Hello, codeforces!

Today, I introduce yet another online judge, Library-Checker!

As the name suggests, the object of this site is checking your libraries. The problems are "Implement RMQ", "Enumerate Primes", "Exp of Formal Power Series", "Decompose a graph into three-connected components"... and so on.

All problems are managed by me. In other words, I'm the admin of this site.

Anything of problems (testcases, solutions, generator, ...) are managed in github. It means,

• Anyone can add problems add testcases. Already most of the problems are prepared by other competitive programmers.
• Testcases are stronger and stronger with time (ideally).

Let's enjoy your library maintenace!

(For competitive programmers who can do "real" programming: Have you ever think that "I want to test my library in CI..."? This judge will achieve your hope! Please refer verification-helper)

Hello Codeforces!

On 16th September Japan Alumni Group Summer Camp 2018 Day 2 Contest will take place on AtCoder Contest link(You cannot view contest page yet). This contest is not an official AtCoder round, so it is not rated.

The contest is ICPC style practice contest, and you can take part in it as a team. But you cannot use more than one computers, browse the internet, or copy-paste your library. Since AtCoder does not support team participation, please make a new account and share it if you want to compete as a team.

The problems are prepared by maroonrk, sigma425, sugim48, and me. Some of the problems were used in Petrozavodsk camp last winter, so if you participated in it, please refrain from competing in this contest. Note that the problems are not used in AtCoder Petrozavodsk Contest (see https://mirror.codeforces.com/blog/entry/57395 ).

The contest starts at 10:00 (GMT+9:00) and lasts for 5 hours. The standings will be frozen 60 minutes before the end of the contest.

Hope you enjoy the contest!

Recently, I start to use dlang in competitive programming. There are 3 dlang compiler, "DMD", "LDC", "GDC".

In competitive programming, best choice is "LDC", but in many online judge, we can use only "DMD" or "GDC".

I hope to many online judge install "LDC", so I write this blog.

Compiler compare

• DMD : Official compiler. Can use latest language version. Moderate Fast.
• LDC : based on llvm. Moderate new. Very Fast.
• GDC : based on gcc. Not new, Moderate Fast.

How to install ldc

1. Go to github's release page https://github.com/ldc-developers/ldc/releases
2. Download ldc(If you use 64bit-linux, ldc2-1.2.0-linux-x86_64.tar.xz, in now)
3. Extract
4. ADD /your/download/path/ldc2-1.2.0-linux-x86_64/bin to $PATH.

How to use ldc

• Debug mode : ldc2 -d-debug A.d

• Release mode(and optimize) : ldc2 -O -release A.d