For some additional reading on algorithms and algorithmic complexity I recomend the following books:

The Design and Analysis of Computer Algorithms by A.V. Aho, J.E. Hopcroft, and J.D. Ullman(thorough explainations of important big-O, big-Omega, and big-Theta results

Handbook of Theoretical Computer Science, Volume A: Algorithms and Complexity by Jan Van Leeuwen(good chapters on abelian groups and vector analysis algorithms)

The Art of Computer Programming by Donald Knuth (this has 3 volumes and all are well worth the hefty price tag, great coverage of sorting algorithms)

Introduction to Algorithms by Thomas H. Cormen(despite the title this book is NOT written on an elementary level and is mathematically intensive, but if you are possess the necessary talent to excel in this field that won't be a problem anyway)