In my time in college I helped a lot of fellow students work through a lot of assignments. I sat down with them and helped them to think through the problem and find examples to learn from that weren't full solutions to the assignment. I helped them find difficult bugs in their implementation by pointing them in the right direction or showing them debugging tricks I found helpful.

What I didn't do was show them my implementation or even talk about how I solved it. Yeah, doing it the long way takes a bit more effort, but the result is that the students I helped actually understood the code they submitted and were better equipped to solve the next assignment without help.