CodeChef solutions and tidbits...
A collection of my solutions to competitive programming questions.
Sure, just follow the GPL license (and keep in mind that plagiarising source codes for contests would essentially disqualify you).
The file name is the code for the question on the site. That's all.
Practice, improving your solutions, not a lot.
A standard CP method to enable fast I/O. See https://stackoverflow.com/questions/31162367/significance-of-ios-basesync-with-stdiofalse-cin-tienull for exact clarification. It IS C++-specific.
Because it is the best option for CP. C++ comes with STL (Standard Template Library) while most do not. Remember that other languages might offer better options depending on the solution required. Other popular languages for CP are Java, C and Python, do check them out.
CodeChef, Codeforces, Topcoder, Project Euler... the list goes on.