Hmm. One of the best exercises I ever had to solve took me almost a day. [1] I have actually rewritten it twice, once in the manner they said they would have wanted it (same repo) and once in Python. (I didn't get the job, they didn't like the style I was using.)

I don't mind long coding exercises, it's what I do all day anyway. Better than watching yet another episode of NCIS or what have you :)

[1] https://github.com/mdpopescu/public/tree/master/SocialNetwor...