It is strongly advised to run your code on your own computer with the sample input we provide before submitting.
Remove all extra debugging code and/or input prompts from your code before submitting. The judge is very strict — it requires your output to match exactly.
You do not have to have all your output after all the input. You can output as you're reading input because the judge will redirect the output to a file, so there is no chance of input mixing with output as would happen if you typed the input on a console.
Most input files have a single trailing newline.
Don't try to make a GUI. None of the problems on the judge will need it.
For Java users, do not create more than one Scanner in your program.
Ensure your program works with the sample input, however, just because it works with the sample input doesn't guarantee that it will earn full points. Read the problem statement very carefully to look for things you may have missed on the first read-through. It is not forbidden — in fact, even encouraged to make your own test cases to debug your program on.
Programs are expected to be deterministic. If you are using a random number generator, ensure it has a fixed seed. Rejudging may happen without prior notice.