By majk, 2 weeks ago, In English,

Hungry for yet another contest? On Sunday, October 7, 2018 at 17:05 UTC the Lyft Level 5 Challenge will start with the Round 1! This is a combined round having 7 problems and lasting 2 hours, and it will be rated.

The top 100 participants of this round will win a Lyft Level 5 Challenge t-shirt. The top 30 contestants located in the San Francisco Bay area will be invited to the Final Round.

In the Final Round the top three onsite contestants will fight for the cash prizes:

  • First place: $2000
  • Second place: $1000
  • Third place: $500

Interested in an internship or a job at Lyft?

Many thanks to:

I'll be on the community Discord server shortly after the contest to discuss the problems.

UPDATE 1: The scoring distribution will be 500-1000-1500-2250-2750-3250-4000.

UPDATE 2: The contest is over and there is an editorial.

UPDATE 3: Congratulations to the winners:

  1. tourist
  2. V--o_o--V
  3. CongLingDanPaiShang3k5
  4. Errichto
  5. 300iq

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By lyft, 5 weeks ago, In English,

We are thrilled to announce the Lyft Level 5 Challenge hosted by Codeforces and sponsored by Lyft. This international competition consists of two, timed rounds, where competitors will solve multiple algorithmic puzzles much like the ones we’re solving at Level 5, Lyft’s self-driving division.

Round 1: Elimination

On Sunday, October 7, 2018 at 10:00 PDT, the competition kicks off with a standard two-hour round of seven problems. The top 100 participants will win a Lyft Level 5 Challenge t-shirt. The top 30 contestants located in the San Francisco Bay area will be invited to Round 2.

Round 2: Final at Level 5

On Sunday, November 4, 2018 at 10:00 PST, round 2 kicks off with a standard two-hour round of five problems. Up to 30 contestants will compete for prizes at the Level 5 Engineering Center in Palo Alto, California, and Codeforces will host a parallel round for offsite participants. After the challenge, stick around for a Level 5 team social.

Round 2 Prizes

  • First place: $2000
  • Second place: $1000
  • Third place: $500

Terms and conditions apply.

About Level 5

Level 5 is Lyft’s self-driving division based in Palo Alto, California, and Munich, Germany, where we’re building a full self-driving system. Engineers at Level 5 are equipping vehicles with the latest advancements in sensors and applying deep learning to predict and perceive the world around us. We’re leveraging route by route data from the 10 million Lyft rides completed weekly to both rapidly advance our technology and train our vehicles.

Every member of our fast-moving, collaborative team has the opportunity to have an outsized influence on our self-driving development. And we’re passionate problem solvers, too. Meet Vladimir Iglovikov [kaggle], Viktor Barinov [cf, tc], and Alex Lapin [kaggle, cf, tc].

Help define the future of self-driving technology with us at Level 5. See our open roles at, and follow us on Twitter @LyftLevel5.

What is Lyft?

Lyft is the fastest growing ridesharing company in the United States with coverage for over 95% of Americans in all 50 states. We’re working toward our mission of improving people’s lives with the world’s best transportation.

Interested in an internship or a job at Lyft?

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By SYury, history, 2 weeks ago, In English,


Codeforces Round #514 (Div. 2) will start tomorrow, October 05, 17:35 (UTC+3). This round will be rated for the second division (with rating lower than 2100).

Many thanks to KAN for his help with the problems and round coordination, Aleks5d and Um_nik for testing this round, and MikeMirzayanov for his awesome Codeforces and Polygon platforms.

There will be 5 problems for 2 hours. The scoring distribution will be announced later.

UPD: the scoring distribution will be 500-1000-1500-2000-2500

UPD2: Congratulations to the winners!
Div. 2:
1. UoA_ZQC
2. PaidySung
3. Hyperbolic
4. thinfaifai
5. reku

Both divisions:
1. Radewoosh
2. UoA_ZQC
3. natsugiri
4. nuip
5. PaidySung

UPD3: editorial

Good luck!

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By Endagorion, history, 2 weeks ago, In English,

On Oct/04/2018 10:05 (Moscow time), the Codeforces Round #513 by Barcelona Bootcamp (rated, Div. 1 + Div. 2) will start. This is a special round for the Hello Barcelona Programming Bootcamp, in collaboration with Moscow Workshops ICPC. It is rated for all participants, everybody can register on it regardless of a rating.

Hello Barcelona Programming Bootcamp is sponsored by VTB and Indeed Tokyo, with the addition of team sponsors Phaze Ventures, Spark Labs and REMY Robotics.

VTB, the largest international bank based in Eastern Europe, continues to be an official partner of the Hello Programming Bootcamp series, adding further quality to the 3rd edition of the Hello Barcelona Programming Bootcamp by bringing their own participants, as well as by supporting top teams from around the world.

