"achieved 95% accuracy in # the # of anonymous code. That was based on data from 250 coders over multiple years, averaging 630 lines of code per author." "looked at C++ source code from the 2008 to 2014 competitions written by more than 100,000 contestants." (from: CSI Computer Science: Your coding style can give you away http://www.itworld.com/article/2876179/csi-computer-science-your-coding-style-can-give-you-away.html )