### Information

[How to get an account / participate in contests?](http://atcoder.jp/post/2) [AtCoder's Contest Format](http://atcoder.jp/post/1) [AtCoder's Testcases](https://www.dropbox.com/sh/arnpe0ef5wds8cv/AAAk_SECQ2Nc6SVGii3rHX6Fa?dl=0) - [AtCoder's Rating System](https://www.dropbox.com/sh/zpgcogxmmu84rr8/AADcw6o7M9tJFDgtpqEQQ46Ua?dl=0) - [AtCoder Race Ranking](https://docs.google.com/spreadsheets/d/1T-hKu_vIh8l4EiW6XTWOvP0evzsWj0f45JNNgou21Cc/edit#gid=695896678)

### Announcement for beta version

We provide [beta version](https://beta.atcoder.jp/). Several functions has been added. Please try it!

### AtCoder Rating System

posted:
The ratings were updated last Sunday, but it turned out that in the old rating system the ratings changed too much in a single contest. We changed the rating formula to fix this issue, and now the rating is calculated based on the new system. In AtCoder, when you participate in only a few contests your rating is much lower than your actual strength (so don't worry even if your current rating is very low). You need to participate in at least 10 contests in order to get accurate rating. We will publish the rating formula in the near future. Here is the table of colors: |Rating|Color| |:--:|:--:| |3600-3999|???| |3200-3599|???| |2800-3199|<span class="user-red">Red</span>| |2400-2799|<span class="user-orange">Orange</span>| |2000-2399|<span class="user-yellow">Yellow</span>| |1600-1999|<span class="user-blue">Blue</span>| |1200-1599|<span class="user-cyan">Cyan</span>| |800-1199|<span class="user-green">Green</span>| |400-799|<span class="user-brown">Brown</span>| |0-399|<span class="user-gray">Gray</span>|

### AtCoder Regular Contest 058 / Beginner Contest 042 Announcement

posted:
Two contests [AtCoder Regular Contest 058](https://arc058.contest.atcoder.jp/) and [AtCoder Beginner Contest 042](https://abc042.contest.atcoder.jp/) will be held on this Saturday at the same time. You can participate in whichever contest you want. (However, you can't register to both competitions.) The last two tasks in ABC are the same as the first two tasks in ARC. ABC is significantly easier than Div2 contest in TopCoder of Codeforces. If you can enjoy Div2 contests in TC or CF, I recommend you to participate in ARC. - Time： July 23rd (Saturday), [21:00 JST](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20160723T2100&p1=248) - Duration: 100 minutes - Number of Tasks: 4 - Writer：<a href="/user/yosupo" class="username"><span class="user-yellow">yosupo</span></a>, <a href="/user/kyuridenamida" class="username"><span class="user-green">kyuridenamida</span></a> - Rating： ARC is rated for those who have rating < 2800. ABC is rated for those who have rating < 1200. (However, note that current rating is much lower than your actual strength - if you are green or brown, I recommend you to choose ARC.) The point values are: - ARC: 300 - 400 - 700 - 1500 - ABC: 100 - 200 - 300 - 400 You can check the relation between point values and difficulties [here](https://agc001.contest.atcoder.jp/). We are looking forward to your participation! **UPD:** Thank you for participation! **UPD:** Ratings are updated.