Indeed Tokyo is Japan's branch of the #1 employment website in the world, giving job seekers free access to millions of jobs from thousands of company websites and job boards. As they sponsor for the second year in a row, Indeed continues to offer the best job opportunities to the boot camp participants.

Wish good luck to all the participants!

There will be 8 problems, common for both division. Score distribution: 500 750 1250 1500 1750 2250 2750 3000.

The problems are prepared by me, Arterm and GlebsHP, with assistance from 300iq, ifsmirnov and gritukan. Have fun!

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By kostka, 3 weeks ago, In English,

Hey Codeforces!

I made a thing and I want to share it with the community.

We wanted to keep track of achievements and submissions in our team and using Codeforces status page is not really handy. Therefore, I introduce to you Team dashboard.

Here you can find some kind of a timeline for each member of your team, showing last submissions, contests and even blog posts on Codeforces.

Using this script is pretty easy, just specify up to 3 handles in the address, separated by semicolons (please check below). Also please keep in mind that this script was made in 3-4 hours, so there is almost certainly a handful of bugs. Also, the script asks a lot of queries to the Codeforces API, so sometimes not all requests are answered. You should wait a couple of seconds and try again.

Visit right now and bookmark your team:;Errichto;kostka

You can also compare yourself with your archenemy:;olekluka

Upd: fixed some bugs, including incorrect places and no response if no one from the team submitted anything.

Upd2: fixed bug with blocked blogs.

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By Laggy, history, 3 weeks ago, In English,

Hello beloved community, today I am happy to present you codeforce's contest picker which is a public version of our internal community's picker that can be read about here.

This is a continuation of CPC (Competitive Programming Community) project that you can check out in my older blogs.

What does it do?

It's simple, you add a list of handles and it will pick you all the contests that none of the handles had tried (submitted, not necessarily accepted) before.

Gym is now included:

Since ICPC is near, I decided to include gym contests since you guys probably want to do them with your teams? I hope I was right.

Normal rounds are also included:

Right at the top of the website you see Virtual Contest Picker.

Searching works.

Both Virtual Contests / Gym Pickers have a search bar that filters the list using some string. If you want to do past ACM regionals with your mates you can just type ACM in the search-bar and it will show you ... contests whose name contains ACM.. obviously.


1- Visit our website (below).

2- Choose your picker.

3- Add a list of handles.

4- Choose the contest.

5- Solve the contest.

6- Go to ICPC.

7- Beat Um_nik and his team.

Step 6 and 7 are optional. Jk, 1 to 5 are the optional.

Pick a Contest


Credits: Laggy BasselBakr

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By Errichto, 3 weeks ago, In English,

I want to try streaming competitive programming. The goal is to make it educational so I will be talking a lot, also answering (at least some) questions.

I'm planning three completely different streams to see what format to use:

  1. Solving random easy-medium problems.
  2. Solving old problems from Polish olympiad.
  3. Post-contest stream, assuming I'm a setter or tester of a contest. Similar to what scott_wu, ecnerwala and stevenkplus did.

Any thoughts, ideas?

The first stream will most likely be on Sunday, starting around 7-8pm CEST. I will use Twitch and talk in English only. These first streams should show me and you whether it's cool and useful, and whether I like doing it.

Also, I will try to make the video accessible later.

--- UPDATE ---

The first stream will start on Saturday at 10am CEST (check your timezone) here: I will solve some div1 A-C problems, not necessarily from Codeforces.

--- UPDATE 2 ---

The second stream on Sunday evening, with problems from POI 22, round 1. You can try to solve them yourself first — link. I will do problems from POI in a few days.

I will start today at 19:35 CEST (check your timezone) and I will talk about hard problems from this year TCO qualification rounds. If I do well in SRM today, I can start with problems from the round first. So, the main topic is hard DP problems, I guess. I prefer to stream on Youtube today, but I have some difficulties. I will announce here where the stream will happen. If someone has experience with Youtube live, please write to me.

I will stream on Youtube:

--- UPDATE 3 ---

SRM was moved by one hour, so my stream will start at 20:35 CEST.

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By KAN, 4 weeks ago, translation, In English,

Hi all!

This weekend, at Sep/23/2018 16:05 (Moscow time) we will hold Codeforces Round 512. It is based on problems of Technocup 2019 Elimination Round 1 that will be held at the same time.

Technocup is a major olympiad for Russian-speaking high-school students, so if you fall into this category, please register at Technocup 2019 website and take part in the Elimination Round.

Div. 1 and Div.2 editions are open and rated for everyone. Register and enjoy the contests!

