When applying for a phd, does a hiring committee cares about winning in various programming/data-mining contests? When applying to a computer science PhD position in US, does it make sense to mention various significant achievements (finishing in top 5% percent) in programming/data-mining contests (topcoder, kaggle, hackerrank). 

These competitions have their weight for tech giants, but does a PhD hiring committee takes them into consideration? If so, it would be nice to know how much weight do they have and what is the best way to present them?
Yes, they matter to PhD hiring committees, because they show potential.

I believe you should include such achievements in a "Distinctions" or "Awards" section in your CV.