CCSC-E Programming Contest problems
In 2014–2022 (except for 2019) I helped run the CCSC Eastern conference programming contest. This page links to the problems we used.
The problems were written by T. J. Highley, Todd Neller, David Babcock, Steve Kennedy, Dan Joyce, me, and I think others as well.
I can't say with certainty what the copyright/license situation is for these problems, but I feel confident that it is fine to use them as practice problems.