The Elimination Round authors are Ajosteen, BledDest and adedalic. Thanks to FCB1234 who authored the last problem for div. 1 round and arsijo for his help in coordination. This round would also be not possible without the help of our testers: winger, Um_nik, AlexFetisov, Denisson, thank you so much!

Have fun!

Div. 2 and the Elimination Round will feature 7 problems, preliminary costs are
250 — 500 — 750 — 1500 — 2000 — 2500 — 3000.

Div. 1 will feature 5 problems, preliminary costs are 500 — 1000 — 1500 — 2000 — 2500.

The round is over, congratulations to the winners!

Technocup 2019 - Elimination Round 1

  1. 300iq
  2. antony191
  3. voidmax
  4. karasek
  5. ushakov.fedor

Codeforces Round #512 (Div. 1, based on Technocup 2019 Elimination Round 1)

  1. fjzzq2002
  2. mcfx
  3. yjq_naiive
  4. j_______________________
  5. volamtruyenkyii

Codeforces Round #512 (Div. 2, based on Technocup 2019 Elimination Round 1)

  1. Chair_man_Xi
  2. icecuber
  3. yp155136
  4. xjd0623
  5. liyingyan7

The analysis is published.

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By valkyrie, history, 5 weeks ago, In English,

Hello, Codeforces!

It's our pleasure to announce the the finals of the 11th Bubble Cup! Bubble Cup is a programming competition organized by Microsoft Development Center Serbia (MDCS). The contest will take place on Saturday, 22nd of September at 11:00 UTC+2 in Belgrade, and will last for 5 hours. Live results will be available on the official Bubble Cup website. Results will be frozen during the last hour of the competition. The winners will be announced at the closing ceremony.

The format of the competition is very similar to ACM-ICPC — teams consisting of up to three people are allowed, and they have one computer and five hours to solve problems without partial scoring. Ties are broken using the usual time penalty rules.

Just like in the previous years, there will be an online mirror of the finals here at Codeforces, starting on Saturday, 22nd of September at 12:35 UTC+2. Unlike in the previous years, the mirror will be on the same day as the onsite finals.

This year, the onsite competition is divided in two "divisions", called Premier League and Rising Stars. The two contests will have most of their problems in common, but the Rising Stars competition will feature some easier tasks targeted at high school contestants. We do not guarantee that every problems unique to Div2 is easier than every problem that is not.

Both of the contests will be mirrored here on Codeforces, with Premier League mapping to the Div1 contest and Rising Stars mapping to the Div2 contest. The mirror will use native Codeforces ACM-ICPC team contest rules.

Both contests will be unrated, due to the format and the length of the mirror being dissimilar to the standard Codeforces rated rounds. Note that this is a team contest, i.e. competing in teams up to three people is allowed. (Of course, you can also compete in a 1-person team.) There will be at least 9 problems in each division.

As of now, Codeforces does not support rating-based divisions in team contests, so we came with the following ad-hoc rule: teams with the maximum rated member having rating less than 1900 should enter the Div2 contest. Teams with the maximum rated member having rating at least 2100 should definitely enter the Div1 contest. The teams not covered by the previous two criteria are free to choose.

Here are the past Bubble Cup mirrors on Codeforces:

Bubble Cup 8 — Finals [Online Mirror]

Bubble Cup 9 — Finals [Online Mirror]

Bubble Cup X — Finals [Online Mirror]

The problems and their solutions were created by employees and interns of Microsoft: Milanin, ibra, balsa_knez, Kole, radras, fulu, pedja, niksmiljkovic, davidmilicevic97, FilipVesovic, yours truly, and many more. Most of the team works in MDCS.

We express gratitude to KAN and 300iq for round coordination, and MikeMirzayanov and the rest of the team for the great Codeforces and the wonderful Polygon platform. We thank testers DBradac and especially the extremely helpful knightL, for helping prevail various difficulties.

The full editorial, together with the statements and solutions of the tasks from the qualification rounds, will be available in the booklet section of the Bubble Cup website on Sunday. An editorial with short descriptions of solutions may appear on Codeforces before that.

Good luck to all participants!

EDIT: Congrats to everyone that competed! In total, there were over 800 teams that solved at least one problem.

The winners of Div1 are:

  1. Merkurev, I_love_Tanya_Romanova, Um_nik — a special congratulations for being the only team on the mirror to solve all problems, two of them in the last 5 minutes!

  2. LHiC — the best one-man team, with 9 problems solved

  3. Breakun, Hyunuk, ko_osaga — also solved 9 problems

The winning team of Div2 is:

  1. fengyecong, Als123, 200815147 — winning with three problems to spare!

This post will be updated again when the booklet is online, which should be before the end of the day in UTC+2. Also, onsite results won't be known until the awards ceremony in the evening.

Thanks all for participating!

EDIT 2: The editorial is up!

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