If you are using C++ to create an OI problem, Testlib is an excellent helper tool when writing related programs (generator, validator, checker, interactor). It has become indispensable for OI problem authors from Russia and some other countries, and many competitions are using it as well: ROI, ICPC regional competitions, all Codeforces rounds...

The Testlib library has only one file called testlib.h, so you only need to add #include "testlib.h" at the beginning of the program.

The specific usage of Testlib:

Testlib is fully compatible with Polygon which is developed by Codeforces.

testlib.h was migrated from testlib.pas in 2005 and has been updated ever since. Testlib is compatible with most compilers, such as VC++, GCC g++, and is compatible with C++11.

This article is mainly translated from Testlib - Codeforces. The GitHub repository of testlib.h is MikeMirzayanov/testlib.