Programming contest assignments, first level:
1. "...if you don't know how to return values from a function, you can just print them"
2. "...if you don't know how to read files, you can assume data is in global variables"
3. Required recursion
4. "...and estimate its time complexity.", "You may pre-process the data, but use at most o(n^3)", "your algorithm must use under n^3 operations"

That escalated quickly!