Every year I think I'm going to do these daily, and every year I have a Github graveyard ^^;
Also, anyone participating should also check out the subreddit for it! It's pretty active year-round and the guy who does all of it (seriously, all of it. I'm not convinced this guy sleeps at all during the year, let alone in December) is very active and maintains solution threads every day.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.