### AtCoder Grand Contest 001 Announcement

posted:
The first international contest, [AtCoder Grand Contest 001](https://agc001.contest.atcoder.jp/), will be held on Saturday. - Time: July 16th (Saturday), [21:00 JST](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20160716T2100&p1=248) - Duration: <font color="red">110</font> minutes - Number of Tasks: 6 - Writer: <a href="/user/snuke" class="username"><span class="user-unrated">snuke</span></a> - Rated: Yes Each task is assigned a point value. For example, if you solve a 100-point problem correctly, you will get 100 points. Your solution will be judged soon after your submission (like ICPC). The contestants are ranked by the total scores. In case of tie, they are ranked by the penalties. The penalty is computed as (the time you spent to get current score) plus (5 minutes) * (the number of incorrect attempts). We are looking forward to your participation! The point values are 200, 500 (300 for partial task), 600, 1000, 1400, 2000. **UPD:** The editorial is uploaded. [editorial link](https://agc001.contest.atcoder.jp/data/agc/001/editorial.pdf) (English is at the bottom) **UPD:** Ratings are updated! **UPD:** The contest winners were: 1. <a href="/user/cgy4ever" class="username"><span class="user-red">cgy4ever</span></a> 2. <a href="/user/DEGwer" class="username"><span class="user-red">DEGwer</span></a> 3. <a href="/user/Um_nik" class="username"><span class="user-red">Um_nik</span></a> 4. <a href="/user/yosupo" class="username"><span class="user-orange">yosupo</span></a> 5. <a href="/user/jcvb" class="username"><span class="user-orange">jcvb</span></a> Congratulations! You can see the statistics [here](https://agc001.contest.atcoder.jp/statistics). In AGC 001, 949 coders participated from 53 countries. Here is the list of countries with at least 5 participants: - Japan: 703 - India: 83 - China: 33 - Russia: 23 - Bangladesh: 22 - Afghanistan: 13 - Iran: 12 - United States: 12 - Ukraine: 10 - Vietnam: 10 - Belarus: 8 - Poland: 7 - Taiwan: 7 - Egypt: 5

### How to get an account / participate in contests?

posted:
#### How to get an account? 1. Click "Sign up" at the top-right corner . 2. Fill your information and click "Sign up". User ID is your handle used in this website. It should consist of letters, digits, and underscores, and the length should be between 3 and 16, inclusive. User name is currently not used, but we recommend to fill it with the same string as User ID. 3. Click "Sign up" (blue button). #### How to recover the password? 1. Go to https://practice.contest.atcoder.jp/password/recovery. 2. Fill your User ID and email address, and click the blue button. 3. Now you received an email with title "[AtCoder]パスワード再発行の案内". (Unfortunately the email is written in Japanese - we will fix it.) 4. Click the link in the email. 5. Type your new password twice and click the blue button. 6. Now you can use your new password. #### How to participate in contests? 1. Go to the contest website. For example, if you want to participate in AGC 001, click "AtCoder Grand Contest 001" in "Upcoming Contests" box. 2. Now you are in http://agc001.contest.atcoder.jp/. 3. Click "Join in AtCoder Grand Contest 001". (You can do this during the contest, but we recommend you to do it before the contest to save your time. Your rating will not change if you don't submit anything during the contest.) 4. When the contest starts, go to the contest website and solve problems! 5. You can practice the usage of this judge at http://practice.contest.atcoder.jp/.

### Welcome to AtCoder!

posted:
Hello! I'm <a href="/user/rng_58" class="username"><span class="user-admin">rng_58</span></a>. I'm the contest manager in AtCoder. AtCoder is a programming contest website based in Japan. From this weekend, we will provide problem statements in both English and Japanese and AtCoder will be an international programming competition! There are three types of official contests in AtCoder: - AtCoder Grand Contest (AGC). This is our best contest. The problems will have high originality and require interesting observations. - AtCoder Regular Contest (ARC). The problems may be a bit typical compared to AGC problems, but still we think most of you can enjoy them and they are good for practice. - AtCoder Beginner Contest (ABC). This is mainly targeted for those who are new to competitive programming. The problems will be easy and educational. Usually, our contests will be held at 21:00 (JST) on Saturday. We are planning to hold AGC about twice a month, and in other weeks we will hold both ARC and ABC (you can choose in which contest to participate). We have a rating system and users will be colored according to their rating. There are eight colors in total (except for newcomers' black and admins' purple). Can you guess what colors are used? We hope you will enjoy AtCoder Contests!