Good night / dawn / morning / day / sunset / evening / night Codeforces! The other day, it became interesting how you can speed up the writing of codes using the definition and all sorts of useful functions in C ++ to increase your performance during contests, who can advise what?

And it is also interesting on which program is best to write (for example Codeblocks, VS ...).

Thank you all in advance for the answers and all the good mood)