I subscribed to the Daily Coding Problem mailing list a while ago. These folks will email you a coding problem to solve using whatever language you prefer (though some problems tend to suggest a language by virtue of the test cases provided). For a premium, they’ll also send you the solutions.
As of April 10th, I’ve received around 1683 coding problems to solve. I haven’t implemented many solutions because I’ve been slacking off, but I stash what I have implemented in a GitHub repo to show off:
https://github.com/hiimalexjgarcia/dailycodingproblem
I really need to jump back into this. 🙂