I would also recommend Jeff Erickson's (UIUC) book on algorithms freely available here ( http://www.cs.uiuc.edu/~jeffe/teaching/algorithms/ http://www.cs.uiuc.e

I would also recommend Jeff Erickson's (UIUC) book on algorithms freely available here ( http://www.cs.uiuc.edu/~jeffe/teaching/algorithms/ http://www.cs.uiuc.edu/~jeffe/teaching/algorithms/ ). It is very well written challenging material.