph

Hints
Tutorial
Solution

Bonus: solve for every $$$k$$$ from $$$1$$$ to $$$n$$$.

1712E2 - LCM Sum (hard version)

Hints
Tutorial
Solution

Bonus: solve the problem in $$$\mathcal{O}((n + t) \log n)$$$ or better.

1712F - Triameter

Hints
Tutorial
Solution

Bonus: solve for $$$n, q \le 10^6$$$.

Don't forget to rate the problems!

Problem Feedback

PS: Solution codes probably will be added later.

UPD: explanations of the references:

Click here

UPD2: added solution codes (better late than never...)

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By Vladithur, history, 2 years ago, In English
Hi, Codeforces!

Igorfardoc and I are pleased to invite you to our Codeforces Round 813 (Div. 2), which will be held on Aug/13/2022 17:35 (Moscow time). This round will be rated for participants with rating lower than 2100.

We would like to thank:

You will be served 6 problems, one of which is divided into two subtasks, and you will have 2 hours and 15 minutes to sample them.

Hope you don't choke 😋

The score distribution is 500 — 1000 — 1500 — 2000 — (2000 — 750) — 3500

PS

UPD: Tutorial

UPD2: Congratulations to the winners!

Div. 2:

  1. iztrax
  2. TrungNotChung
  3. Akemi-Homura
  4. bajablast
  5. __NONE__

Div. 1:

  1. tourist
  2. m_99
  3. jiangly
  4. LJC00118
  5. sjc061031

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By Vladithur, history, 3 years ago, In English

You can also find video editorials for problems B-D on ak2006's Youtube channel!

1632A — ABC

Hint 1
Hint 2
Solution
Solution codes

1632B — Roof Construction

Hint 1
Hint 2
Solution
Solution codes

1632C — Strange Test

Hint
Solution
Solution codes

1632D — New Year Concert

Hint 1
Hint 2
Hint 3
Solution
Solution codes

1632E2 — Distance Tree (hard version)

Hint 1
Hint 2
Hint 3
Hint 4
Solution
Solution codes

P. S. Solution codes will be published a little later.

P. P. S. Do not forget to evaluate the problems in the announcement.

UPD: Solution codes have been posted.

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