These are a few examples of complete problems.
This is a basic problem that asks for a program that computes the difference between integers. It should be a good starting point if you want to learn how the problem format works.
This is a simple example of an interactive problem where there is no fixed input to process, but the solution instead communicates back and forth with a validator program.
This is a problem that just asks for a program that prints Hello World!. It is a somewhat atypical problem since it does not have any
input. This problem also illustrates having problem statements in
more than one language.
This is an example of a scoring problem where submissions can get different scores depending on which test groups they solve. It also demonstrates how an input validator might check different constraints for different test groups.