I gonna study at Stanford and Princeton

I read about this in karriere . Many of the top universities in the US offer free online material for their lectures. Haven't checked this out in detail but it sounds like it is really good material including exercises and even video material. Go here for the article on the karriere.de homepage.

Here's the link list for your convenience

Berkeley, University of California: itunes.berkeley.edu; webcast.berkeley.edu Carnegie Mellon University: www.cmu.edu/oli Johns Hopkins University Bloomberg School of Public Health: ocw.jhsph.edu Massachusetts Institute of Technology (MIT): ocw.mit.edu University of Notre Dame: ocw.nd.edu Princeton: www.princeton.edu/WebMedia/lectures Stanford University: itunes.stanford.edu Tufts University: www.ocw.tufts.edu Utah State University: ocw.usu.edu