What reason would your professor have to have you take it down, at least past your due date? One could claim copyright on the project itself if you shared the files, or if you kept the original framework a course might provide, but the work you did is yours.

It's not like heap allocators are hard to come by, there's one right there in the Linux source code.

I've had plenty of courses where professors were afraid of answer sheets leaking out because they intended to use the exact same tests and practicals the year after. Those were always the courses where someone had a copy of last year's answers that was passed around between groups of students. You can't rely on secrecy to save yourself from having to come up with different tests if you hand out a piece of paper to 50 or even 300 people.