[kd1220]

They're what you make of it. Those problems are generally far removed from what you would actually do at most tech companies. Regardless, if they're complicated enough and you come up with a working solution, it does hone your problem solving skills. Don't do it to be top on a leader board or to get an interview.

Contributing to an open source project is also valuable, but in a different way. Open source projects require you to navigate through bug lists, socialize with other coders, read specs, analyze and repair a (mostly) functioning system. Overall, it will help you gain perspective on creating software.