pashka's blog

By pashka, history, 4 months ago, In English

Hello! On Feb/18/2024 15:05 (Moscow time) will start Codeforces Round 927 (Div. 3), the next Codeforces round for the third division.

The round is based on problems from JetBrains Academy Youth Challenge. If you participated in it, please don't participate in this round.

Problems for this round are prepared by denk, step_by_step, goncharovmike, ikrpprppp, pashka, Vladosiya and MikeMirzayanov.

Thank you very much awoo, BledDest, buyolitsez, EgorUlin, Gojova, GrandFruit, Hello_zoka, petyb, scanhex, senjougaharin, shnirelman, SomethingNew, Toy_mouse, Zandler for testing the round.

As usual for the third division rounds:

  • there will be 6-8 tasks in a round
  • round duration is 2 hours 15 minutes
  • the round follows the ICPC rules, penalty for an incorrect submission is 10 minutes
  • round is rated for participants with ratings up to 1600
  • after the round there will be a 12-hour open hacking phase

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behaviour. To qualify as a trusted participant of the third division, you must:

  • take part in at least five rated rounds (and solve at least one problem in each of them)
  • do not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

Good luck to all!

UPD: Editorial

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By pashka, history, 5 months ago, In English

1921A - Square

Idea: goncharovmike, prepared: pashka

Tutorial
Solution

1921B - Arranging Cats

Idea: pashka, prepared: ikrpprppp

Tutorial
Solution

1921C - Sending Messages

Idea: step_by_step, prepared: step_by_step, Vladosiya

Tutorial
Solution

1921D - Very Different Array

Idea: Vitaly503, prepared: pashka

Tutorial
Solution

1921E - Eat the Chip

Idea: ikrpprppp, prepared: ikrpprppp

Tutorial
Solution

1921F - Sum of Progression

Idea: Vitaly503, prepared: Vitaly503

Tutorial
Solution

1921G - Mischievous Shooter

Idea: Vitaly503, prepared: goncharovmike

Tutorial
Solution

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By pashka, history, 5 months ago, translation, In English

Hello! On Jan/15/2024 17:35 (Moscow time) will start Codeforces Round 920 (Div. 3), the next Codeforces round for the third division.

The round was coordinated by Vladosiya, and prepared by me and the students of Neapolis University Pafos: Vitaly503, goncharovmike, ikrpprppp, step_by_step.

Thank you very much Alexdat2000, dan_dolmatov, fastmath, FBI, Nickir, nikhil97agra, pavlekn, PMiguelez, SashaT9, senjougaharin, Sergey140146659, Sparrow_Guo, Toy_mouse, vladmart for testing the round.

As usual for the third division rounds:

  • there will be 6-8 tasks in a round
  • round duration is 2 hours 15 minutes
  • the round follows the ICPC rules, penalty for an incorrect submission is 10 minutes
  • round is rated for participants with ratings up to 1600
  • after the round there will be a 12-hour open hacking phase

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behaviour. To qualify as a trusted participant of the third division, you must:

  • take part in at least five rated rounds (and solve at least one problem in each of them)
  • do not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

Good luck to all!

UPD: Editorial

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By pashka, history, 2 years ago, In English

Here are the home tasks for the lecture, you can submit your solutions into this form.

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By pashka, history, 2 years ago, In English

Hello Codeforces!

The final semester starts this week! As usual, the live lectures will be on Twitch on Fridays at 18:00 MSK, and the recorded videos will be on Youtube.

Topics of the fourth semester:

  • Matchings
    • Bipartite Matching
    • Non-bipartite Matching (blossoms)
    • Assignment Problem
  • Network Flows
    • Maximal Flow
    • Minimal Cost Flow
    • Skew-Symmetric Flows
  • Linear Programming
  • Fast Fourier Transformation
  • Plus something more :)

See you!

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By pashka, history, 2 years ago, In English

The last lecture will be tomorrow at 14:00 MSK

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By pashka, history, 3 years ago, In English
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By pashka, history, 3 years ago, In English

Here are the home tasks for the lecture, you can submit your solutions into this form.

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By pashka, history, 3 years ago, In English

Here are the home tasks for the lecture, you can submit your solutions into this form.

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By pashka, history, 3 years ago, In English

Here are the home tasks for the lecture, you can submit your solutions into this form.

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form.

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

This week the lecture will be on Wednesday at 6pm MSK

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By pashka, history, 3 years ago, In English

Hello Codeforces!

The third semester starts this week! As usual, the live lectures will be on Twitch on Fridays at 18:00 MSK, and the recorded videos will be on Youtube.

Topics of the third semester:

  • Graph Algorithms
    • DFS and its applications
    • MST
    • Shortest Paths
    • Games on Graphs
  • String Algorithms
    • Substring Search
    • Suffix Trees
  • Plus something more :)

See you!

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form.

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form.

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form.

Tomorrow the lecture will be 1 hour earlier than usual, at 5pm MSK

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form.

See you next week!

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Last week I forgot to make the home tasks, please send me the message if this happens again.

Here are the home tasks for the lecture, you can submit your solutions into this form.

See you next week!

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form.

See you on Friday!

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form.

Last week home task discussion will be on Sunday at 17:00 MSK.

See you tomorrow!

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By pashka, history, 3 years ago, In English

Here is the video of the lecture. Thanks to everyone who watched the live stream.

Here are the home tasks for the lecture, you can submit your solutions into this form. Sorry for delay :)

See you tomorrow!

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By pashka, history, 3 years ago, In English

Hello Codeforces!

The second semester starts next week! As usual, the live lectures will be on Twitch on Fridays at 18:00 MSK, and the recorded videos will be on Youtube.

Topics of the second semester:

  • Segment Trees and similar data structures
    • Segment Tree
    • Fenwick Tree
    • Sparse Table
    • 2D Trees
  • Binary Search Trees
    • AVL Tree
    • Treap
    • Splay Tree
  • Data Structures for Trees
    • Binary Lifting
    • LCA and LA problems
    • Heavy-Light Decomposition
    • Link-Cut Tree
    • Centroid Decomposition
  • Plus something more :)

See you!

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